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准二维钙钛矿太阳能电池的研究进展

魏静 王秋雯 孙相彧 李红博

魏静, 王秋雯, 孙相彧, 李红博. 准二维钙钛矿太阳能电池的研究进展[J]. 中国光学. doi: 10.37188/CO.2020-0082
引用本文: 魏静, 王秋雯, 孙相彧, 李红博. 准二维钙钛矿太阳能电池的研究进展[J]. 中国光学. doi: 10.37188/CO.2020-0082
WEI Jing, WANG Qiu-wen, SUN Xiang-yu, LI Hong-bo. Research progress of quasi-two-dimensional perovskite solar cells[J]. Chinese Optics. doi: 10.37188/CO.2020-0082
Citation: WEI Jing, WANG Qiu-wen, SUN Xiang-yu, LI Hong-bo. Research progress of quasi-two-dimensional perovskite solar cells[J]. Chinese Optics. doi: 10.37188/CO.2020-0082

准二维钙钛矿太阳能电池的研究进展

doi: 10.37188/CO.2020-0082
基金项目: 国家自然科学基金(21701015,21811530054)
详细信息
    作者简介:

    魏 静(1990—),女,河北保定人,博士,特别副研究员,2017年于北京大学获得博士学位,现为北京理工大学材料学院特别副研究员,主要从事新型光伏材料与器件方面的研究。E-mail:weijing@bit.edu.cn

    李红博(1982—),男,河南郑州人,博士,教授,博士生导师,2010年于中国科学院理化技术研究所获得物理化学博士学位,现为北京理工大学教授,主要从事无机半导体纳米晶的可控合成,光谱性质研究以及光电器件的应用开发研究。E-mail:hongbo.li@bit.edu.cn

  • 中图分类号: TM914.4

Research progress of quasi-two-dimensional perovskite solar cells

Funds: The National Natural Science Foundation of China (No. 21701015 and 21811530054)
More Information
    Corresponding author: hongbo.li@bit.edu.cn
  • 摘要: 目前,钙钛矿太阳能电池的光电转换效率已超过25%,飞速提升的效率使得人们越来越期待商业化的应用,但钙钛矿材料的稳定性问题却是其商业化所面临的最大挑战,准二维钙钛矿的设计有望解决这一问题。利用大的有机间隔阳离子的疏水性和热稳定性,以及提高的晶体形成能和更加稳固的结构,准二维钙钛矿能够有效提高钙钛矿的稳定性;此外,准二维钙钛矿对钙钛矿薄膜的形态也具有明显的改善作用,可代替反溶剂工程,简化工艺,满足钙钛矿的工业化生产要求。然而,由于绝缘的有机间隔阳离子导致的相对大的带隙和低的载流子迁移率,阻碍了载流子传输,准二维钙钛矿太阳能电池的效率仍然与三维钙钛矿相差较大。因此,对于准二维钙钛矿,必须对其特性和器件应用等进行进一步研究,实现器件性能的进一步优化。本文总结了准二维钙钛矿太阳能电池的研究进展,归纳了准二维钙钛矿的分子结构、准二维结构提升三维钙钛矿稳定性的方法和原理、准二维钙钛矿的相分布及其载流子传输特性,分析了准二维钙钛矿太阳能电池目前面临的问题并对其前景进行了展望,期望为制备高效稳定的准二维钙钛矿太阳能电池提供参考。
  • 图  1  (a)常见的二维/准二维钙钛矿的有机胺阳离子;(b)不同n值BA2MAn-1PbnI3n+1及PEA2MAn-1PbnI3n+1的带隙排列[35, 36];(c)二维钙钛矿、准二维钙钛矿与三维钙钛矿的结构(RNH3+为有机胺阳离子)[36]

    Figure  1.  (a) Common organic amine cations of two-dimensional / quasi-two-dimensional perovskite; (b) bandgap arrangement of BA2MAn-1PbnI3n+1 and PEA2MAn-1PbnI3n+1 with different n values; (c) structure of two-dimensional perovskite, quasi-two-dimensional perovskite and three-dimensional perovskite.

    图  2  (a-d) 准二维钙钛矿BA2MAn-1PbnI3n + 1片状和块状单晶的照片:(a, b) n=3,(c, d) n=4;(e) 单晶回溶技术制备BA2MAn-1PbnI3n + 1薄膜反应示意图[48]

    Figure  2.  (a-d) Pictures of the plate- and block-shaped single crystals of BA2MA2Pb3I10 (a and b) and BA2MA3Pb4I13 (c and d); (e) The formation processes of BA2MAn-1PbnI3n + 1 (n = 3 and 4) thin films based on their single-crystalline structures.

    图  3  (a) 暴露于相对湿度80 ± 5%和20 ± 2 °C条件下,FAPbI3,2D钙钛矿修饰的FAPbI3和2D钙钛矿修饰的FA0.98Cs0.02PbI3钙钛矿薄膜随时间演变的照片[63];(b) 在相对湿度80 ±5%和20 ±2 °C条件下,600 nm处薄膜吸收光谱的演变(误差线表示每种条件下从三张膜中测得的吸光度的标准偏差)[63];(c) 器件中的多晶3D钙钛矿薄膜和2D钙钛矿薄膜的晶界(通过紫外光电子能谱(UPS)和Tauc图分析)[63];(d) 掺入20%PEA的FASnI3钙钛矿薄膜的掠入射广角X射线散射(GIWAXS)图像[40];(e) 储存在氮气气氛手套箱中的基于FASnI3和20%PEA掺杂的钙钛矿薄膜的未封装器件的PCE衰减示意图[40]

    Figure  3.  (a) Photos of the perovskite films incorporating bare FAPbI3, FAPbI3 with 2D perovskite and FA0.98Cs0.02PbI3 with 2D perovskite exposed to relative humidity (RH) of 80 ± 5% at 20 ± 2 °C for different times; (b) Evolution of the absorption of the films at 600 nm under RH 80 ± 5% at 20 ± 2 °C. The error bar indicates the standard deviation of the absorbance measured from the three films for each condition; (c) Schematics of the device incorporating polycrystalline a 3D perovskite film with 2D perovskite at grain boundaries; (d) GIWAXS images for 20% PEA film with Miller indices (orthorhombic system) of prominent peaks; (e) normalized PCE of the unencapsulated device based on FASnI3 and 20% PEA-doped perovskite film stored in a N2 atmosphere glovebox for over 100 h.

    图  4  (a)表面应力释放示意图:在(FAPbI3)0.85(MAPbBr3)0.15钙钛矿薄膜上进行OAI/PEAI后处理,通过晶格重构,松弛残余应力,调节沿薄膜厚度方向的残余应力分布,减轻晶格畸变程度;(b)引入PEA/OA释放残余应力机理示意图:低维钙钛矿成分主要在钙钛矿薄膜表面生成,在空间角度上提供了额外的结构灵活性,有效防止晶格变形;(c) 未封装钙钛矿太阳能电池在湿度16%-50%的空气中储存1000小时以上的长期稳定性测试(Reference指(FAPbI3)0.85(MAPbBr3)0.15钙钛矿;O-10指使用10×10-3 M浓度的OAI溶液后处理的(FAPbI3)0.85(MAPbBr3)0.15钙钛矿)[100]

    Figure  4.  (a) Schematic diagram of surface stress release: A post treatment process via lattice reconstruction on (FAPbI3)0.85(MAPbBr3)0.15 perovskites films was applied to modulate the residual stress distribution across film thicknesses in any direction, reducing the degree of lattice distortion; (b) Schematic diagram of the mechanism releasing residual stress by introducing PEA / OA: The 2D perovskite components mainly dwell at the surface of the perovskite thin films, which provides extra structural flexibility in the spatial perspective against lattice distortion; (c) The long-term stability test of the perovskite solar cells stored in air with a humidity of 16−50% for over 1000 h without encapsulation.

    图  5  (a) 原始BA2MA3Pb4I13钙钛矿薄膜、添加DMSO后钙钛矿薄膜的生长方向和相分布、添加反溶剂步骤后薄膜的生长方向[108];(b) 具有不同基底的常规(基底为氧化锡)和反式器件结构(基底为PEDOT:PSS)的示意图(红色圆球为空穴,蓝色圆球为电子)[108];(c, d) 介孔结构辅助控制BA2MAn-1PbnI3n + 1薄膜晶体取向示意图[48]

    Figure  5.  (a) Film growth direction and phase distribution of pristine BA2MA3Pb4I13 film, the film after adding DMSO and the film after adding antisolvent; (b) Schematics of conventional and inverted device architectures with different substrates (The red ball is the hole, and the blue ball is the electron); (c, d) The device architectures of BA2MAn-1PbnI3n + 1 (n = 3 and 4) solar cells based on single-crystalline precursors created with a modified hot-casting method.

    图  6  (a) 2D BA2MA2Sn3I10材料的不同薄膜生长取向(当使用二甲亚砜溶剂时钙钛矿薄膜取向平行于基板,当使用N,N-二甲基甲酰胺溶剂时翻转为垂直方向)[91];(b) ThMA作为间隔阳离子的2D / 3D钙钛矿结构示意图(有机层插入3D钙钛矿中并垂直于基板定向生长)[34]

    Figure  6.  (a) Different film growth orientations of 2D BA2MA2Sn3I10 materials (2D perovskites thin film orientation is parallel to the substrate when dimethyl sulfoxide solvent is used for deposition. This orientation can be flipped to perpendicular when N,N-dimethylformamide solvent is used.); (b) Schematic diagram of the 2D / 3D perovskite structure with ThMA as spacer cations (organic layer inserted into 3D perovskite and oriented perpendicularly to the substrate).

