Review of progress in inorganic electron transport layers for perovskite solar cell applications
Source abstract
Abstract
Abstract Perovskite solar cells (PSCs) have emerged as a revolutionary photovoltaic technology, achieving remarkable power conversion efficiencies (PCEs) above 26.61%, while offering low-cost and scalable fabrication. Among the critical components of PSCs, the electron transport layer (ETL) plays a vital role in charge extraction, transport, and recombination suppression. This review provides a comprehensive analysis of recent advancements in inorganic ETLs, particularly focusing on widely studied materials such as TiO 2 , SnO 2 , and ZnO. While TiO 2 has historically been the benchmark ETL, challenges such as high-temperature processing and photocatalytic instability have led researchers to explore alternative materials. SnO₂ has gained prominence due to its superior electron mobility, low temperature processability, and excellent optical transparency, making it a strong candidate for high-performance PSCs. ZnO, with its high conductivity and facile synthesis, also shows promise, but faces stability concerns. The review further highlights the significance of surface modifications, doping strategies, and interface engineering to optimize charge transport dynamics and enhance device longevity. Additionally, we discuss emerging alternatives and future perspectives on scalable, cost-effective, and stable ETLs that could drive PSCs toward commercialization. By bridging fundamental material properties with device performance, this work provides insights into the next generation of high-efficiency and durable PSCs.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Perovskite Materials and Applications · Chalcogenide Semiconductor Thin Films · Solid-state spectroscopy and crystallography
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (100+)
Show source-provided references
1. A. Sharif et al., Exploring the impact of green technology, renewable energy and globalization towards environmental sustainability in the top ecological impacted countries. Geosci. Front. 15(6), 101895 (2024). https://doi.org/10.1016/j.gsf.2024.10189510.1016/j.gsf.2024.101895 ↗
2. N. Kannan, D. Vakeesan, Solar energy for future world: - a review. Renew. Sustain. Energy Rev. 62, 1092–1105 (2016). https://doi.org/10.1016/j.rser.2016.05.02210.1016/j.rser.2016.05.022 ↗
3. J.Y. Kim et al., High-efficiency perovskite solar cells. Chem. Rev. 120(15), 7867–7918 (2020). https://doi.org/10.1021/acs.chemrev.0c0010710.1021/acs.chemrev.0c00107 ↗
4. M. Liu, M.B. Johnston, H.J. Snaith, Efficient planar heterojunction perovskite solar cells by vapour deposition. Nature 501(7467), 395–398 (2013). https://doi.org/10.1038/nature1250910.1038/nature12509 ↗
5. H.-S. Kim et al., Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep. 2(1), 591 (2012). https://doi.org/10.1038/srep0059110.1038/srep00591 ↗
6. A. Kojima et al., Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131(17), 6050–6051 (2009). https://doi.org/10.1021/ja809598r10.1021/ja809598r ↗
7. Y. Huang et al., High-Efficiency Inverted Perovskite Solar Cells via In Situ Passivation Directed Crystallization. Advanced Materials, 2024. 36(41): p. 2408101 https://doi.org/10.1002/adma.20240810110.1002/adma.202408101 ↗
8. E.H. Anaraki et al., Highly efficient and stable planar perovskite solar cells by solution-processed tin oxide. Energy Environ. Sci. 9(10), 3128–3134 (2016). https://doi.org/10.1039/C6EE02390H10.1039/C6EE02390H ↗
