• Laser & Optoelectronics Progress
  • Vol. 61, Issue 5, 0516002 (2024)
Yupeng Cui, Jue Gong, and Mingzhen Liu*
Author Affiliations
  • School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China
  • show less
    DOI: 10.3788/LOP230905 Cite this Article Set citation alerts
    Yupeng Cui, Jue Gong, Mingzhen Liu. Regulation of SnO2 Electron Transport Layers for Perovskite Solar Cells[J]. Laser & Optoelectronics Progress, 2024, 61(5): 0516002 Copy Citation Text show less
    References

    [1] Park J, Kim J, Yun H S et al. Controlled growth of perovskite layers with volatile alkylammonium chlorides[J]. Nature, 616, 724-730(2023).

    [2] Ye Z Z, Wang F Z, Chen F et al. Wide band gap semiconductor optoelectronic materials and their applications[J]. Acta Optica Sinica, 42, 1716001(2022).

    [3] He J T, Lü Q N, Zhang M D et al. Narrow-band perovskite photodetector based on SPR and interference mode composite enhancement[J]. Chinese Journal of Lasers, 49, 2304004(2022).

    [4] Han Q, Liu H, Guo F Y et al. Research progress on Cs2AgBiBr6 halide double-perovskite solar cells[J]. Laser & Optoelectronics Progress, 60, 0700004(2023).

    [5] Qian Z Y, Chen L B, Wang J P et al. Manipulating SnO2 growth for efficient electron transport in perovskite solar cells[J]. Advanced Materials Interfaces, 8, 2100128(2021).

    [6] Liu R R, Wang L, Fan Y P et al. UV degradation of the interface between perovskites and the electron transport layer[J]. RSC Advances, 10, 11551-11556(2020).

    [7] Dkhissi Y, Meyer S, Chen D H et al. Stability comparison of perovskite solar cells based on zinc oxide and titania on polymer substrates[J]. ChemSusChem, 9, 687-695(2016).

    [8] Altinkaya C, Aydin E, Ugur E et al. Tin oxide electron-selective layers for efficient, stable, and scalable perovskite solar cells[J]. Advanced Materials, 33, 2005504(2021).

    [9] Roose B, Wang Q, Abate A. The role of charge selective contacts in perovskite solar cell stability[J]. Advanced Energy Materials, 9, 1803140(2019).

    [10] Ke W J, Fang G J, Liu Q et al. Low-temperature solution-processed tin oxide as an alternative electron transporting layer for efficient perovskite solar cells[J]. Journal of the American Chemical Society, 137, 6730-6733(2015).

    [11] Huang X P, Du J H, Guo X et al. Polyelectrolyte-doped SnO2 as a tunable electron transport layer for high-efficiency and stable perovskite solar cells[J]. Solar RRL, 4, 1900336(2020).

    [12] Luo Q, Ma H, Hao F et al. Carbon nanotube based inverted flexible perovskite solar cells with all-inorganic charge contacts[J]. Advanced Functional Materials, 27, 1703068(2017).

    [13] Wang Y, Duan C H, Li J S et al. Performance enhancement of inverted perovskite solar cells based on smooth and compact PC61BM: SnO2 electron transport layers[J]. ACS Applied Materials & Interfaces, 10, 20128-20135(2018).

    [14] Leijtens T, Eperon G E, Pathak S et al. Overcoming ultraviolet light instability of sensitized TiO2 with meso-superstructured organometal tri-halide perovskite solar cells[J]. Nature Communications, 4, 2885(2013).

    [15] Guo X D, Dong H P, Li W Z et al. Multifunctional MgO layer in perovskite solar cells[J]. ChemPhysChem, 16, 1727-1732(2015).

    [16] Ito S, Tanaka S, Manabe K et al. Effects of surface blocking layer of Sb2S3 on nanocrystalline TiO2 for CH3NH3PbI3 perovskite solar cells[J]. The Journal of Physical Chemistry C, 118, 16995-17000(2014).

    [17] Tiwana P, Docampo P, Johnston M B et al. Electron mobility and injection dynamics in mesoporous ZnO, SnO2, and TiO2 films used in dye-sensitized solar cells[J]. ACS Nano, 5, 5158-5166(2011).

    [18] Min H, Lee D Y, Kim J et al. Perovskite solar cells with atomically coherent interlayers on SnO2 electrodes[J]. Nature, 598, 444-450(2021).