    表  1  基于不同有机胺阳离子的准二维钙钛矿光伏器件的性能参数及其T80寿命

    2D组分器件结构PCE (%)稳定性(T80测试条件
    FEA[54]FTO/c-TiO2/m-TiO2/FEA2PbI4-FAPbI3/spiro-OMeTAD /Au22.2>1000 h1Sun, RH 40%,MPPT
    PEA[55]FTO/c-TiO2/m-TiO2/ Cs0.1FA0.74MA0.13PbI2.48Br0.39-PEA2Pb2I4/spiro-OMeTAD/Au20.08>800 h1Sun, 50°C,氩气,MPPT
    AVA[56]FTO/c-TiO2/m-TiO2/ HOOC(CH2)4NH3PbI4-MAPbI3/spiro-OMeTAD/Au14.6>200 h1Sun, 55°C, 氩气,MPPT
    GA[57]FTO/c-TiO2/GAMA3Pb3I10/spiro-OMeTAD/Au18.4860 h空气,MPPT
    VBA[58]ITO/TiO2/VAB-(MAPbBr3)0.15(FAPbI3)0.85/spiro-OMeTAD/Au20.216 h空气,MPPT
    BA[59]FTO/SnO2/PCBM/(BA)x(FA0.83Cs0.17)1-xPbn(I0.6Br0.4)3/spiro-OMeTAD/Au19.5T80=4000 h T80=1000 h1Sun, 封装;1Sun, 未封装,空气
    EDBE[60]FTO/SnO2/(EDBE)PbI4-(FA0.83Cs0.17)Pb(I0.8Br0.2)3/spiro-OMeTAD/Au21.06>3000 h空气
    3BBA[61]ITO/PTAA/3BBAI-MACl-PbI2/PCBM/Cr/Au18.2>2400 hRH 40%
    ThMA[34]ITO /SnO2/ThMA-FA PbI3-MAPbI3/spiro-OMeTAD/MoO3-Ag21.49>1800 h;>600 h空气, RH30-50%;N2, 1Sun
    5-AVA[62]FTO/bl-TiO2/mp-TiO2/(FAPbI3)0.88(CsPbBr3)0.12/(5-AVA)2PbI4/CuSCN/ Au16.75>1440 hRH 10%
    PEA[63]ITO / SnO2/FAPbI3-PEA2Pb2I4/spiro-OMeTAD/Ag or Au20.641362 h0.9Sun, 40°C,RH 50%,
    PEA[64]FTO/c-TiO2/m-TiO2/(FAPbI3)0.85(MAPbBr3)0.15-PEA2Pb2I4/spiro-OMeTAD/Au14.3≈1200 hRH 70%
    ThMA[65]ITO/PEDOT:PSS/ThMA2Man-1PbnI3n+1/PCBM/BCP/Ag15.42>1000 hN2
    PDA[66]ITO/PEDOT:PSS/ PDAMAn−1PbnI3n+1 /C60/BCP/Ag13.0>1000 h >100 hRH 85%;RH 85%, 70°C
    MA3Bi2I9[67]FTO/ c-TiO2/MA3Bi2I9-MAPbI3/spiro-OMeTAD/Au18.97>800 h空气
    PTA[68]FTO/c-TiO2/SnO2/PTAI-MAPbI3/spiro-OMeTAD/Ag20.6>500 hN2, 1Sun
    4FPEA[69]ITO/PTAA/(4FPEA)2MA4Pb5I16/PCBM/PEI/Ag17.3>500 hN2, 55°C
    F-PEA[70]FTO/c-TiO2/(F-PEA)2MA4Pb5I16/spiro-OMeTAD/Au13.64300 h70°C, 空气
    PEA[71]FTO/TiO2/(PEA)2Csn-1PbnI3n+1/PTAA/Au13.65>288 hN2 , 80°C,RH 25-30%
    PEA[41]FTO/NiO/MAPbI3-PEA2Pb2I4/(PCBM/PN4N)/Ag19.89≈240 hRH 20-30%
    BA[72]ITO / PTAA/MAPbI3-BA2Pb2I4/PCBM/C60/BCP/Cu19.56>100 h95°C
    CA2PbI4[73]ITO/PEDOT:PSS/ CA2PbI4-MAPbIxCl3-x/PCBM/Rhodamine 101/Au13.86>100 hRH63±5%
    OA[74]FTO/c-TiO2/ns-TiO2/OAI- (FAPbI3)0.95(MA PbBr3)0.05 /DM/Au22.03100 hRH 85%
    DA[74]FTO/c-TiO2/ns-TiO2/DAI- (FAPbI3)0.95(MA PbBr3)0.05 /DM/Au21.89100 hRH 85%
    (表格中,MPPT代表测试条件为最大功率点追踪测试(maximum power point tracking)。PEA为Phenethylammonium(苯乙基碘化胺);EDBE为2,2-(ethylenedioxy)bis(ethylammonium)(2,2-(乙二氧基)双(乙胺));BA为butylammonium(丁基胺);AVA为aminovaleric acid(氨基戊酸);5-AVA为5‐ammoniumvaleric acid(5-氨戊酸);OA为oleylammonium;DA为dodecylammonium(十二烷基胺);FEA为pentafluorophenylethylammonium(五氟苯基乙基胺);3BBA为3‐bromobenzylammonium(3-溴苄基胺);PTA为phenyltrimethylammonium(苯基三甲基胺);GA为guanidinium(胍盐);VBA为4-vinylbenzylammonium(4-乙烯基苄基胺);4FPEA为fluorine‐substituted phenylethlammonium(氟取代的苯基乙胺);ThMA为2‐thiophenemethy-lammonium(2-噻吩甲基甲胺);F-PEA为4-fluorophenethylammonium(4-氟苯乙胺);PDA为Propane-1,3-diammonium(丙烷-1,3-二胺);RH为相对湿度;T80为器件PCE衰减至初始PCE的80%所需时间。)
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  • [1] LEE M M, TEUSCHER J, MIYASAKA T, <italic>et al</italic>. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites[J]. <italic>Science</italic>, 2012, 338(6107): 643-647. doi:  10.1126/science.1228604
    [2] LI ZH, YANG M J, PARK J S, <italic>et al</italic>. Stabilizing perovskite structures by tuning tolerance factor: formation of formamidinium and cesium lead iodide solid-state alloys[J]. <italic>Chemistry of Materials</italic>, 2016, 28(1): 284-292. doi:  10.1021/acs.chemmater.5b04107
    [3] AMAT A, MOSCONI E, RONCA E, <italic>et al</italic>. Cation-induced band-gap tuning in organohalide perovskites: interplay of spin–orbit coupling and octahedra tilting[J]. <italic>Nano Letters</italic>, 2014, 14(6): 3608-3616. doi:  10.1021/nl5012992
    [4] KIM H S, IM S H, PARK N G. Organolead halide perovskite: new horizons in solar cell research[J]. <italic>The Journal of Physical Chemistry C</italic>, 2014, 118(11): 5615-5625. doi:  10.1021/jp409025w
    [5] GREEN M A, HO-BAILLIE A, SNAITH H J. The emergence of perovskite solar cells[J]. <italic>Nature Photonics</italic>, 2014, 8(7): 506-514. doi:  10.1038/nphoton.2014.134
    [6] CORREA-BAENA J P, SALIBA M, BUONASSISI T, <italic>et al</italic>. Promises and challenges of perovskite solar cells[J]. <italic>Science</italic>, 2017, 358(6364): 739-744. doi:  10.1126/science.aam6323
    [7] LI W, WANG ZH M, DESCHLER F, <italic>et al</italic>. Chemically diverse and multifunctional hybrid organic–inorganic perovskites[J]. <italic>Nature Reviews Materials</italic>, 2017, 2(3): 16099. doi:  10.1038/natrevmats.2016.99
    [8] CHEN SH, SHI G Q. Two-dimensional materials for halide perovskite-based optoelectronic devices[J]. <italic>Advanced Materials</italic>, 2017, 29(24): 1605448. doi:  10.1002/adma.201605448
    [9] XING G CH, MATHEWS N, SUN SH Y, <italic>et al</italic>. Long-range balanced electron- and hole-transport lengths in organic-inorganic CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>[J]. <italic>Science</italic>, 2013, 342(6156): 344-347. doi:  10.1126/science.1243167
    [10] PROTESESCU L, YAKUNIN S, BODNARCHUK M I, <italic>et al</italic>. Nanocrystals of cesium lead halide perovskites (CsPbX<sub>3</sub>, X = Cl, Br, and I): Novel optoelectronic materials showing bright emission with wide color gamut[J]. <italic>Nano Letters</italic>, 2015, 15(6): 3692-3696. doi:  10.1021/nl5048779
    [11] WEI J, SHI C L, ZHAO Y CH, <italic>et al</italic>. Potentials and challenges towards application of perovskite solar cells[J]. <italic>Science China Materials</italic>, 2016, 59(9): 769-778. doi:  10.1007/s40843-016-5082-4
    [12] WEI J, ZHAO Q, LI H, <italic>et al</italic>. Perovskite solar cells: promise of photovoltaics[J]. <italic>SCIENTIA SINICA Technologica</italic>, 2014, 44(8): 801-821. doi:  10.1360/N092014-00135
    [13] KOJIMA A, TESHIMA K, SHIRAI Y, <italic>et al</italic>. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells[J]. <italic>Journal of the American Chemical Society</italic>, 2009, 131(17): 6050-6051. doi:  10.1021/ja809598r
    [14] NREL efficiency chart[EB/OL]. [2020-03-11]. https://www.nrel.gov/pv/cell-efficiency.html.
    [15] WANG Z, SHI Z J, LI T T, <italic>et al</italic>. Stability of perovskite solar cells: a prospective on the substitution of the A cation and X anion[J]. <italic>Angewandte Chemie International Edition</italic>, 2017, 56(5): 1190-1212. doi:  10.1002/anie.201603694
    [16] LI ZH, XIAO CH X, YANG Y, <italic>et al</italic>. Extrinsic ion migration in perovskite solar cells[J]. <italic>Energy </italic>&<italic>Environmental Science</italic>, 2017, 10(5): 1234-1242.
    [17] CHEN B, RUDD P N, YANG SH, <italic>et al</italic>. Imperfections and their passivation in halide perovskite solar cells[J]. <italic>Chemical Society Reviews</italic>, 2019, 48(14): 3842-3867. doi:  10.1039/C8CS00853A
    [18] LANG F, SHARGAIEVA O, BRUS V V, <italic>et al</italic>. Influence of radiation on the properties and the stability of hybrid perovskites[J]. <italic>Advanced Materials</italic>, 2018, 30(3): 1702905. doi:  10.1002/adma.201702905
    [19] WEI J, LI H, ZHAO Y CH, <italic>et al</italic>. Suppressed hysteresis and improved stability in perovskite solar cells with conductive organic network[J]. <italic>Nano Energy</italic>, 2016, 26: 139-147. doi:  10.1016/j.nanoen.2016.05.023
    [20] WEI J, ZHAO Y CH, LI H, <italic>et al</italic>. Hysteresis analysis based on the ferroelectric effect in hybrid perovskite solar cells[J]. <italic>The Journal of Physical Chemistry Letters</italic>, 2014, 5(21): 3937-3945. doi:  10.1021/jz502111u
    [21] ZHAO Y CH, WEI J, LI H, <italic>et al</italic>. A polymer scaffold for self-healing perovskite solar cells[J]. <italic>Nature Communications</italic>, 2016, 7(1): 10228. doi:  10.1038/ncomms10228
    [22] WEI J, GUO F W, WANG X, <italic>et al</italic>. SnO<sub>2</sub>-in-polymer matrix for high-efficiency perovskite solar cells with improved reproducibility and stability[J]. <italic>Advanced Materials</italic>, 2018, 30(52): 1805153. doi:  10.1002/adma.201805153
    [23] WEI J, GUO F W, LIU B, <italic>et al</italic>. UV-inert ZnTiO<sub>3</sub> electron selective layer for photostable perovskite solar cells[J]. <italic>Advanced Energy Materials</italic>, 2019, 9(40): 1901620. doi:  10.1002/aenm.201901620
    [24] LEI Y, GU L Y, HE W W, <italic>et al</italic>. Intrinsic charge carrier dynamics and device stability of perovskite/ZnO mesostructured solar cells in moisture[J]. <italic>Journal of Materials Chemistry A</italic>, 2016, 4(15): 5474-5481. doi:  10.1039/C6TA00614K
    [25] ETGAR L. The merit of perovskite's dimensionality; can this replace the 3D halide perovskite?[J]. <italic>Energy </italic>&<italic>Environmental Science</italic>, 2018, 11(2): 234-242.
    [26] TSAI H, NIE W Y, BLANCON J C, <italic>et al</italic>. High-efficiency two-dimensional Ruddlesden-Popper perovskite solar cells[J]. <italic>Nature</italic>, 2016, 536(7616): 312-316. doi:  10.1038/nature18306
    [27] ZHANG Y L, WANG P J, TANG M CH, <italic>et al</italic>. Dynamical transformation of two-dimensional perovskites with alternating cations in the interlayer space for high-performance photovoltaics[J]. <italic>Journal of the American Chemical Society</italic>, 2019, 141(6): 2684-2694. doi:  10.1021/jacs.8b13104
    [28] ZHANG ZH SH, FANG W H, LONG R, <italic>et al</italic>. Exciton dissociation and suppressed charge recombination at 2D perovskite edges: Key roles of unsaturated halide bonds and thermal disorder[J]. <italic>Journal of the American Chemical Society</italic>, 2019, 141(39): 15557-15566. doi:  10.1021/jacs.9b06046
    [29] ZHOU N, HUANG B L, SUN M Z, <italic>et al</italic>. The spacer cations interplay for efficient and stable layered 2D perovskite solar cells[J]. <italic>Advanced Energy Materials</italic>, 2020, 10(1): 1901566. doi:  10.1002/aenm.201901566
    [30] LI C H, LIAO M Y, CHEN C H, <italic>et al</italic>. Recent progress of anion-based 2D perovskites with different halide substitutions[J]. <italic>Journal of Materials Chemistry C</italic>, 2020, 8(13): 4294-4302. doi:  10.1039/C9TC06964J
    [31] LI X T, KE W J, TRAORÉ B, <italic>et al</italic>. Two-dimensional Dion-Jacobson hybrid lead iodide perovskites with aromatic diammonium cations[J]. <italic>Journal of the American Chemical Society</italic>, 2019, 141(32): 12880-12890. doi:  10.1021/jacs.9b06398
    [32] MAO L L, STOUMPOS C C, KANATZIDIS M G. Two-dimensional hybrid halide perovskites: principles and promises[J]. <italic>Journal of the American Chemical Society</italic>, 2019, 141(3): 1171-1190. doi:  10.1021/jacs.8b10851
    [33] GANGADHARAN D T, MA D L. Searching for stability at lower dimensions: current trends and future prospects of layered perovskite solar cells[J]. <italic>Energy </italic>&<italic>Environmental Science</italic>, 2019, 12(10): 2860-2889.
    [34] ZHOU T, LAI H T, LIU T T, <italic>et al</italic>. Highly efficient and stable solar cells based on crystalline oriented 2D/3D hybrid perovskite[J]. <italic>Advanced Materials</italic>, 2019, 31(32): 1901242.