9. M. Green et al., Solar cell efficiency tables (version 57). Prog. Photovoltaics Res. Appl. 29(1), 3–15 (2020). https://doi.org/10.1002/pip.337110.1002/pip.3371 ↗
10. M. Grätzel, Dye-sensitized solid-state heterojunction solar cells. MRS Bull. 30(1), 23–27 (2005)10.1557/mrs2005.4 ↗
11. S. Yun et al., New-generation integrated devices based on dye-sensitized and perovskite solar cells. Energy Environ. Sci. 11(3), 476–526 (2018). https://doi.org/10.1039/C7EE03165C10.1039/C7EE03165C ↗
12. U. Bach et al., Solid-state dye-sensitized mesoporous TiO2solar cells with high photon-to-electron conversion efficiencies. Nature 395(6702), 583–585 (1998). https://doi.org/10.1038/2693610.1038/26936 ↗
13. J. Cameron, P.J. Skabara, Organic electron transport materials. Beilstein J. Org. Chem. 20, 672–674 (2024). https://doi.org/10.3762/bjoc.20.6010.3762/bjoc.20.60 ↗
14. A.A. Said, J. Xie, Q. Zhang, Recent progress in organic electron transport materials in inverted perovskite solar cells. Small 15(27), 1900854 (2019). https://doi.org/10.1002/smll.20190085410.1002/smll.201900854 ↗
15. W. Zhang et al., Recent advance in solution-processed organic interlayers for high-performance planar perovskite solar cells. Adv. Sci. 5(7), 1800159 (2018). https://doi.org/10.1002/advs.20180015910.1002/advs.201800159 ↗
16. T. Zhang et al., Recent progress in improving strategies of inorganic electron transport layers for perovskite solar cells. Nano Energy 104, 107918 (2022). https://doi.org/10.1016/j.nanoen.2022.10791810.1016/j.nanoen.2022.107918 ↗
17. A.D. Racovita, Titanium dioxide: structure, impact, and toxicity. Int. J. Environ. Res. Public Health (2022). https://doi.org/10.3390/ijerph1909568110.3390/ijerph19095681 ↗
18. A.E. Shalan et al., Retraction note: A facile low temperature synthesis of TiO2nanorods for high efficiency dye sensitized solar cells. Appl. Phys. A 131(8), 634 (2025). https://doi.org/10.1007/s00339-025-08786-310.1007/s00339-025-08786-3 ↗
19. G. Guo, H. Zhang, The effect of morphology of ZnO particle on properties of asphalt binder and mixture. Int. J. Transp. Sci. Technol. 11(3), 437–454 (2022). https://doi.org/10.1016/j.ijtst.2021.05.00510.1016/j.ijtst.2021.05.005 ↗
20. G. Bai et al., High performance perovskite sub-module with sputtered SnO2electron transport layer. Solar Energy 183, 306–314 (2019). https://doi.org/10.1016/j.solener.2019.03.02610.1016/j.solener.2019.03.026 ↗
21. F. Ali, S. Gupta, A statistical design of experiments and structural characterization of ITO for perovskite solar cells. Appl. Phys. A 131(8), 648 (2025). https://doi.org/10.1007/s00339-025-08794-310.1007/s00339-025-08794-3 ↗
22. C. Luo et al., Perovskite Tandems: the Next Big Leap in Photovoltaic Technology. Advanced Materials, 2025. n/a(n/a): p. e08331 https://doi.org/10.1002/adma.20250833110.1002/adma.202508331 ↗
23. K.T. Tanko et al., Stability and reliability of perovskite photovoltaics: are we there yet? MRS Bull. 50(4), 512–525 (2025). https://doi.org/10.1557/s43577-025-00863-510.1557/s43577-025-00863-5 ↗
24. B. Zhang et al., Recent advances in tin halide perovskite solar cells: a critical review. J. Mater. Chem. A (2025). https://doi.org/10.1039/D5TA04568A10.1039/D5TA04568A ↗
25. M. Bissenova et al., Hybrid adsorption–photocatalysis composites: a sustainable route for efficient water purification. Mater. Renew. Sustain. Energy 14(2), 44 (2025). https://doi.org/10.1007/s40243-025-00319-510.1007/s40243-025-00319-5 ↗