    [19] Jiang Q, Zhao Y, Zhang X W et al. Surface passivation of perovskite film for efficient solar cells[J]. Nature Photonics, 13, 460-466(2019).

    [20] Anaraki E H, Kermanpur A, Steier L et al. Highly efficient and stable planar perovskite solar cells by solution-processed tin oxide[J]. Energy & Environmental Science, 9, 3128-3134(2016).

    [21] Jiang Q, Chu Z M, Wang P Y et al. Planar-structure perovskite solar cells with efficiency beyond 21%[J]. Advanced Materials, 29, 1703852(2017).

    [22] Yang D, Yang R X, Wang K et al. High efficiency planar-type perovskite solar cells with negligible hysteresis using EDTA-complexed SnO2[J]. Nature Communications, 9, 3239(2018).

    [23] Jang Y W, Lee S, Yeom K M et al. Intact 2D/3D halide junction perovskite solar cells via solid-phase in-plane growth[J]. Nature Energy, 6, 63-71(2021).

    [24] Christians J A, Schulz P, Tinkham J S et al. Tailored interfaces of unencapsulated perovskite solar cells for >1,000 hour operational stability[J]. Nature Energy, 3, 68-74(2018).

    [25] Idrissi S, Bahmad L, Benyoussef A. Electronic properties of the Rutile-type dioxide SnO2 material doped by sulfur element: DFT study[EB/OL]. https://arxiv.org/abs/2108.05156

    [26] Li S, Qin F, Peng Q et al. Van der waals mixed valence tin oxides for perovskite solar cells as UV-stable electron transport materials[J]. Nano Letters, 20, 8178-8184(2020).

    [27] Wang C L, Zhao D W, Grice C R et al. Low-temperature plasma-enhanced atomic layer deposition of tin oxide electron selective layers for highly efficient planar perovskite solar cells[J]. Journal of Materials Chemistry A, 4, 12080-12087(2016).

    [28] Abuhelaiqa M, Shibayama N, Gao X X et al. SnO2/TiO2 electron transporting bilayers: a route to light stable perovskite solar cells[J]. ACS Applied Energy Materials, 4, 3424-3430(2021).

    [29] Kílíç C, Zunger A. Origins of coexistence of conductivity and transparency in SnO2[J]. Physical Review Letters, 88, 095501(2002).

    [30] Baco S, Chik A, Yassin F M. Study on optical properties of tin oxide thin film at different annealing temperature[J]. Journal of Science and Technology, 4, 61-72(2012).

    [31] Luo Y, Zhu C T, Ma S P et al. Low-temperature preparation of SnO2 electron transport layer for perovskite solar cells[J]. Acta Physica Sinica, 71, 118801(2022).

    [32] Dalapati G K, Sharma H, Guchhait A et al. Tin oxide for optoelectronic, photovoltaic and energy storage devices: a review[J]. Journal of Materials Chemistry A, 9, 16621-16684(2021).

    [33] Yuan R H, Cai B, Lv Y H et al. Boosted charge extraction of NbOx-enveloped SnO2 nanocrystals enables 24% efficient planar perovskite solar cells[J]. Energy & Environmental Science, 14, 5074-5083(2021).

    [34] Zhao J J, Wei L Y, Liu J X et al. A sintering-free, nanocrystalline tin oxide electron selective layer for organometal perovskite solar cells[J]. Science China Materials, 60, 208-216(2017).

    [35] Roose B, Baena J P C, Gödel K C et al. Mesoporous SnO2 electron selective contact enables UV-stable perovskite solar cells[J]. Nano Energy, 30, 517-522(2016).

    [36] Xiong L B, Qin M C, Yang G et al. Performance enhancement of high temperature SnO2-based planar perovskite solar cells: electrical characterization and understanding of the mechanism[J]. Journal of Materials Chemistry A, 4, 8374-8383(2016).

    [37] Ke W J, Zhao D W, Cimaroli A J et al. Effects of annealing temperature of tin oxide electron selective layers on the performance of perovskite solar cells[J]. Journal of Materials Chemistry A, 3, 24163-24168(2015).

    [38] Dong Q S, Zhu C, Chen M et al. Interpenetrating interfaces for efficient perovskite solar cells with high operational stability and mechanical robustness[J]. Nature Communications, 12, 973(2021).