    [35] FU Y P, ZHENG W H, WANG X X, <italic>et al</italic>. Multicolor heterostructures of two-dimensional layered halide perovskites that show interlayer energy transfer[J]. <italic>Journal of the American Chemical Society</italic>, 2018, 140(46): 15675-15683. doi:  10.1021/jacs.8b07843
    [36] GRANCINI G, NAZEERUDDIN M K. Dimensional tailoring of hybrid perovskites for photovoltaics[J]. <italic>Nature Reviews Materials</italic>, 2019, 4(1): 4-22. doi:  10.1038/s41578-018-0065-0
    [37] TIAN X X, ZHANG Y ZH, ZHENG R K, <italic>et al</italic>. Two-dimensional organic–inorganic hybrid Ruddlesden–Popper perovskite materials: Preparation, enhanced stability, and applications in photodetection[J]. <italic>Sustainable Energy </italic>&<italic>Fuels</italic>, 2020, 4(5): 2087-2113.
    [38] HUANG P, KAZIM S, WANG M K, <italic>et al</italic>. Toward phase stability: dion–Jacobson layered perovskite for solar cells[J]. <italic>ACS Energy Letters</italic>, 2019, 4(12): 2960-2974. doi:  10.1021/acsenergylett.9b02063
    [39] MA S, CAI M L, CHENG T, <italic>et al</italic>. Two-dimensional organic-inorganic hybrid perovskite: from material properties to device applications[J]. <italic>Science China Materials</italic>, 2018, 61(10): 1257-1277. doi:  10.1007/s40843-018-9294-5
    [40] LIAO Y Q, LIU H F, ZHOU W J, <italic>et al</italic>. Highly oriented low-dimensional tin halide perovskites with enhanced stability and photovoltaic performance[J]. <italic>Journal of the American Chemical Society</italic>, 2017, 139(19): 6693-6699. doi:  10.1021/jacs.7b01815
    [41] BAI Y, XIAO SH, HU CH, <italic>et al</italic>. Dimensional engineering of a graded 3D–2D halide perovskite interface enables ultrahigh <italic>V</italic><sub>oc</sub> enhanced stability in the p-i-n photovoltaics[J]. <italic>Advanced Energy Materials</italic>, 2017, 7(20): 1701038. doi:  10.1002/aenm.201701038
    [42] GAN X Y, WANG O, LIU K Y, <italic>et al</italic>. 2D homologous organic-inorganic hybrids as light-absorbers for planer and nanorod-based perovskite solar cells[J]. <italic>Solar Energy Materials and Solar Cells</italic>, 2017, 162: 93-102. doi:  10.1016/j.solmat.2016.12.047
    [43] LI N, ZHU Z L, CHUEH CH CH, <italic>et al</italic>. Mixed cation FA<sub><italic>x</italic></sub>PEA<sub>1–<italic>x</italic></sub>PbI<sub>3</sub> with enhanced phase and ambient stability toward high-performance perovskite solar cells[J]. <italic>Advanced Energy Materials</italic>, 2017, 7(1): 1601307. doi:  10.1002/aenm.201601307
    [44] HA S T, LIU X F, ZHANG Q, <italic>et al</italic>. Synthesis of organic–inorganic lead halide perovskite nanoplatelets: towards high-performance perovskite solar cells and optoelectronic devices[J]. <italic>Advanced Optical Materials</italic>, 2014, 2(9): 838-844. doi:  10.1002/adom.201400106
    [45] WANG Y P, SHI Y F, XIN G Q, <italic>et al</italic>. Two-dimensional van der Waals epitaxy kinetics in a three-dimensional perovskite halide[J]. <italic>Crystal Growth </italic>&<italic>Design</italic>, 2015, 15(10): 4741-4749.
    [46] QUAN L N, YUAN M J, COMIN R, <italic>et al</italic>. Ligand-stabilized reduced-dimensionality perovskites[J]. <italic>Journal of the American Chemical Society</italic>, 2016, 138(8): 2649-2655. doi:  10.1021/jacs.5b11740
    [47] LENG K, FU W, LIU Y P, <italic>et al</italic>. From bulk to molecularly thin hybrid perovskites[J]. <italic>Nature Reviews Materials</italic>, 2020, 5(7): 482-500. doi:  10.1038/s41578-020-0185-1
    [48] DANG Y Y, WEI J, LIU X L, <italic>et al</italic>. Layered hybrid perovskite solar cells based on single-crystalline precursor solutions with superior reproducibility[J]. <italic>Sustainable Energy </italic>&<italic>Fuels</italic>, 2018, 2(10): 2237-2243.
    [49] TAKEOKA Y, FUKASAWA M, MATSUI T, <italic>et al</italic>. Intercalated formation of two-dimensional and multi-layered perovskites in organic thin films[J]. <italic>Chemical Communications</italic>, 2005(3): 378-380. doi:  10.1039/b413398f
    [50] KAMMINGA M E, FANG H H, FILIP M R, <italic>et al</italic>. Confinement effects in low-dimensional lead iodide perovskite hybrids[J]. <italic>Chemistry of Materials</italic>, 2016, 28(13): 4554-4562. doi:  10.1021/acs.chemmater.6b00809
    [51] SUN SH Y, SALIM T, MATHEWS N, <italic>et al</italic>. The origin of high efficiency in low-temperature solution-processable bilayer organometal halide hybrid solar cells[J]. <italic>Energy </italic>&<italic>Environmental Science</italic>, 2014, 7(1): 399-407.
    [52] REN H, YU SH D, CHAO L F, <italic>et al</italic>. Efficient and stable Ruddlesden–Popper perovskite solar cell with tailored interlayer molecular interaction[J]. <italic>Nature Photonics</italic>, 2020, 14(3): 154-163. doi:  10.1038/s41566-019-0572-6
    [53] SONG J X, BIAN J, ZHENG E Q, <italic>et al</italic>. Efficient and environmentally stable perovskite solar cells based on ZnO electron collection layer[J]. <italic>Chemistry Letters</italic>, 2015, 44(5): 610-612. doi:  10.1246/cl.150056
    [54] LIU Y H, AKIN S, PAN L F, <italic>et al</italic>. Ultrahydrophobic 3D/2D fluoroarene bilayer-based water-resistant perovskite solar cells with efficiencies exceeding 22%[J]. <italic>Science Advances</italic>, 2019, 5(6): eaaw2543. doi:  10.1126/sciadv.aaw2543
    [55] CHO K T, GRANCINI G, LEE Y H, <italic>et al</italic>. Selective growth of layered perovskites for stable and efficient photovoltaics[J]. <italic>Energy </italic>&<italic>Environmental Science</italic>, 2018, 11(4): 952-959.
    [56] GRANCINI G, ROLDÁN-CARMONA C, ZIMMERMANN I, <italic>et al</italic>. One-year stable perovskite solar cells by 2D/3D interface engineering[J]. <italic>Nature Communications</italic>, 2017, 8(1): 15684. doi:  10.1038/ncomms15684
    [57] LUO T, ZHANG Y L, XU ZH, <italic>et al</italic>. Compositional control in 2D perovskites with alternating cations in the interlayer space for photovoltaics with efficiency over 18%[J]. <italic>Advanced Materials</italic>, 2019, 31(44): 1903848. doi:  10.1002/adma.201903848
    [58] PROPPE A H, WEI M Y, CHEN B, <italic>et al</italic>. Photochemically cross-linked quantum well ligands for 2D/3D perovskite photovoltaics with improved photovoltage and stability[J]. <italic>Journal of the American Chemical Society</italic>, 2019, 141(36): 14180-14189. doi:  10.1021/jacs.9b05083
    [59] WANG ZH P, LIN Q Q, CHMIEL F P, <italic>et al</italic>. Efficient ambient-air-stable solar cells with 2D–3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites[J]. <italic>Nature Energy</italic>, 2017, 2(9): 17135. doi:  10.1038/nenergy.2017.135
    [60] LI P W, ZHANG Y Q, LIANG CH, <italic>et al</italic>. Phase pure 2D perovskite for high-performance 2D–3D heterostructured perovskite solar cells[J]. <italic>Advanced Materials</italic>, 2018, 30(52): 1805323. doi:  10.1002/adma.201805323
    [61] YANG R, LI R ZH, CAO Y, <italic>et al</italic>. Oriented quasi-2D perovskites for high performance optoelectronic devices[J]. <italic>Advanced Materials</italic>, 2018, 30(51): 1804771. doi:  10.1002/adma.201804771
    [62] CHEN J ZH, SEO J Y, PARK N G. Simultaneous improvement of photovoltaic performance and stability by in situ formation of 2D perovskite at (FAPbI<sub>3</sub>)<sub>0.88</sub>(CsPbBr<sub>3</sub>)<sub>0.12</sub>/CuSCN interface[J]. <italic>Advanced Energy Materials</italic>, 2018, 8(12): 1702714. doi:  10.1002/aenm.201702714
    [63] LEE J W, DAI ZH H, HAN T H, <italic>et al</italic>. 2D perovskite stabilized phase-pure formamidinium perovskite solar cells[J]. <italic>Nature Communications</italic>, 2018, 9(1): 3021. doi:  10.1038/s41467-018-05454-4
    [64] LEE D S, YUN J S, KIM J, <italic>et al</italic>. Passivation of grain boundaries by phenethylammonium in formamidinium-methylammonium lead halide perovskite solar cells[J]. <italic>ACS Energy Letters</italic>, 2018, 3(3): 647-654. doi:  10.1021/acsenergylett.8b00121
    [65] LAI H T, KAN B, LIU T T, <italic>et al</italic>. Two-dimensional Ruddlesden–Popper perovskite with nanorod-like morphology for solar cells with efficiency exceeding 15%[J]. <italic>Journal of the American Chemical Society</italic>, 2018, 140(37): 11639-11646. doi:  10.1021/jacs.8b04604
    [66] MA CH Q, SHEN D, NG T W, <italic>et al</italic>. 2D perovskites with short interlayer distance for high-performance solar cell application[J]. <italic>Advanced Materials</italic>, 2018, 30(22): 1800710. doi:  10.1002/adma.201800710
    [67] HU Y Q, QIU T, BAI F, <italic>et al</italic>. Highly efficient and stable solar cells with 2D MA<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub>/3D MAPbI<sub>3</sub> heterostructured perovskites[J]. <italic>Advanced Energy Materials</italic>, 2018, 8(19): 1703620. doi:  10.1002/aenm.201703620
    [68] WANG X T, WANG Y, ZHANG T Y, <italic>et al</italic>. Steric mixed-cation 2D perovskite as a methylammonium locker to stabilize MAPbI<sub>3</sub>[J]. <italic>Angewandte Chemie International Edition</italic>, 2020, 59(4): 1469-1473. doi:  10.1002/anie.201911518
    [69] SHI J SH, GAO Y R, GAO X, <italic>et al</italic>. Fluorinated low-dimensional Ruddlesden–Popper perovskite solar cells with over 17% power conversion efficiency and improved stability[J]. <italic>Advanced Materials</italic>, 2019, 31(37): 1901673. doi:  10.1002/adma.201901673
    [70] ZHANG F, KIM D H, LU H P, <italic>et al</italic>. Enhanced charge transport in 2D perovskites via fluorination of organic cation[J]. <italic>Journal of the American Chemical Society</italic>, 2019, 141(14): 5972-5979. doi:  10.1021/jacs.9b00972
    [71] WANG K, LI ZH Z, ZHOU F G, <italic>et al</italic>. Ruddlesden–Popper 2D component to stabilize γ-CsPbI<sub>3</sub> perovskite phase for stable and efficient photovoltaics[J]. <italic>Advanced Energy Materials</italic>, 2019, 9(42): 1902529. doi:  10.1002/aenm.201902529
    [72] LIN Y, BAI Y, FANG Y J, <italic>et al</italic>. Enhanced thermal stability in perovskite solar cells by assembling 2D/3D stacking structures[J]. <italic>The Journal of Physical Chemistry Letters</italic>, 2018, 9(3): 654-658. doi:  10.1021/acs.jpclett.7b02679
    [73] MA CH Y, LENG CH Q, JI Y X, <italic>et al</italic>. 2D/3D perovskite hybrids as moisture-tolerant and efficient light absorbers for solar cells[J]. <italic>Nanoscale</italic>, 2016, 8(43): 18309-18314. doi:  10.1039/C6NR04741F
    [74] KIM H, LEE S U, LEE D Y, <italic>et al</italic>. Perovskite solar cells: optimal interfacial engineering with different length of alkylammonium halide for efficient and stable perovskite solar cells (Adv. Energy Mater. 47/2019)[J]. <italic>Advanced Energy Materials</italic>, 2019, 9(47): 1970187. doi:  10.1002/aenm.201970187
    [75] ZHENG Y F, YANG X Y, SU R, <italic>et al</italic>. High-performance CsPbI<sub><italic>x</italic></sub>Br<sub>3-<italic>x</italic></sub> all-inorganic perovskite solar cells with efficiency over 18% via spontaneous interfacial manipulation[J]. <italic>Advanced Functional Materials</italic>, 2020: 2000457. doi:  10.1002/adfm.202000457