26. D. Wang et al., Photocatalysis assisted solar-driven interfacial water evaporation: principles, advances and trends. Sep. Purif. Technol. 360, 130975 (2025). https://doi.org/10.1016/j.seppur.2024.13097510.1016/j.seppur.2024.130975 ↗
27. V.E. Madhavan et al., Copper thiocyanate inorganic hole-transporting material for high-efficiency perovskite solar cells. ACS Energy Lett. 1(6), 1112–1117 (2016). https://doi.org/10.1021/acsenergylett.6b0050110.1021/acsenergylett.6b00501 ↗
28. C.W. Myung, G. Lee, K.S. Kim, La-doped BaSnO3electron transport layer for perovskite solar cells. J. Mater. Chem. A 6(45), 23071–23077 (2018). https://doi.org/10.1039/C8TA08764D10.1039/C8TA08764D ↗
29. M. Zhu et al., Graphene-modified tin dioxide for efficient planar perovskite solar cells with enhanced electron extraction and reduced hysteresis. ACS Appl. Mater. Interfaces 11(1), 666–673 (2019). https://doi.org/10.1021/acsami.8b1566510.1021/acsami.8b15665 ↗
30. J. Han et al., Interfacial engineering of a ZnO electron transporting layer using self-assembled monolayers for high performance and stable perovskite solar cells. J. Mater. Chem. A 8(4), 2105–2113 (2020). https://doi.org/10.1039/C9TA12750J10.1039/C9TA12750J ↗
31. Y. Sun et al., In situ ligand-managed SnO2 electron transport layer for high-efficiency and stable perovskite solar cells. Adv. Funct. Mater. 34(51), 2410165 (2024). https://doi.org/10.1002/adfm.20241016510.1002/adfm.202410165 ↗
32. G. Yang et al., Effective carrier-concentration tuning of SnO2quantum dot electron-selective layers for high-performance planar perovskite solar cells. Adv. Mater. 30(14), 1706023 (2018). https://doi.org/10.1002/adma.20170602310.1002/adma.201706023 ↗
33. K. Xiao et al., Solution-processed monolithic all-perovskite triple-junction solar cells with efficiency exceeding 20%. ACS Energy Lett. 5(9), 2819–2826 (2020). https://doi.org/10.1021/acsenergylett.0c0118410.1021/acsenergylett.0c01184 ↗
34. Y. Zhao et al., Thick TiO2-based top electron transport layer on perovskite for highly efficient and stable solar cells. ACS Energy Lett. 3(12), 2891–2898 (2018). https://doi.org/10.1021/acsenergylett.8b0150710.1021/acsenergylett.8b01507 ↗
35. H. Niu et al., Magnetron sputtered ZnO electron transporting layers for high performance perovskite solar cells. Dalton Trans. 50(19), 6477–6487 (2021). https://doi.org/10.1039/D1DT00344E10.1039/D1DT00344E ↗
36. A. Uddin, H. Yi, Progress and challenges of SnO2 electron transport layer for perovskite solar cells: a critical review. Solar RRL (2022). https://doi.org/10.1002/solr.20210098310.1002/solr.202100983 ↗
37. Q. Jiang, X. Zhang, J. You, SnO2: A wonderful electron transport layer for perovskite solar cells. Small 14(31), 1801154 (2018). https://doi.org/10.1002/smll.20180115410.1002/smll.201801154 ↗
38. W. Hu et al., Low-Temperature In Situ Amino Functionalization of TiO2Nanoparticles Sharpens Electron Management Achieving over 21% Efficient Planar Perovskite Solar Cells. Adv. Mater. 31(8), 1806095 (2019). https://doi.org/10.1002/adma.20180609510.1002/adma.201806095 ↗
39. G. Yang et al., Recent progress in electron transport layers for efficient perovskite solar cells. J. Mater. Chem. A 4(11), 3970–3990 (2016). https://doi.org/10.1039/c5ta09011c10.1039/c5ta09011c ↗
40. A.K. Jena, A. Kulkarni, T. Miyasaka, Halide perovskite photovoltaics: background, status, and future prospects. Chem. Rev. 119(5), 3036–3103 (2019). https://doi.org/10.1021/acs.chemrev.8b0053910.1021/acs.chemrev.8b00539 ↗