    [39] Zheng Z H, Li F M, Gong J et al. Pre-buried additive for cross-layer modification in flexible perovskite solar cells with efficiency exceeding 22%[J]. Advanced Materials, 34, 2109879(2022).

    [40] Yang L, Feng J S, Liu Z K et al. Record-efficiency flexible perovskite solar cells enabled by multifunctional organic ions interface passivation[J]. Advanced Materials, 34, 2201681(2022).

    [41] Li M H, Zhou J J, Tan L G et al. Multifunctional succinate additive for flexible perovskite solar cells with more than 23% power-conversion efficiency[J]. The Innovation, 3, 100310(2022).

    [42] Raiford J A, Boyd C C, Palmstrom A F et al. Enhanced nucleation of atomic layer deposited contacts improves operational stability of perovskite solar cells in air[J]. Advanced Energy Materials, 9, 1902353(2019).

    [43] Pasquarelli R M, Ginley D S, O'Hayre R. Solution processing of transparent conductors: from flask to film[J]. Chemical Society Reviews, 40, 5406-5441(2011).

    [44] Palos C M M, Mariño-Gámez A E, Acosta-González G E et al. Large-scale production of ZnO nanoparticles by high energy ball milling[J]. Physica B: Condensed Matter, 656, 414776(2023).

    [45] Qiu L B, Liu Z H, Ono L K et al. Scalable fabrication of stable high efficiency perovskite solar cells and modules utilizing room temperature sputtered SnO2 electron transport layer[J]. Advanced Functional Materials, 29, 1806779(2019).

    [46] Yoo J J, Seo G, Chua M R et al. Efficient perovskite solar cells via improved carrier management[J]. Nature, 590, 587-593(2021).

    [47] Baig H, Kanda H, Asiri A M et al. Increasing efficiency of perovskite solar cells using low concentrating photovoltaic systems[J]. Sustainable Energy & Fuels, 4, 528-537(2020).

    [48] Chao L F, Niu T T, Gao W Y et al. Solvent engineering of the precursor solution toward large-area production of perovskite solar cells[J]. Advanced Materials, 33, 2005410(2021).

    [49] Kavan L, Steier L, Grätzel M. Ultrathin buffer layers of SnO2 by atomic layer deposition: perfect blocking function and thermal stability[J]. The Journal of Physical Chemistry C, 121, 342-350(2017).

    [50] Correa Baena J P, Steier L, Tress W et al. Highly efficient planar perovskite solar cells through band alignment engineering[J]. Energy & Environmental Science, 8, 2928-2934(2015).

    [51] Xing Z, Xiao J J, Hu T et al. Atomic layer deposition of metal oxides in perovskite solar cells: present and future[J]. Small Methods, 4, 2000588(2020).

    [52] Aydin E, Troughton J, De Bastiani M et al. Room-temperature-sputtered nanocrystalline nickel oxide as hole transport layer for p-i-n perovskite solar cells[J]. ACS Applied Energy Materials, 1, 6227-6233(2018).

    [53] Mo Y P, Shi J, Zhou P et al. Efficient planar perovskite solar cells via a sputtered cathode[J]. Solar RRL, 3, 1900209(2019).

    [54] Kiyek V M, Birkhölzer Y A, Smirnov Y et al. Single-source, solvent-free, room temperature deposition of black γ-CsSnI3 films[J]. Advanced Materials Interfaces, 7, 2000162(2020).

    [55] Xiong L B, Guo Y X, Wen J et al. Review on the application of SnO2 in perovskite solar cells[J]. Advanced Functional Materials, 28, 1802757(2018).

    [56] Li Z, Klein T R, Kim D H et al. Scalable fabrication of perovskite solar cells[J]. Nature Reviews Materials, 3, 18017(2018).

    [57] Qarnain S S, Muthuvel S, Bathrinath S. Review on government action plans to reduce energy consumption in buildings amid COVID-19 pandemic outbreak[J]. Materials Today: Proceedings, 45, 1264-1268(2021).

    [58] Sansoni S, De Bastiani M, Aydin E et al. Eco-friendly spray deposition of perovskite films on macroscale textured surfaces[J]. Advanced Materials Technologies, 5, 1901009(2020).