    [76] KIM H S, SEO J Y, PARK N G. Material and device stability in perovskite solar cells[J]. <italic>ChemSusChem</italic>, 2016, 9(18): 2528-2540. doi:  10.1002/cssc.201600915
    [77] SUPASAI T, RUJISAMPHAN N, ULLRICH K, <italic>et al</italic>. Formation of a passivating CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>/PbI<sub>2</sub> interface during moderate heating of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> layers[J]. <italic>Applied Physics Letters</italic>, 2013, 103(18): 183906. doi:  10.1063/1.4826116
    [78] ARISTIDOU N, SANCHEZ-MOLINA I, CHOTCHUANGCHUTCHAVAL T, <italic>et al</italic>. The role of oxygen in the degradation of methylammonium lead trihalide perovskite photoactive layers[J]. <italic>Angewandte Chemie International Edition</italic>, 2015, 54(28): 8208-8212. doi:  10.1002/anie.201503153
    [79] LUO P F, XIA W, ZHOU SH W, <italic>et al</italic>. Solvent engineering for ambient-air-processed, phase-stable CsPbI<sub>3</sub> in perovskite solar cells[J]. <italic>The Journal of Physical Chemistry Letters</italic>, 2016, 7(18): 3603-3608. doi:  10.1021/acs.jpclett.6b01576
    [80] XUE J J, LEE J W, DAI ZH H, <italic>et al</italic>. Surface ligand management for stable FAPbI<sub>3</sub> perovskite quantum dot solar cells[J]. <italic>Joule</italic>, 2018, 2(9): 1866-1878. doi:  10.1016/j.joule.2018.07.018
    [81] FU Y P, REA M T, CHEN J, <italic>et al</italic>. Selective stabilization and photophysical properties of metastable perovskite polymorphs of CsPbI<sub>3</sub> in thin films[J]. <italic>Chemistry Of Materials</italic>, 2017, 29(19): 8385-8394. doi:  10.1021/acs.chemmater.7b02948
    [82] WANG Q, ZHENG X P, DENG Y H, <italic>et al</italic>. Stabilizing the <italic>α</italic>-phase of CsPbI<sub>3</sub> perovskite by sulfobetaine zwitterions in one-step spin-coating films[J]. <italic>Joule</italic>, 2017, 1(2): 371-382. doi:  10.1016/j.joule.2017.07.017
    [83] JIANG Y ZH, YUAN J, NI Y X, <italic>et al</italic>. Reduced-dimensional <italic>α</italic>-CsPbX<sub>3</sub> perovskites for efficient and stable photovoltaics[J]. <italic>Joule</italic>, 2018, 2(7): 1356-1368. doi:  10.1016/j.joule.2018.05.004
    [84] RONG Y G, HU Y, MEI A Y, <italic>et al</italic>. Challenges for commercializing perovskite solar cells[J]. <italic>Science</italic>, 2018, 361(6408): eaat8235. doi:  10.1126/science.aat8235
    [85] CHEN B, YU ZH SH, LIU K, <italic>et al</italic>. Grain engineering for perovskite/silicon monolithic tandem solar cells with efficiency of 25.4%[J]. <italic>Joule</italic>, 2019, 3(1): 177-190. doi:  10.1016/j.joule.2018.10.003
    [86] HOKE E T, SLOTCAVAGE D J, DOHNER E R, <italic>et al</italic>. Reversible photo-induced trap formation in mixed-halide hybrid perovskites for photovoltaics[J]. <italic>Chemical Science</italic>, 2015, 6(1): 613-617. doi:  10.1039/C4SC03141E
    [87] KIM D, JUNG H J, PARK I J, <italic>et al</italic>. Efficient, stable silicon tandem cells enabled by anion-engineered wide-bandgap perovskites[J]. <italic>Science</italic>, 2020, 368(6487): 155-160. doi:  10.1126/science.aba3433
    [88] KE W J, STOUMPOS C C, KANATZIDIS M G. “Unleaded” perovskites: status quo and future prospects of tin-based perovskite solar cells[J]. <italic>Advanced Materials</italic>, 2019, 31(47): 1803230. doi:  10.1002/adma.201803230
    [89] TSAI H, NIE W Y, BLANCON J C, <italic>et al</italic>. High-efficiency two-dimensional Ruddlesden–Popper perovskite solar cells[J]. <italic>Nature</italic>, 2016, 536(7616): 312-316. doi:  10.1038/nature18306
    [90] STOUMPOS C C, MAO L L, MALLIAKAS C D, <italic>et al</italic>. Structure–band gap relationships in hexagonal polytypes and low-dimensional structures of hybrid tin iodide perovskites[J]. <italic>Inorganic Chemistry</italic>, 2017, 56(1): 56-73. doi:  10.1021/acs.inorgchem.6b02764
    [91] CAO D H, STOUMPOS C C, YOKOYAMA T, <italic>et al</italic>. Thin films and solar cells based on semiconducting two-dimensional Ruddlesden–Popper (CH<sub>3</sub>(CH<sub>2</sub>)<sub>3</sub>NH<sub>3</sub>)<sub>2</sub>(CH<sub>3</sub>NH<sub>3</sub>)<sub><italic>n</italic>−1</sub>Sn<sub><italic>n</italic></sub>I<sub>3<italic>n</italic>+1</sub> perovskites[J]. <italic>ACS Energy Letters</italic>, 2017, 2(5): 982-990. doi:  10.1021/acsenergylett.7b00202
    [92] WANG F, JIANG X Y, CHEN H, <italic>et al</italic>. 2D-quasi-2D-3D hierarchy structure for tin perovskite solar cells with enhanced efficiency and stability[J]. <italic>Joule</italic>, 2018, 2(12): 2732-2743. doi:  10.1016/j.joule.2018.09.012
    [93] TSAI H, ASADPOUR R, BLANCON J C, <italic>et al</italic>. Light-induced lattice expansion leads to high-efficiency perovskite solar cells[J]. <italic>Science</italic>, 2018, 360(6384): 67-70. doi:  10.1126/science.aap8671
    [94] ZHAO J J, DENG Y H, WEI H T, <italic>et al</italic>. Strained hybrid perovskite thin films and their impact on the intrinsic stability of perovskite solar cells[J]. <italic>Science Advances</italic>, 2017, 3(11): eaao5616. doi:  10.1126/sciadv.aao5616
    [95] ROLSTON N, BUSH K A, PRINTZ A D, <italic>et al</italic>. Engineering stress in perovskite solar cells to improve stability[J]. <italic>Advanced Energy Materials</italic>, 2018, 8(29): 1802139. doi:  10.1002/aenm.201802139
    [96] LUO D Y, YANG W Q, WANG ZH P, <italic>et al</italic>. Enhanced photovoltage for inverted planar heterojunction perovskite solar cells[J]. <italic>Science</italic>, 2018, 360(6396): 1442-1446. doi:  10.1126/science.aap9282
    [97] GROTE C, BERGER R F. Strain tuning of tin–halide and lead–halide perovskites: a first-principles atomic and electronic structure study[J]. <italic>The Journal of Physical Chemistry C</italic>, 2015, 119(40): 22832-22837. doi:  10.1021/acs.jpcc.5b07446
    [98] ZHANG L, GENG W, TONG CH J, <italic>et al</italic>. Strain induced electronic structure variation in methyl-ammonium lead iodide perovskite[J]. <italic>Scientific Reports</italic>, 2018, 8(1): 7760. doi:  10.1038/s41598-018-25772-3
    [99] ALHARBI E A, ALYAMANI A Y, KUBICKI D J, <italic>et al</italic>. Atomic-level passivation mechanism of ammonium salts enabling highly efficient perovskite solar cells[J]. <italic>Nature Communications</italic>, 2019, 10(1): 3008. doi:  10.1038/s41467-019-10985-5
    [100] WANG H, ZHU CH, LIU L, <italic>et al</italic>. Interfacial residual stress relaxation in perovskite solar cells with improved stability[J]. <italic>Advanced Materials</italic>, 2019, 31(48): 1904408. doi:  10.1002/adma.201904408
    [101] NAMVAR A, DEHGHANY M, SOHRABPOUR S, <italic>et al</italic>. Thermal residual stresses in silicon thin film solar cells under operational cyclic thermal loading: A finite element analysis[J]. <italic>Solar Energy</italic>, 2016, 135: 366-373. doi:  10.1016/j.solener.2016.05.058
    [102] LEE S M, YEON D H, MOHANTY B C, <italic>et al</italic>. Tensile stress-dependent fracture behavior and its influences on photovoltaic characteristics in flexible PbS/CdS thin-film solar cells[J]. <italic>ACS Applied Materials </italic>&<italic>Interfaces</italic>, 2015, 7(8): 4573-4578.
    [103] AHN G H, AMANI M, RASOOL H, <italic>et al</italic>. Strain-engineered growth of two-dimensional materials[J]. <italic>Nature Communications</italic>, 2017, 8(1): 608. doi:  10.1038/s41467-017-00516-5
    [104] MURALI B, YENGEL E, PENG W, <italic>et al</italic>. Temperature-induced lattice relaxation of perovskite crystal enhances optoelectronic properties and solar cell performance[J]. <italic>The Journal of Physical Chemistry Letters</italic>, 2017, 8(1): 137-143. doi:  10.1021/acs.jpclett.6b02684
    [105] ZHU CH, NIU X X, FU Y H, <italic>et al</italic>. Strain engineering in perovskite solar cells and its impacts on carrier dynamics[J]. <italic>Nature Communications</italic>, 2019, 10(1): 815. doi:  10.1038/s41467-019-08507-4
    [106] ZHENG Y T, NIU T T, RAN X Q, <italic>et al</italic>. Unique characteristics of 2D Ruddlesden–Popper (2DRP) perovskite for future photovoltaic application[J]. <italic>Journal of Materials Chemistry A</italic>, 2019, 7(23): 13860-13872. doi:  10.1039/C9TA03217G
    [107] ZHANG J, QIN J J, WANG M SH, <italic>et al</italic>. Uniform permutation of quasi-2D perovskites by vacuum poling for efficient, high-fill-factor solar cells[J]. <italic>Joule</italic>, 2019, 3(12): 3061-3071. doi:  10.1016/j.joule.2019.09.020
    [108] ZHOU M, FEI CH B, SARMIENTO J S, <italic>et al</italic>. Manipulating the phase distributions and carrier transfers in hybrid quasi-two-dimensional perovskite films[J]. <italic>Solar RRL</italic>, 2019, 3(4): 1800359. doi:  10.1002/solr.201800359
    [109] LIU T F, JIANG Y Y, QIN M CH, <italic>et al</italic>. Tailoring vertical phase distribution of quasi-two-dimensional perovskite films via surface modification of hole-transporting layer[J]. <italic>Nature Communications</italic>, 2019, 10(1): 878. doi:  10.1038/s41467-019-08843-5
    [110] WEI J, WANG X, SUN X Y, <italic>et al</italic>. Polymer assisted deposition of high-quality CsPbI<sub>2</sub>Br film with enhanced film thickness and stability[J]. <italic>Nano Research</italic>, 2020, 13(3): 684-690. doi:  10.1007/s12274-020-2675-2
    [111] QING J, LIU X K, LI M J, <italic>et al</italic>. Aligned and graded type-II Ruddlesden–Popper perovskite films for efficient solar cells[J]. <italic>Advanced Energy Materials</italic>, 2018, 8(21): 1800185. doi:  10.1002/aenm.201800185
    [112] LI M H, YEH H H, CHIANG Y H, <italic>et al</italic>. Highly efficient 2D/3D hybrid perovskite solar cells via low-pressure vapor-assisted solution process[J]. <italic>Advanced Materials</italic>, 2018, 30(30): 1801401. doi:  10.1002/adma.201801401
    [113] WU G B, LI X, ZHOU J Y, <italic>et al</italic>. Fine multi-phase alignments in 2D perovskite solar cells with efficiency over 17% via slow post-annealing[J]. <italic>Advanced Materials</italic>, 2019, 31(42): 1903889. doi:  10.1002/adma.201903889
    [114] GAO L G, ZHANG F, XIAO CH X, <italic>et al</italic>. Improving charge transport via intermediate-controlled crystal growth in 2D perovskite solar cells[J]. <italic>Advanced Functional Materials</italic>, 2019, 29(47): 1901652. doi:  10.1002/adfm.201901652
    [115] KE W J, MAO L L, STOUMPOS C C, <italic>et al</italic>. Compositional and solvent engineering in Dion–Jacobson 2D perovskites boosts solar cell efficiency and stability[J]. <italic>Advanced Energy Materials</italic>, 2019, 9(10): 1803384. doi:  10.1002/aenm.201803384
    [116] CHEN A Z, SHIU M, MA J H, <italic>et al</italic>. Origin of vertical orientation in two-dimensional metal halide perovskites and its effect on photovoltaic performance[J]. <italic>Nature Communications</italic>, 2018, 9(1): 1336. doi:  10.1038/s41467-018-03757-0
    [117] ZHENG K B, CHEN Y N, SUN Y, <italic>et al</italic>. Inter-phase charge and energy transfer in Ruddlesden–Popper 2D perovskites: critical role of the spacing cations[J]. <italic>Journal of Materials Chemistry A</italic>, 2018, 6(15): 6244-6250. doi:  10.1039/C8TA01518J
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出版历程