    [59] Lee J W, Lee D K, Jeong D N et al. Control of crystal growth toward scalable fabrication of perovskite solar cells[J]. Advanced Functional Materials, 29, 1807047(2019).

    [60] Bishop J E, Routledge T J, Lidzey D G. Advances in spray-cast perovskite solar cells[J]. The Journal of Physical Chemistry Letters, 9, 1977-1984(2018).

    [61] Yuan W J, Liu X Z, Fang Z Q et al. The effect of different annealing temperature on transparent conductive SnO2 thin film by solution process[J]. Molecular Crystals and Liquid Crystals, 676, 44-49(2018).

    [62] Jung E H, Chen B, Bertens K et al. Bifunctional surface engineering on SnO2 reduces energy loss in perovskite solar cells[J]. ACS Energy Letters, 5, 2796-2801(2020).

    [63] Guo Y X, Lei H W, Wang C L et al. Reconfiguration of interfacial and bulk energy band structure for high-performance organic and thermal-stability enhanced perovskite solar cells[J]. Solar RRL, 4, 1900482(2020).

    [64] Jarzebski Z M, Marton J P. Physical properties of SnO2 materials: I. preparation and defect structure[J]. Journal of the Electrochemical Society, 123, 199(1976).

    [65] Liu Z Z, Deng K M, Hu J et al. Coagulated SnO2 colloids for high-performance planar perovskite solar cells with negligible hysteresis and improved stability[J]. Angewandte Chemie International Edition, 58, 11497-11504(2019).

    [66] Mulheran P A, Harding J H. The stability of SnO2 surfaces[J]. Modelling and Simulation in Materials Science and Engineering, 1, 39-43(1992).

    [67] Rong Y G, Hu Y, Mei A Y et al. Challenges for commercializing perovskite solar cells[J]. Science, 361, eaat8235(2018).

    [68] Lin S Y, Yang B C, Qiu X C et al. Efficient and stable planar hole-transport-material-free perovskite solar cells using low temperature processed SnO2 as electron transport material[J]. Organic Electronics, 53, 235-241(2018).

    [69] Jiang Q, Zhang X W, You J B. SnO2: a wonderful electron transport layer for perovskite solar cells[J]. Small, 14, 1801154(2018).

    [70] Farooq A, Hossain I M, Moghadamzadeh S et al. Spectral dependence of degradation under ultraviolet light in perovskite solar cells[J]. ACS Applied Materials & Interfaces, 10, 21985-21990(2018).

    [71] Bisquert J, Juarez-Perez E J. The causes of degradation of perovskite solar cells[J]. The Journal of Physical Chemistry Letters, 10, 5889-5891(2019).

    [72] Thampy S, Zhang B Y, Hong K H et al. Altered stability and degradation pathway of CH3NH3PbI3 in contact with metal oxide[J]. ACS Energy Letters, 5, 1147-1152(2020).

    [73] Mathiazhagan G, Seeber A, Gengenbach T et al. Improving the stability of ambient processed, SnO2-based, perovskite solar cells by the UV-treatment of sub-cells[J]. Solar RRL, 4, 2000262(2020).

    [74] Dai Z H, Yadavalli S K, Chen M et al. Interfacial toughening with self-assembled monolayers enhances perovskite solar cell reliability[J]. Science, 372, 618-622(2021).

    [75] Zhu Z L, Bai Y, Liu X et al. Enhanced efficiency and stability of inverted perovskite solar cells using highly crystalline SnO2 nanocrystals as the robust electron-transporting layer[J]. Advanced Materials, 28, 6478-6484(2016).

    [76] Singh A N, Kajal S, Kim J et al. Interface engineering driven stabilization of halide perovskites against moisture, heat, and light for optoelectronic applications[J]. Advanced Energy Materials, 10, 2000768(2020).

    [77] Choi K, Lee J, Kim H I et al. Thermally stable, planar hybrid perovskite solar cells with high efficiency[J]. Energy & Environmental Science, 11, 3238-3247(2018).

    [78] Ke W J, Zhao D W, Xiao C X et al. Cooperative tin oxide fullerene electron selective layers for high-performance planar perovskite solar cells[J]. Journal of Materials Chemistry A, 4, 14276-14283(2016).

    [79] Dong Q S, Li J W, Shi Y T et al. Improved SnO2 electron transport layers solution-deposited at near room temperature for rigid or flexible perovskite solar cells with high efficiencies[J]. Advanced Energy Materials, 9, 1900834(2019).

    [80] Méndez P F, Muhammed S K M, Barea E M et al. Analysis of the UV-ozone-treated SnO2 electron transporting layer in planar perovskite solar cells for high performance and reduced hysteresis[J]. Solar RRL, 3, 1900191(2019).

    [81] Jung K, Kim D H, Kim J et al. Influence of a UV-ozone treatment on amorphous SnO2 electron selective layers for highly efficient planar MAPbI3 perovskite solar cells[J]. Journal of Materials Science & Technology, 59, 195-202(2020).

    [82] Song J X, Zheng E Q, Bian J et al. Low-temperature SnO2-based electron selective contact for efficient and stable perovskite solar cells[J]. Journal of Materials Chemistry A, 3, 10837-10844(2015).

    [83] Bu T L, Li J, Zheng F et al. Universal passivation strategy to slot-die printed SnO2 for hysteresis-free efficient flexible perovskite solar module[J]. Nature Communications, 9, 4609(2018).

    [84] Tong G Q, Ono L K, Liu Y Q et al. Up-scalable fabrication of SnO2 with multifunctional interface for high performance perovskite solar modules[J]. Nano-Micro Letters, 13, 155(2021).

    [85] Zuo L J, Gu Z W, Ye T et al. Enhanced photovoltaic performance of CH3NH3PbI3 perovskite solar cells through interfacial engineering using self-assembling monolayer[J]. Journal of the American Chemical Society, 137, 2674-2679(2015).

    [86] Hou M H, Zhang H J, Wang Z et al. Enhancing efficiency and stability of perovskite solar cells via a self-assembled dopamine interfacial layer[J]. ACS Applied Materials & Interfaces, 10, 30607-30613(2018).

    [87] Azmi R, Hadmojo W T, Sinaga S et al. High-efficiency low-temperature ZnO based perovskite solar cells based on highly polar, nonwetting self-assembled molecular layers[J]. Advanced Energy Materials, 8, 1701683(2018).

    [88] Kim S Y, Cho S J, Byeon S E et al. Self-assembled monolayers as interface engineering nanomaterials in perovskite solar cells[J]. Advanced Energy Materials, 10, 2002606(2020).

    [89] Magomedov A, Al-Ashouri A, Kasparavičius E et al. Self-assembled hole transporting monolayer for highly efficient perovskite solar cells[J]. Advanced Energy Materials, 8, 1801892(2018).

    [90] Hui W, Yang Y G, Xu Q et al. Red-carbon-quantum-dot-doped SnO2 composite with enhanced electron mobility for efficient and stable perovskite solar cells[J]. Advanced Materials, 32, 1906374(2020).

    [91] Ulman A. Formation and structure of self-assembled monolayers[J]. Chemical Reviews, 96, 1533-1554(1996).

    [92] Ali F, Roldán-Carmona C, Sohail M et al. Applications of self-assembled monolayers for perovskite solar cells interface engineering to address efficiency and stability[J]. Advanced Energy Materials, 10, 2002989(2020).

    [93] Ramirez C, Yadavalli S K, Garces H F et al. Thermo-mechanical behavior of organic-inorganic halide perovskites for solar cells[J]. Scripta Materialia, 150, 36-41(2018).

    [94] Charalambides P G, Cao H C, Lund J et al. Development of a test method for measuring the mixed mode fracture resistance of bimaterial interfaces[J]. Mechanics of Materials, 8, 269-283(1990).

    [95] Brand V, Bruner C, Dauskardt R H. Cohesion and device reliability in organic bulk heterojunction photovoltaic cells[J]. Solar Energy Materials and Solar Cells, 99, 182-189(2012).

    [96] Thampy S, Xu W J, Hsu J W P. Metal oxide-induced instability and its mitigation in halide perovskite solar cells[J]. The Journal of Physical Chemistry Letters, 12, 8495-8506(2021).

    [97] Rolston N, Watson B L, Bailie C D et al. Mechanical integrity of solution-processed perovskite solar cells[J]. Extreme Mechanics Letters, 9, 353-358(2016).

    [98] Dai Z H, Yadavalli S K, Hu M Y et al. Effect of grain size on the fracture behavior of organic-inorganic halide perovskite thin films for solar cells[J]. Scripta Materialia, 185, 47-50(2020).