准二维钙钛矿太阳能电池的研究进展

doi: 10.37188/CO.2020-0082
    基金项目:  国家自然科学基金(21701015,21811530054)
    作者简介:

    魏 静(1990—),女,河北保定人,博士,特别副研究员,2017年于北京大学获得博士学位,现为北京理工大学材料学院特别副研究员,主要从事新型光伏材料与器件方面的研究。E-mail:weijing@bit.edu.cn

    李红博(1982—),男,河南郑州人,博士,教授,博士生导师,2010年于中国科学院理化技术研究所获得物理化学博士学位,现为北京理工大学教授,主要从事无机半导体纳米晶的可控合成,光谱性质研究以及光电器件的应用开发研究。E-mail:hongbo.li@bit.edu.cn

  • 中图分类号: TM914.4

摘要: 目前,钙钛矿太阳能电池的光电转换效率已超过25%,飞速提升的效率使得人们越来越期待商业化的应用,但钙钛矿材料的稳定性问题却是其商业化所面临的最大挑战,准二维钙钛矿的设计有望解决这一问题。利用大的有机间隔阳离子的疏水性和热稳定性,以及提高的晶体形成能和更加稳固的结构,准二维钙钛矿能够有效提高钙钛矿的稳定性;此外,准二维钙钛矿对钙钛矿薄膜的形态也具有明显的改善作用,可代替反溶剂工程,简化工艺,满足钙钛矿的工业化生产要求。然而,由于绝缘的有机间隔阳离子导致的相对大的带隙和低的载流子迁移率,阻碍了载流子传输,准二维钙钛矿太阳能电池的效率仍然与三维钙钛矿相差较大。因此,对于准二维钙钛矿,必须对其特性和器件应用等进行进一步研究,实现器件性能的进一步优化。本文总结了准二维钙钛矿太阳能电池的研究进展,归纳了准二维钙钛矿的分子结构、准二维结构提升三维钙钛矿稳定性的方法和原理、准二维钙钛矿的相分布及其载流子传输特性,分析了准二维钙钛矿太阳能电池目前面临的问题并对其前景进行了展望,期望为制备高效稳定的准二维钙钛矿太阳能电池提供参考。

English Abstract

魏静, 王秋雯, 孙相彧, 李红博. 准二维钙钛矿太阳能电池的研究进展[J]. 中国光学. doi: 10.37188/CO.2020-0082
引用本文: 魏静, 王秋雯, 孙相彧, 李红博. 准二维钙钛矿太阳能电池的研究进展[J]. 中国光学. doi: 10.37188/CO.2020-0082
WEI Jing, WANG Qiu-wen, SUN Xiang-yu, LI Hong-bo. Research progress of quasi-two-dimensional perovskite solar cells[J]. Chinese Optics. doi: 10.37188/CO.2020-0082
Citation: WEI Jing, WANG Qiu-wen, SUN Xiang-yu, LI Hong-bo. Research progress of quasi-two-dimensional perovskite solar cells[J]. Chinese Optics. doi: 10.37188/CO.2020-0082
    • 钙钛矿太阳能电池(perovskite solar cells, PSCs)由于其低加工成本和高光电转换效率(power conversion efficiency, PCE)已成为最有前途的光伏技术之一[1]。三维钙钛矿结构通式为AMX3,每个A离子被一个由M和X离子组成的八面体[MX6]4−所包围,一个个八面体晶胞[MX6]4−紧密排列组合成为三维钙钛矿晶体,其中A位通常为有机阳离子或Cs+离子,M位通常为Pb2+或Sn2+离子,X位通常为Cl、Br或I等阴离子[2-7]

      钙钛矿材料具有优异的半导体性质,如高的光吸收系数、可调的带隙、低的激子结合能、长的载流子寿命和高的载流子迁移率等[8-12],表现出优异的光伏性能。钙钛矿太阳能电池的效率在过去十多年的发展中取得显著提高,由最初的3.81%[13]增长到现在25.2%[14]{, #150}的认证效率。随着钙钛矿太阳能电池的发展,三维(3D)钙钛矿不稳定性的问题越发突出,遭受着光和热稳定性差的困扰[15-18]。尽管研究人员为改善光伏性能做出了巨大努力并取得了显著进展,但三维钙钛矿材料固有的不稳定性导致PSCs的长期稳定性仍然很差,严重限制了其商业化发展[19-21]。因此,有必要在不牺牲电池效率的前提下进一步提高器件的稳定性,以实现未来的商业化应用[22-24]。近来,准二维(quasi-two-dimensional)钙钛矿在提高钙钛矿器件稳定性方面起到了关键作用,引起了人们的注意。除了显著提高的相稳定性、水氧稳定性等,准二维钙钛矿还具有制备工艺简单、能带结构可调和修饰三维钙钛矿界面等优势,展现了其应用于光伏器件的巨大前景[25-34]。本文系统地展示了准二维钙钛矿的性质及其在光伏应用方面的巨大潜力。针对准二维钙钛矿光伏器件的稳定性,文章主要从准二维结构设计提升钙钛矿相稳定性、水氧稳定性和释放晶格应力等几个方面对准二维钙钛矿及其光伏器件进行了综述;针对准二维钙钛矿的载流子传输特点,本文就薄膜工艺、衬底选择和器件结构设计等方面对准二维钙钛矿的载流子传输调控方法进行了详细阐述,并从相分布和晶体生长取向的调控方面简单介绍了几种提高载流子传输效率的方法。

    • 二维或准二维钙钛矿通过用稍大的有机胺离子替代或部分替代三维钙钛矿中的A位阳离子得到。稍大的有机胺阳离子将钙钛矿晶体沿<100>晶向“切开”,八面体[MX6]4-形成无机层,层中间为较大的有机胺层,无机层与有机胺层相互交替,依靠库仑力相互连接,形成了二维或准二维钙钛矿结构,包括Ruddlesden-Popper(RP)相和Dion-Jacobson(DJ)相。RP相钙钛矿包含两个单价阳离子(monocation),结构通式为A2Bn−1MnX3n+1;DJ相钙钛矿则包含一个二价阳离子(dication),结构通式为A’Bn−1MnX3n+1[32,35,36],其中A和A’代表插层的有机胺阳离子,n值表示共享角的八面体层的数量。目前,在准二维钙钛矿中,RP相钙钛矿展现出相对更高的稳定性[37],已获得>18%的高PCE[38],对其的研究也更为广泛,因此,本文接下来将主要讨论RP相钙钛矿。

      RP相钙钛矿A2Bn−1MnX3n+1中,n值用于调整材料和相关光伏电池的性能,也称为二维或准二维钙钛矿的层数。可以看出,当n=1时,有机胺层中的[MX6]4−八面体层仅有一层,称为二维钙钛矿结构;随着n增大到无穷时(n=∞),可以将有机胺层忽略,近似看成三维钙钛矿结构;n=1和n=∞之间(n≥2)的低维钙钛矿一般称为准二维钙钛矿结构[35],如图1(c)所示。容忍因子τ是衡量钙钛矿结构稳定性的重要参数,其定义为:

      $$ {\rm{\tau }} = \left( {{{\rm{R}}_{\rm{A}}} + {{\rm{R}}_{\rm{X}}}} \right)/\sqrt 2 \left( {{{\rm{R}}_{\rm{M}}} + {{\rm{R}}_{\rm{X}}}} \right) $$ (1)

      其中RA, RM, RX 分别代表钙钛矿AMX3中A, M, X各位点离子的半径,对于一个稳定的钙钛矿结构,各位点离子的半径受容忍因子的限制。准二维钙钛矿的层状结构放宽了容忍因子施加的阳离子尺寸的限制,使得大体积的有机胺阳离子可以容纳于无机层之间,因此可以使用多种有机阳离子。常见的有机胺阳离子包括正丁铵(n-C4H9NH3+, BA+)、异丁铵(iso-BA+)、聚乙烯亚铵((CH2CH2NH)n+, PEI+)、氨基戊酸((HOOC(CH2)4NH3)2+, AVA+)、胍盐(H2N(C=NH)NH2+, GA+)、苯乙铵(C6H5CH2CH2NH3+, PEA)等[36],如图1(a)所示。

      图  1  (a)常见的二维/准二维钙钛矿的有机胺阳离子;(b)不同n值BA2MAn-1PbnI3n+1及PEA2MAn-1PbnI3n+1的带隙排列[35, 36];(c)二维钙钛矿、准二维钙钛矿与三维钙钛矿的结构(RNH3+为有机胺阳离子)[36]

      Figure 1.  (a) Common organic amine cations of two-dimensional / quasi-two-dimensional perovskite; (b) bandgap arrangement of BA2MAn-1PbnI3n+1 and PEA2MAn-1PbnI3n+1 with different n values; (c) structure of two-dimensional perovskite, quasi-two-dimensional perovskite and three-dimensional perovskite.