    [99] Gutwald M, Rolston N, Printz A D et al. Perspectives on intrinsic toughening strategies and passivation of perovskite films with organic additives[J]. Solar Energy Materials and Solar Cells, 209, 110433(2020).

    [100] Yadavalli S K, Dai Z H, Zhou H et al. Facile healing of cracks in organic-inorganic halide perovskite thin films[J]. Acta Materialia, 187, 112-121(2020).

    [101] Wu J H, Cui Y Q, Yu B C et al. A simple way to simultaneously release the interface stress and realize the inner encapsulation for highly efficient and stable perovskite solar cells[J]. Advanced Functional Materials, 29, 1905336(2019).

    [102] Kim J H, Lee I, Kim T S et al. Understanding mechanical behavior and reliability of organic electronic materials[J]. MRS Bulletin, 42, 115-123(2017).

    [103] Zhou Q W, Duan J L, Yang X Y et al. Interfacial strain release from the WS2/CsPbBr3 van der waals heterostructure for 1.7 V voltage all-inorganic perovskite solar cells[J]. Angewandte Chemie International Edition, 59, 21997-22001(2020).

    [104] Boyd C C, Cheacharoen R, Leijtens T et al. Understanding degradation mechanisms and improving stability of perovskite photovoltaics[J]. Chemical Reviews, 119, 3418-3451(2019).

    [105] Xue D J, Hou Y, Liu S C et al. Regulating strain in perovskite thin films through charge-transport layers[J]. Nature Communications, 11, 1514(2020).

    [106] Zhao J J, Deng Y H, Wei H T et al. Strained hybrid perovskite thin films and their impact on the intrinsic stability of perovskite solar cells[J]. Science Advances, 3, eaao5616(2017).

    [107] Zhou Q, He D M, Zhuang Q X et al. Revealing steric-hindrance-dependent buried interface defect passivation mechanism in efficient and stable perovskite solar cells with mitigated tensile stress[J]. Advanced Functional Materials, 32, 2205507(2022).

    [108] Bi H, Liu B B, He D M et al. Interfacial defect passivation and stress release by multifunctional KPF6 modification for planar perovskite solar cells with enhanced efficiency and stability[J]. Chemical Engineering Journal, 418, 129375(2021).

    [109] Xiong Z, Chen X, Zhang B et al. Simultaneous interfacial modification and crystallization control by biguanide hydrochloride for stable perovskite solar cells with PCE of 24.4%[J]. Advanced Materials, 34, 2106118(2022).

    [110] Hou Y, Chen X, Yang S et al. A band-edge potential gradient heterostructure to enhance electron extraction efficiency of the electron transport layer in high-performance perovskite solar cells[J]. Advanced Functional Materials, 27, 1700878(2017).

    [111] Rao H S, Chen B X, Li W G et al. Improving the extraction of photogenerated electrons with SnO2 nanocolloids for efficient planar perovskite solar cells[J]. Advanced Functional Materials, 25, 7200-7207(2015).

    [112] Wu W Q, Chen D H, Cheng Y B et al. Thin films of tin oxide nanosheets used as the electron transporting layer for improved performance and ambient stability of perovskite photovoltaics[J]. Solar RRL, 1, 1700117(2017).

    [113] Li Z P, Wang L, Liu R R et al. Spontaneous interface ion exchange: passivating surface defects of perovskite solar cells with enhanced photovoltage[J]. Advanced Energy Materials, 9, 1902142(2019).

    [114] Hang P J, Xie J S, Li G et al. An interlayer with strong Pb-Cl bond delivers ultraviolet-filter-free, efficient, and photostable perovskite solar cells[J]. iScience, 21, 217-227(2019).

    [115] Zhang M Y, Wu F M, Chi D et al. High-efficiency perovskite solar cells with poly(vinylpyrrolidone)-doped SnO2 as an electron transport layer[J]. Materials Advances, 1, 617-624(2020).

    [116] Park S Y, Zhu K. Advances in SnO2 for efficient and stable n-i-p perovskite solar cells[J]. Advanced Materials, 34, 2110438(2022).

    [117] Wu P F, Wang S R, Li X G et al. Advances in SnO2-based perovskite solar cells: from preparation to photovoltaic applications[J]. Journal of Materials Chemistry A, 9, 19554-19588(2021).