    • 准二维钙钛矿薄膜的制备方法主要包括液相法、气相法、机械剥离等[37-39]

      液相法是目前使用最为广泛的制备方法。将反应物原材料(如金属卤化物、卤化有机物、卤化有机铵等)按照适当的比例混合溶解在有机溶剂(如DMF, DMSO等)中,旋涂(spin-coating)于衬底上,再通过加热退火使溶剂挥发,使得溶液过饱和而生长成钙钛矿晶体。液相法主要包括一步法、两步法、反溶剂法等[37,40,41]。一步法是将反应原料全部溶解于有机溶剂中,混合均匀后进行旋涂[42];两步法则是先旋涂金属卤化物和卤化有机铵混合溶液,随后再旋涂卤化有机物溶液,或者先旋涂金属卤化物溶液,再旋涂卤化有机铵和卤化有机物的混合溶液[43];反溶剂法是在溶液旋涂过程中,滴加不溶钙钛矿的溶剂(如氯苯、氯仿等),加速前驱液结晶。气相法是指将反应物原材料通过溅射、高温等方法,使其蒸发或升华为气相状态,再使气相分子反应,冷凝结晶生长钙钛矿晶体的方法,包括化学气相沉积(CVD)、气相外延(epitaxy)、磁控溅射等[37,44,45]。液相法合成准二维钙钛矿操作简单、工艺成熟、成本低廉,但较难精确控制钙钛矿的组成、相纯度和形态,而且容易引入缺陷。气相法则可以得到成膜均匀、缺陷较少的准二维钙钛矿,但对设备要求较高。因此,对准二维钙钛矿制备工艺的优化一直在继续研究。

      对于准二维钙钛矿,常用的表征方法包括X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见光光谱(UV-vis)、掠入射广角X射线散射(GIWAX)、光致发光图谱(PL)等。

    • 与三维钙钛矿相比,准二维钙钛矿晶体在结构、稳定性和载流子输运等方面具有显著不同的特点。准二维钙钛矿中引入的疏水性有机间隔阳离子不仅能够防止水分子渗透到钙钛矿晶格中,提升了钙钛矿的疏水性,同时,引入二维组分后,有机胺层内部存在的范德华力使得钙钛矿降解所需的去除卤化有机铵的能量增加[46],起到了阻碍钙钛矿中离子运动、迁移的作用,使得准二维钙钛矿太阳能电池展现出更稳定好的稳定性[47]。Dang[48]等人制备了BA2MAn-1PbnI3n+1 (n = 3或4)的片状和块状单晶并分析了其半导体性质,显示出准二维钙钛矿结构灵活,带隙宽度和激子结合能可随n值的变化而变化的特点。因此,可以通过改变n值、控制晶体取向等方式调整光电子的行为并引导器件性能[49]。BA2MAn-1PbnI3n+1和PEA2MAn-1PbnI3n+1钙钛矿带隙宽度随n值改变的变化趋势如图1(b)所示[35,36]

      但是,由于量子限域效应与增强的介电限制[50],准二维钙钛矿具有高达数百毫电子伏特的激子结合能(如PEA2PbI4的激子结合能约为200 meV[36]),激子在室温时能够稳定存在并被限制在由正的有机层和负的无机层组成的内建电场中,严重限制了器件中光生载流子的分离[51]。同时,准二维钙钛矿带隙较宽,光谱吸收范围窄,又由于绝缘的有机间隔阳离子导致的低的载流子迁移率,阻碍了光生载流子的有效传输,导致了较低的PCE。此外,准二维钙钛矿的薄膜制备工艺尚未发展成熟,结晶过程较难控制。用传统液相法制备的薄膜往往会形成不同n值的混相,且二维成分极易随机且平行于基板取向,影响载流子传输[36]。Dang[48]等人设计了单晶回溶技术制备准二维钙钛矿薄膜。他们首先制备了BA2MAn-1PbnI3n+1 (n = 3或4)的片状和块状单晶(如图2a-d),将单晶溶解后旋涂得到准二维钙钛矿薄膜。实验证明,这种单回溶技术能够有效控制准二维钙钛矿的相分布,实现薄膜中相的均匀分布。随着薄膜制备工艺、晶体取向调整、器件结构等各项优化,基于准二维钙钛矿的太阳能电池的PCE已经超过18%[52,53],器件稳定性有了明显的改善。但与三维钙钛矿相比,器件性能依然较差。表1 总结了几种典型的准二维钙钛矿光伏器件的性能和稳定性。这里,定义T80为器件PCE衰减至初始PCE的80%所需时间。需要注意的是,很多报道的器件在达到T80寿命之前即停止了测试。

      表 1  基于不同有机胺阳离子的准二维钙钛矿光伏器件的性能参数及其T80寿命

      2D组分器件结构PCE (%)稳定性(T80测试条件
      FEA[54]FTO/c-TiO2/m-TiO2/FEA2PbI4-FAPbI3/spiro-OMeTAD /Au22.2>1000 h1Sun, RH 40%,MPPT
      PEA[55]FTO/c-TiO2/m-TiO2/ Cs0.1FA0.74MA0.13PbI2.48Br0.39-PEA2Pb2I4/spiro-OMeTAD/Au20.08>800 h1Sun, 50°C,氩气,MPPT
      AVA[56]FTO/c-TiO2/m-TiO2/ HOOC(CH2)4NH3PbI4-MAPbI3/spiro-OMeTAD/Au14.6>200 h1Sun, 55°C, 氩气,MPPT
      GA[57]FTO/c-TiO2/GAMA3Pb3I10/spiro-OMeTAD/Au18.4860 h空气,MPPT
      VBA[58]ITO/TiO2/VAB-(MAPbBr3)0.15(FAPbI3)0.85/spiro-OMeTAD/Au20.216 h空气,MPPT
      BA[59]FTO/SnO2/PCBM/(BA)x(FA0.83Cs0.17)1-xPbn(I0.6Br0.4)3/spiro-OMeTAD/Au19.5T80=4000 h T80=1000 h1Sun, 封装;1Sun, 未封装,空气
      EDBE[60]FTO/SnO2/(EDBE)PbI4-(FA0.83Cs0.17)Pb(I0.8Br0.2)3/spiro-OMeTAD/Au21.06>3000 h空气
      3BBA[61]ITO/PTAA/3BBAI-MACl-PbI2/PCBM/Cr/Au18.2>2400 hRH 40%
      ThMA[34]ITO /SnO2/ThMA-FA PbI3-MAPbI3/spiro-OMeTAD/MoO3-Ag21.49>1800 h;>600 h空气, RH30-50%;N2, 1Sun
      5-AVA[62]FTO/bl-TiO2/mp-TiO2/(FAPbI3)0.88(CsPbBr3)0.12/(5-AVA)2PbI4/CuSCN/ Au16.75>1440 hRH 10%
      PEA[63]ITO / SnO2/FAPbI3-PEA2Pb2I4/spiro-OMeTAD/Ag or Au20.641362 h0.9Sun, 40°C,RH 50%,
      PEA[64]FTO/c-TiO2/m-TiO2/(FAPbI3)0.85(MAPbBr3)0.15-PEA2Pb2I4/spiro-OMeTAD/Au14.3≈1200 hRH 70%
      ThMA[65]ITO/PEDOT:PSS/ThMA2Man-1PbnI3n+1/PCBM/BCP/Ag15.42>1000 hN2
      PDA[66]ITO/PEDOT:PSS/ PDAMAn−1PbnI3n+1 /C60/BCP/Ag13.0>1000 h >100 hRH 85%;RH 85%, 70°C
      MA3Bi2I9[67]FTO/ c-TiO2/MA3Bi2I9-MAPbI3/spiro-OMeTAD/Au18.97>800 h空气
      PTA[68]FTO/c-TiO2/SnO2/PTAI-MAPbI3/spiro-OMeTAD/Ag20.6>500 hN2, 1Sun
      4FPEA[69]ITO/PTAA/(4FPEA)2MA4Pb5I16/PCBM/PEI/Ag17.3>500 hN2, 55°C
      F-PEA[70]FTO/c-TiO2/(F-PEA)2MA4Pb5I16/spiro-OMeTAD/Au13.64300 h70°C, 空气
      PEA[71]FTO/TiO2/(PEA)2Csn-1PbnI3n+1/PTAA/Au13.65>288 hN2 , 80°C,RH 25-30%
      PEA[41]FTO/NiO/MAPbI3-PEA2Pb2I4/(PCBM/PN4N)/Ag19.89≈240 hRH 20-30%
      BA[72]ITO / PTAA/MAPbI3-BA2Pb2I4/PCBM/C60/BCP/Cu19.56>100 h95°C
      CA2PbI4[73]ITO/PEDOT:PSS/ CA2PbI4-MAPbIxCl3-x/PCBM/Rhodamine 101/Au13.86>100 hRH63±5%
      OA[74]FTO/c-TiO2/ns-TiO2/OAI- (FAPbI3)0.95(MA PbBr3)0.05 /DM/Au22.03100 hRH 85%
      DA[74]FTO/c-TiO2/ns-TiO2/DAI- (FAPbI3)0.95(MA PbBr3)0.05 /DM/Au21.89100 hRH 85%
      (表格中,MPPT代表测试条件为最大功率点追踪测试(maximum power point tracking)。PEA为Phenethylammonium(苯乙基碘化胺);EDBE为2,2-(ethylenedioxy)bis(ethylammonium)(2,2-(乙二氧基)双(乙胺));BA为butylammonium(丁基胺);AVA为aminovaleric acid(氨基戊酸);5-AVA为5‐ammoniumvaleric acid(5-氨戊酸);OA为oleylammonium;DA为dodecylammonium(十二烷基胺);FEA为pentafluorophenylethylammonium(五氟苯基乙基胺);3BBA为3‐bromobenzylammonium(3-溴苄基胺);PTA为phenyltrimethylammonium(苯基三甲基胺);GA为guanidinium(胍盐);VBA为4-vinylbenzylammonium(4-乙烯基苄基胺);4FPEA为fluorine‐substituted phenylethlammonium(氟取代的苯基乙胺);ThMA为2‐thiophenemethy-lammonium(2-噻吩甲基甲胺);F-PEA为4-fluorophenethylammonium(4-氟苯乙胺);PDA为Propane-1,3-diammonium(丙烷-1,3-二胺);RH为相对湿度;T80为器件PCE衰减至初始PCE的80%所需时间。)

      稳定、高效是钙钛矿太阳能电池成功实现商业化的关键。尽管准二维结构可提高器件稳定性,但性能依然是限制其大规模发展的重要因素。到目前为止,准二维钙钛矿晶体的形成机制、载流子输运过程,特别是不同二维相在薄膜中的形成与分布机制仍未完全明确。因此,对于准二维钙钛矿,需要对其特性和器件设计进行进一步的研究和改进[75]

      图  2  (a-d) 准二维钙钛矿BA2MAn-1PbnI3n + 1片状和块状单晶的照片:(a, b) n=3,(c, d) n=4;(e) 单晶回溶技术制备BA2MAn-1PbnI3n + 1薄膜反应示意图[48]

      Figure 2.  (a-d) Pictures of the plate- and block-shaped single crystals of BA2MA2Pb3I10 (a and b) and BA2MA3Pb4I13 (c and d); (e) The formation processes of BA2MAn-1PbnI3n + 1 (n = 3 and 4) thin films based on their single-crystalline structures.