    [118] Roose B, Johansen C M, Dupraz K et al. A Ga-doped SnO2 mesoporous contact for UV stable highly efficient perovskite solar cells[J]. Journal of Materials Chemistry A, 6, 1850-1857(2018).

    [119] Wang S, Zhu Y, Liu B et al. Introduction of carbon nanodots into SnO2 electron transport layer for efficient and UV stable planar perovskite solar cells[J]. Journal of Materials Chemistry A, 7, 5353-5362(2019).

    [120] Akin S. Hysteresis-free planar perovskite solar cells with a breakthrough efficiency of 22% and superior operational stability over 2000 H[J]. ACS Applied Materials & Interfaces, 11, 39998-40005(2019).

    [121] Wu Z H, Wu J H, Wang S B et al. Multifunctional molecule of potassium nonafluoro-1-butanesulfonate for high-efficient perovskite solar cells[J]. Chemical Engineering Journal, 449, 137851(2022).

    [122] Li H T, Kang Z H, Liu Y et al. Carbon nanodots: synthesis, properties and applications[J]. Journal of Materials Chemistry, 22, 24230-24253(2012).

    [123] Wang Y, Duan C H, Zhang X L et al. Dual interfacial engineering enables efficient and reproducible CsPbI2Br all-inorganic perovskite solar cells[J]. ACS Applied Materials & Interfaces, 12, 31659-31666(2020).

    [124] Chen J Z, Zhao X, Kim S G et al. Multifunctional chemical linker imidazoleacetic acid hydrochloride for 21% efficient and stable planar perovskite solar cells[J]. Advanced Materials, 31, 1902902(2019).

    [125] Liu H F, Huang Z R, Wei S Y et al. Nano-structured electron transporting materials for perovskite solar cells[J]. Nanoscale, 8, 6209-6221(2016).

    [126] Song S, Kang G, Pyeon L et al. Systematically optimized bilayered electron transport layer for highly efficient planar perovskite solar cells (η = 21.1%)[J]. ACS Energy Letters, 2, 2667-2673(2017).

    [127] Mali S S, Patil J V, Arandiyan H et al. Reduced methylammonium triple-cation Rb0.05(FAPbI3)0.95(MAPbBr3)0.05 perovskite solar cells based on a TiO2/SnO2 bilayer electron transport layer approaching a stabilized 21% efficiency: the role of antisolvents[J]. Journal of Materials Chemistry A, 7, 17516-17528(2019).

    [128] Liu X P, Bu T L, Li J et al. Stacking n-type layers: effective route towards stable, efficient and hysteresis-free planar perovskite solar cells[J]. Nano Energy, 44, 34-42(2018).

    [129] Hu M M, Zhang L Z, She S Y et al. Electron transporting bilayer of SnO2 and TiO2 nanocolloid enables highly efficient planar perovskite solar cells[J]. Solar RRL, 4, 2070014(2020).

    [130] Wang P Y, Li R J, Chen B B et al. Gradient energy alignment engineering for planar perovskite solar cells with efficiency over 23%[J]. Advanced Materials, 32, 1905766(2020).

    [131] Ye J J, Li Y Z, Medjahed A A et al. Doped bilayer tin(IV) oxide electron transport layer for high open-circuit voltage planar perovskite solar cells with reduced hysteresis[J]. Small, 17, 2005671(2021).

    [132] Liu Q, Qin M C, Ke W J et al. Enhanced stability of perovskite solar cells with low-temperature hydrothermally grown SnO2 electron transport layers[J]. Advanced Functional Materials, 26, 6069-6075(2016).

    [133] Dagar J, Castro-Hermosa S, Lucarelli G et al. Highly efficient perovskite solar cells for light harvesting under indoor illumination via solution processed SnO2/MgO composite electron transport layers[J]. Nano Energy, 49, 290-299(2018).

    [134] Chen Y, Xu C, Xiong J et al. Benefits of fullerene/SnO2 bilayers as electron transport layer for efficient planar perovskite solar cells[J]. Organic Electronics, 58, 294-300(2018).

    [135] Tian C B, Lin K B, Lu J X et al. Interfacial bridge using a cis-fulleropyrrolidine for efficient planar perovskite solar cells with enhanced stability[J]. Small Methods, 4, 1900476(2020).