    • 钙钛矿晶体极差的稳定性严重限制了其工业化应用,例如被广泛研究的CH3NH3PbI3钙钛矿材料,由于甲铵有机阳离子(CH3NH3+,MA)的挥发性而遭受光、热和水氧稳定性差的困扰;基于甲脒(FA)的CH(NH2)2PbI3钙钛矿材料和基于Cs+的CsPbI3钙钛矿材料虽具有改善的光稳定性和热稳定性,但相稳定性较差。此外,钙钛矿的晶格形成能较小,外界条件(如水、氧等)的改变都会对钙钛矿的稳定性造成较大影响[76-78]。因此,有必要在不牺牲器件PCE的情况下进一步提高器件的稳定性,以实现未来的商业化应用。近来,准二维钙钛矿在提高钙钛矿器件稳定性方面起到了关键性的作用,引起了人们的注意。

    • 二维成分在三维钙钛矿中的引入能够有效改善其相稳定性。钙钛矿结构包含黑色的立方(α-)相,四方(β-)相和正交(γ-)相。容忍因子τ位于0.89-1之间时才会形成稳定的钙钛矿结构。对于APbI3来说,τ(Cs+)≈0.8,τ(MA+)位于0.91-0.99之间,τ(FA+)>1[2,3],所以可以看出,对于纯相CsPbI3和FAPbI3,其在室温下难以形成稳定的立方相钙钛矿结构[19,79,80];对于纯相MAPbI3,虽然其容忍因子较为合适,但是在室温下表现为β相,在327.4 K时才会从β相转变为α相[71]。因此,采取优化策略提升钙钛矿的相稳定性是十分必要的,常见的优化策略包括混合阳离子以及二维掺杂形成准二维钙钛矿结构。对于准二维钙钛矿,大的有机阳离子可以通过范德华相互作用将无机骨架分开,当器件暴露于周围环境时,准二维钙钛矿中的势垒大分子可以抑制组分分解和相变。多数研究证明,将PEA, BA, PEI等二维组分引入,三维钙钛矿的相稳定性明显提高[41,55,60,63]。Jin[81]等人使用OA(CH3(CH2)7NH3+)等长链胺盐作为表面封端配体,产生了基于二维结构的稳定的CsPbI3黑色光敏相。Huang[82]等人发现,在α-CsPbI3中混合少量磺基甜菜碱两性离子(Sulfobetaine Zwitterions)可以提升相稳定性并获得11.4%的PCE。Yuan[83]等人引入了适量的PEAI,并制造了准二维α-CsPbI3钙钛矿,PCE可达12.4%,极大地抑制了不良相变,相稳定性大大提高。

      在实际应用中,混合卤素的方法常被研究人员使用以调整钙钛矿材料的带隙宽度,通过改变X位卤素阴离子的比例,实现带隙调节,如在钙钛矿/硅串联太阳能电池中,理想的钙钛矿带隙在1.67至1.75 eV[84]之间,然而常用的三维钙钛矿带隙一般在1.5~1.6 eV[85]左右,所以常用溴离子部分替代碘离子,提高串联电池中钙钛矿材料的带隙[85]。但是,混合卤素钙钛矿在光照下存在严重的相分离现象,溴离子和碘离子移动并重新组合,形成富碘区域和富溴区域,准二维钙钛矿结构则可有效抑制相分离[86]。最近,Kim[87]等人使用硫氰酸盐(SCN)与碘的混合物开发了2D/3D混合宽带隙(1.68 eV)钙钛矿,他们证明了二维钝化层的电学性质、电荷传输特性等可以通过二维组分的阴离子工程来控制。利用这种方法,他们改善了钙钛矿光伏器件的性能、光稳定性和相稳定性,并获得了PCE高达26.7%的宽带隙钙钛矿/硅串联太阳能电池。该器件在最大功率点连续工作1000小时后,依然保持了> 80%的初始PCE,使用阴离子组分工程及准二维钙钛矿结构设计,可以扩展器件光稳定性,改善器件性能。

    • 除相稳定性外,钙钛矿的水氧稳定性也是一个极具挑战性的问题。由于大的有机铵阳离子往往具有疏水性,准二维钙钛矿的水氧稳定性要明显优于三维钙钛矿。Yang[63]等人利用PEA2PbI4二维钙钛矿稳定纯相的FA钙钛矿,他们发现PEA2PbI4与FAPbI3相互作用,促进了结晶过程中立方相钙钛矿的形成,且二维钙钛矿自发在三维钙钛矿的晶界(grain boundary)处形成,抑制了离子迁移;二维晶体中的有机大离子团的疏水性还保护了三维钙钛矿免受潮气影响,提升了器件的环境与操作稳定性(图3a-c)。Grätzel[54]等人利用这种准二维结构的设计,获得了PCE超过22%的2D /3D钙钛矿太阳能电池,并且器件具有较好的耐水、耐热性和操作稳定性。

      图  3  (a) 暴露于相对湿度80 ± 5%和20 ± 2 °C条件下,FAPbI3,2D钙钛矿修饰的FAPbI3和2D钙钛矿修饰的FA0.98Cs0.02PbI3钙钛矿薄膜随时间演变的照片[63];(b) 在相对湿度80 ±5%和20 ±2 °C条件下,600 nm处薄膜吸收光谱的演变(误差线表示每种条件下从三张膜中测得的吸光度的标准偏差)[63];(c) 器件中的多晶3D钙钛矿薄膜和2D钙钛矿薄膜的晶界(通过紫外光电子能谱(UPS)和Tauc图分析)[63];(d) 掺入20%PEA的FASnI3钙钛矿薄膜的掠入射广角X射线散射(GIWAXS)图像[40];(e) 储存在氮气气氛手套箱中的基于FASnI3和20%PEA掺杂的钙钛矿薄膜的未封装器件的PCE衰减示意图[40]

      Figure 3.  (a) Photos of the perovskite films incorporating bare FAPbI3, FAPbI3 with 2D perovskite and FA0.98Cs0.02PbI3 with 2D perovskite exposed to relative humidity (RH) of 80 ± 5% at 20 ± 2 °C for different times; (b) Evolution of the absorption of the films at 600 nm under RH 80 ± 5% at 20 ± 2 °C. The error bar indicates the standard deviation of the absorbance measured from the three films for each condition; (c) Schematics of the device incorporating polycrystalline a 3D perovskite film with 2D perovskite at grain boundaries; (d) GIWAXS images for 20% PEA film with Miller indices (orthorhombic system) of prominent peaks; (e) normalized PCE of the unencapsulated device based on FASnI3 and 20% PEA-doped perovskite film stored in a N2 atmosphere glovebox for over 100 h.

      除传统的铅基钙钛矿外,二维钙钛矿对器件水氧稳定性的提高效果,在水氧更为敏感的锡基钙钛矿中发挥了更大的作用。近年来,锡基钙钛矿由于其更低的毒性和与铅基钙钛矿类似的光电特性而成为新的研究热点。然而,锡基钙钛矿中的Sn2+极易与环境中的水氧反应,被氧化为Sn4+形成Sn空位,引起严重的薄膜缺陷[88],使得锡基钙钛矿薄膜水氧稳定差、制备工艺复杂,器件性能难以提高,因此,如何提升锡基钙钛矿薄膜的水氧稳定性是其发展的瓶颈问题[46,89,90]。准二维铅基钙钛矿在太阳能电池中的优异性能鼓励研究人员尝试准二维锡基钙钛矿。Liao[40]等人通过混合FA和PEA阳离子,实现了稳定的准二维锡基钙钛矿,其中PEA作为有机间隔层可有效保护中间的三维钙钛矿,隔绝水氧,大大提高了锡基钙钛矿在空气中的稳定性(图3d, e)。Cao等人[91]报告指出,基于二维结构的锡基BA2MAn-1SnnI3n+1钙钛矿太阳能电池与其三维对照组相比,可实现更高的性能和更好的稳定性。Wang[92]等人使用可移除的拟卤素NH4SCN作为结构调节剂来生长二维-准二维-三维锡基钙钛矿薄膜,由于这种结构中2D PEA2SnI4作为表面层的平行生长,显著增强了器件的空气稳定性,对应的器件效率提高到9.41%,在最大功率点连续工作600个小时可保持其初始性能的90%,表现出了明显改善的稳定性和光伏性能。

    • 残余应力(Residual Stresses)是指在去掉外部载荷后仍存留在材料内部的应力系统。由于热应力以及晶粒聚结、生长期间的外部条件等原因,残余应力常在钙钛矿薄膜中观察到,导致钙钛矿晶体结构的晶格畸变,影响器件稳定性[93]。通过调节薄膜内的残余应力,可以有效地调整材料的物理化学性质,从而进一步提升相应的器件性能和稳定性。Huang[94]等人以及Dauskardt[95]等人分别发现钙钛矿的内在不稳定性源于热退火引起的残余应变(Residual Strains),包括张应力(tensile stress)与压应力(compressive stress),其中张应力加速了晶体的降解。

      残余应变也会影响钙钛矿材料的稳定性,它是由于钙钛矿薄膜不均匀性而导致的晶格失配(lattice mismatches)所引起的[96]。Berger [97]等人和Zhang[98]等人基于第一性原理(DFT)理论计算,研究了应变调节及其对钙钛矿材料电子结构和光电性能的影响,表明应变调节是一种有效且相对容易实现的调制PSC性能的方法。所以,有必要开发适用的方法来调节钙钛矿薄膜的应力及应变[64,99]

      引入准二维钙钛矿是一种调节钙钛矿薄膜残余应变、降低薄膜中晶格应变的有效方法[96]。Snaith[59]等人将BA引入到FA0.83Cs0.17Pb(IyBr1-y)3钙钛矿中,实现了效率和稳定性的提高。他们观察到BA的引入会导致晶格常数的降低,这可能归因于钙钛矿晶体中的应变释放。陈棋课题组[100]通过在(FAPbI3)0.85(MAPbBr3)0.15钙钛矿薄膜上进行OAI和PEAI后处理实现了晶格重构(图4)。他们引入了不同的A位阳离子,调节沿薄膜厚度方向的残余应力分布,证明了不同的有机 A 位阳离子会导致不同的应力松弛行为。OAI/PEAI处理后形成的准二维钙钛矿成分有效地调节了界面间的相互作用,钙钛矿膜的表面残余应力可以释放约50%,得到了具有较少缺陷密度的均匀钙钛矿结构,从而改善了界面处的载流子传输并因此提高了器件性能。经过优化的器件不仅效率提高到了21.48%,而且还具有良好的湿度稳定性和耐外部应力性,在环境条件下经过1000小时后,未封装的器件仍保持初始效率的95%。残余应力的存在会加快钙钛矿的降解从而导致器件的不稳定性,释放残余应力能够获得具有较少缺陷密度的均匀钙钛矿结构,从而改善界面处的载流子传输并提高器件性能,不仅可以提高效率,还可以使器件获得良好的湿度稳定性和耐外部应力性[95,101-105]。今后的研究可以通过引入更有效的A位阳离子来消除表面残余应力,以通过调节不同有机组分之间的相互作用来设计新一代的杂化钙钛矿。

      图  4  (a)表面应力释放示意图:在(FAPbI3)0.85(MAPbBr3)0.15钙钛矿薄膜上进行OAI/PEAI后处理,通过晶格重构,松弛残余应力,调节沿薄膜厚度方向的残余应力分布,减轻晶格畸变程度;(b)引入PEA/OA释放残余应力机理示意图:低维钙钛矿成分主要在钙钛矿薄膜表面生成,在空间角度上提供了额外的结构灵活性,有效防止晶格变形;(c) 未封装钙钛矿太阳能电池在湿度16%-50%的空气中储存1000小时以上的长期稳定性测试(Reference指(FAPbI3)0.85(MAPbBr3)0.15钙钛矿;O-10指使用10×10-3 M浓度的OAI溶液后处理的(FAPbI3)0.85(MAPbBr3)0.15钙钛矿)[100]

      Figure 4.  (a) Schematic diagram of surface stress release: A post treatment process via lattice reconstruction on (FAPbI3)0.85(MAPbBr3)0.15 perovskites films was applied to modulate the residual stress distribution across film thicknesses in any direction, reducing the degree of lattice distortion; (b) Schematic diagram of the mechanism releasing residual stress by introducing PEA / OA: The 2D perovskite components mainly dwell at the surface of the perovskite thin films, which provides extra structural flexibility in the spatial perspective against lattice distortion; (c) The long-term stability test of the perovskite solar cells stored in air with a humidity of 16−50% for over 1000 h without encapsulation.

    • 在准二维钙钛矿晶体中,大有机胺离子的引入改善了钙钛矿的稳定性,然而,引入后载流子的传输问题成为发展光电性能的限制因素。研究发现,当准二维钙钛矿晶体沿基底垂直方向生长时,会自组装成不同n值的相,而非单一相,这种有序的n值分布提供了一种能量级联过程,可同时转移电子和空穴,一定程度上增强了载流子的传输,所以控制垂直排列结构已被证明是在准二维钙钛矿器件中增强光伏性能的主要方法。根据能级匹配关系,电子和空穴可以在不同相之间发生转移,电子由二维相转移到三维相,而空穴由三维相转移到二维相[106]。因此,Ma[66]等人及Zhang[107]等人认为,对于正向器件来说三维相沉积在底部更有利于电荷收集和传输,而对于反向器件来说二维相沉积在底部更有利。

      不同的工艺、器件结构及衬底等会对相分布有显著的影响。Dang[48]等人利用氧化钛介孔结构控制晶体取向,得到了垂直取向的准二维钙钛矿BA2MAn-1PbnI3n+1 (n = 3或4)(图5c-d)。然而氧化钛的光催化活性使得器件在光照下工作稳定性较差。之后在此基础上,Wei[23]等人提出了紫外光稳定的钛酸锌介孔结构并将其应用到钙钛矿太阳能电池中,器件工作稳定性和光稳定性都得到了显著提高;这一结构有望在准二维钙钛矿器件中发挥更大的作用,同时该方法工艺简单,对准二维钙钛矿的批量生产具有重要意义。Wang[108]等人详细研究了样品制备工艺对准二维钙钛矿晶体生长的影响及载流子在不同相之间的转移,他们通过控制晶体生长方向和晶体生长速率来调控准二维钙钛矿薄膜中相的分布。研究发现,利用乙酸乙酯作为反溶剂,晶体生长方向会发生变化,导致三维相生长在底部而二维相生长在表面;进一步发现通过加入CH3NH3Cl和DMSO溶剂,可以延缓晶体生长速率,从而提高相纯度(图5a)。随后,研究人员利用不同条件下得到的薄膜制备了太阳能电池,发现不同n值相纯度高的薄膜制备得到的器件效率最高,同时也证明了正向和反向器件的效率与晶体生长方向紧密相关(图5b)。Zhang[107]等人则引入真空极化(Vacuum poling)处理工艺,在结晶过程中控制形核,使不同n值的纳米板(PEA2MAn-1PbnI3n + 1)排列均匀,这种均匀分布可以通过精细的机械胶带剥离、PL/EDS等方法得到验证。通过均匀分布,瞬态吸收显示出10 ps内有效的载流子传输。此外,还得到了创纪录的82.4%的高填充因子,PCE为18.04%,储存8个月后,可保持96.1%的初始效率,并在80°C下保持97.7%的时间超过180小时,实现了卓越的稳定性。可见,工艺、衬底、器件结构的变化会影响不同n值的准二维钙钛矿纳米片的排列。未来可以根据器件的实际需要,通过改变工程策略来调节准二维钙钛矿晶体的生长方向、相分布以及载流子迁移,从而开发出高效且稳定的准二维钙钛矿型太阳能电池。然而,目前对于调控准二维钙钛矿相分布的理解、操纵和预测仍然远远不够,并且还处于早期探索阶段,控制准二维钙钛矿垂直分布的具体机理仍然未知,等待着进一步探索,这也对于未来准二维钙钛矿太阳能电池的进一步发展具有重要意义[109,110]

      图  5  (a) 原始BA2MA3Pb4I13钙钛矿薄膜、添加DMSO后钙钛矿薄膜的生长方向和相分布、添加反溶剂步骤后薄膜的生长方向[108];(b) 具有不同基底的常规(基底为氧化锡)和反式器件结构(基底为PEDOT:PSS)的示意图(红色圆球为空穴,蓝色圆球为电子)[108];(c, d) 介孔结构辅助控制BA2MAn-1PbnI3n + 1薄膜晶体取向示意图[48]

      Figure 5.  (a) Film growth direction and phase distribution of pristine BA2MA3Pb4I13 film, the film after adding DMSO and the film after adding antisolvent; (b) Schematics of conventional and inverted device architectures with different substrates (The red ball is the hole, and the blue ball is the electron); (c, d) The device architectures of BA2MAn-1PbnI3n + 1 (n = 3 and 4) solar cells based on single-crystalline precursors created with a modified hot-casting method.

    • 准二维钙钛矿的激子结合能比三维钙钛矿大得多,严重影响了电场中的激子解离。同时,绝缘间隔层的大有机阳离子抑制了相邻无机层之间的电荷传输,又由于较低的载流子迁移率、相对较大的带隙,导致了电荷传输受阻,使得准二维钙钛矿太阳能电池的性能仍然相对较差。所以更好地控制晶体取向、调控载流子传输显得尤为重要[34]

      沉积工艺对于晶体生长方向具有一定的影响[111]。Mohite[89]等人研究引入了“热旋涂(hot casting)”的制造方法,使得二维钙钛矿优先沿平面外方向垂直定向,有效地连接了电子和空穴选择电极层,从而改善电荷载流子传输和器件性能,PCE为12.5%,同时具有最小的磁滞和良好的稳定性。Li[112]等人设计了低压蒸汽辅助溶液法(Low-Pressure Vapor-Assisted Solution Process)制备多维有机金属卤化物钙钛矿。他们将掺杂有PEAI的碘化铅(PbI2)旋涂到基板上,然后在低压加热炉中与MAI蒸气反应得到多维钙钛矿薄膜。其中,PEAI的掺杂比例对晶体结构、薄膜表面形貌、光致发光光谱以及所得器件性能具有重大影响。Wu[113]等人在“热旋涂”工艺的基础上,针对BA2MA3Pb4I13二维钙钛矿太阳能电池提出了一种缓慢的后退火(slow post-annealing,SPA)工艺,通过该工艺可以实现17.26%的冠军PCE同时增强开路电压、短路电流和填充因子。结合光谱学和结构分析的研究表明,采用SPA处理可增强钙钛矿相(从底部附近的二维相到顶部附近的三维相)的晶体取向,从而促进载流子的迁移、提取并抑制太阳能电池中的电荷复合,且经SPA处理的器件在不封装的情况下,表现出令人满意的稳定性。Gao[114]等人和Ke[115]等人则使用溶剂工程技术(Solvent Engineering)处理二维钙钛矿薄膜,增强了电荷传输性能并有效改善形貌。

      对于沉积的衬底,Chen[116]等人揭示了一种机制,他们在各种基板上制成了BA2MA3Pb4I13薄膜,GIWAXS结果均显示出较强的优先垂直取向。随后他们进行了系统设计的原位GIWAXS实验,提出准二维钙钛矿BA2MA3Pb4I13的异质形核和生长发生在液-气界面,在此处形成了具有强垂直方向的顶壳(top-crust),由于BA分子的脂链保留在溶液环境中,所以在液-气界面的各向异性环境中就极有可能形成垂直取向的二维钙钛矿,而与基底选择无关,知道优先取向的起源后,就可以合理地调整具有相似薄膜形态的二维钙钛矿的垂直取向程度。又由于自上而下的生长机制,高质量的准二维钙钛矿薄膜可以沉积在从聚合物到金属氧化物的各种基材上。

      不同的溶剂对准二维钙钛矿薄膜的生长取向也有着一定程度的影响。Cao[91]等人报告指出,当使用二甲亚砜溶剂时,准二维锡基BA2MAn-1SnnI3n+1平行于基板生长;当使用N,N-二甲基甲酰胺溶剂时,则会翻转为垂直于基板生长(图6a)。

      对于不同的间隔阳离子,在准二维钙钛矿中也已经确定了由长链间隔阳离子介导的量子阱间的内部电荷转移或能量转移,由于这种转移过程强烈依赖于相邻量子阱之间的电子耦合,因此改变间隔阳离子可能是改善二维钙钛矿中电荷传输的另一种有效方法。Zheng[117]等人最近的研究工作表明,在二维钙钛矿中用较短的支化异丁基胺(即iso-BA)代替线性n-BA间距阳离子可以显著改善器件的光伏性能,且与n-BA对应物相比,iso-BA钙钛矿薄膜的平面外电荷载流子迁移率增加。他们通过使用瞬态吸收和时间分辨光致发光光谱,对n-BA和iso-BA钙钛矿中的光生电荷载流子动力学进行了详细研究,结果表明,间隔阳离子较短的iso-BA钙钛矿中量子阱之间的电荷转移比n-BA钙钛矿中的快。此外,在iso-BA钙钛矿中,电子和空穴的电荷迁移更加平衡,从而防止了可能的电荷积累。结果表明,较短间隔的阳离子大大促进了相间电荷/能量转移,从而防止了由于电子与空穴之间的转移速率不平衡而导致的电荷积累。此外,更短的间隔阳离子可确保激子有效地从二维相迁移到三维相。Chen[34]等人则成功地证明了使用2-噻吩甲基铵(ThMA)作为间隔阳离子可以有效地诱导晶体的生长和取向,并钝化陷阱态、阻碍离子迁移,从而延长了载流子寿命、降低了载流子复合损失,经过优化的器件的PCE可达21.49%(图6b)。Zhou[29]等人首次使用了PEA+和BA+的组合,他们研究了不饱和烷基胺和烷基胺阳离子之间的相互作用,同时将该发现推广到其他不饱和烷基胺阳离子,例如1-萘乙铵(C10H7(CH)CH3NH3+, NEA+)、烯丙基铵(CH2=CHCH2NH3+, ALA+),发现此类阳离子可改善跨吸收层的载流子传输;另一方面,长链烷基胺阳离子(如BA+)具有优异的结构柔性,有助于前体组装和定向晶体生长。此外,他们将实验结果和密度泛函理论(DFT)计算结合,证明了(BA,PEA)2(MA)3Pb4I13中PEA +可提供与PbI64-中的I-相互作用的π电子,通过电子分布迁移,有效地降低激子束缚能。

      图  6  (a) 2D BA2MA2Sn3I10材料的不同薄膜生长取向(当使用二甲亚砜溶剂时钙钛矿薄膜取向平行于基板,当使用N,N-二甲基甲酰胺溶剂时翻转为垂直方向)[91];(b) ThMA作为间隔阳离子的2D / 3D钙钛矿结构示意图(有机层插入3D钙钛矿中并垂直于基板定向生长)[34]

      Figure 6.  (a) Different film growth orientations of 2D BA2MA2Sn3I10 materials (2D perovskites thin film orientation is parallel to the substrate when dimethyl sulfoxide solvent is used for deposition. This orientation can be flipped to perpendicular when N,N-dimethylformamide solvent is used.); (b) Schematic diagram of the 2D / 3D perovskite structure with ThMA as spacer cations (organic layer inserted into 3D perovskite and oriented perpendicularly to the substrate).

    • 准二维钙钛矿具有良好的水氧稳定性和耐热稳定性,可以改善传统三维钙钛矿材料难以解决的不稳定性问题;准二维钙钛矿结合了二维钙钛矿稳定性好和三维钙钛矿性能优良的优势,是钙钛矿光伏器件突破目前寿命限制的新希望。同时,二维成分的引入对钙钛矿薄膜的形态有明显改善,使高质量薄膜的沉积能摆脱反溶剂工程等复杂步骤,对钙钛矿器件最终实现产业化意义重大。尽管目前准二维钙钛矿薄膜及其光伏器件存在载流子传输寿命低、扩散长度短、器件效率低等问题,但器件性能仍具有较大的提升空间。未来可以从以下几方面入手,进一步提高准二维钙钛矿太阳能电池的性能:①实现对材料结构和薄膜形态的有效控制,以指导高效的电荷传输;②提高器件稳定性和器件效率;③通过组分工程进一步提高2D / 3D混合材料的性能等;④探索控制准二维钙钛矿晶体的生长机制及其相分布和晶体取向的影响机理。

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