41. Q. Dong et al., Improved SnO2electron transport layers solution-deposited at near room temperature for rigid or flexible perovskite solar cells with high efficiencies. Adv. Energy Mater. 9(26), 1900834 (2019). https://doi.org/10.1002/aenm.20190083410.1002/aenm.201900834 ↗
42. Q. Dong et al., Energetically favored formation of SnO2nanocrystals as electron transfer layer in perovskite solar cells with high efficiency exceeding 19%. Nano Energy 40, 336–344 (2017). https://doi.org/10.1016/j.nanoen.2017.08.04110.1016/j.nanoen.2017.08.041 ↗
43. Y. Chen et al., SnO2-based electron transporting layer materials for perovskite solar cells: a review of recent progress. J. Energy Chem. 35, 144–167 (2019). https://doi.org/10.1016/j.jechem.2018.11.01110.1016/j.jechem.2018.11.011 ↗
44. P. Zhang et al., Perovskite solar cells with ZnO electron-transporting materials. Adv. Mater. 30(3), 1703737 (2018). https://doi.org/10.1002/adma.20170373710.1002/adma.201703737 ↗
45. R. Keshtmand, M.R. Zamani-Meymian, N. Taghavinia, Improving the performance of planar perovskite solar cell using NH4Cl treatment of SnO2as electron transport layer. Surf. Interfaces 28, 101596 (2022). https://doi.org/10.1016/j.surfin.2021.10159610.1016/j.surfin.2021.101596 ↗
46. A. Kumar et al., Enhanced efficiency and stability of electron transport layer in perovskite tandem solar cells: challenges and future perspectives. Solar Energy 266, 112185 (2023). https://doi.org/10.1016/j.solener.2023.11218510.1016/j.solener.2023.112185 ↗
47. J.-X. Song et al., Low-temperature-processed metal oxide electron transport layers for efficient planar perovskite solar cells. Rare Met. 40(10), 2730–2746 (2021). https://doi.org/10.1007/s12598-020-01676-y10.1007/s12598-020-01676-y ↗
48. H. Soliman, A.S.H. Makhlouf, D. Rayan, Dual-function film of ZnO doped into CrNi black coatings as solar absorbent and corrosion resistant. Appl. Phys. A 130(12), 923 (2024). https://doi.org/10.1007/s00339-024-07961-210.1007/s00339-024-07961-2 ↗
49. S. Ali et al., Simulation of lead-free perovskite solar cells with improved performance. Crystals (2025). https://doi.org/10.3390/cryst1502017110.3390/cryst15020171 ↗
50. K.K. Sharma et al., (111) facet-engineered Sno2 as an electron transport layer for efficient and stable triple-cation perovskite solar cells. Sustain. Energy Fuels 9(11), 3102–3109 (2025). https://doi.org/10.1039/D5SE00339C10.1039/D5SE00339C ↗
51. M.S. Reza et al., A comprehensive investigation involving numerous HTL and ETL layers to design and simulate high-efficiency Ca3AsI3-based perovskite solar cells. Inorg. Chem. Commun. 172, 113647 (2025). https://doi.org/10.1016/j.inoche.2024.11364710.1016/j.inoche.2024.113647 ↗
52. F.L. Rahim et al., Computational study of highly efficient SnO 2 ETL-based inorganic perovskite solar cell. Przegląd Elektrotechniczny, 2024. 2024(11).10.15199/48.2024.11.18 ↗
53. A. Basit, I. Qasim, Optimizing solar cell and module design with SnO2-ETL and organometal-halide perovskite absorber: SCAPS-1D and PVSyst analysis. Wirel. Power Transf. (2025). https://doi.org/10.48130/wpt-0024-001510.48130/wpt-0024-0015 ↗
54. M. Meskini, S. Asgharizadeh, Performance simulation of the perovskite solar cells with Ti3C2MXene in the SnO2electron transport layer. Sci. Rep. 14(1), 5723 (2024). https://doi.org/10.1038/s41598-024-56461-z10.1038/s41598-024-56461-z ↗
55. H. Li et al., Photoferroelectric perovskite solar cells: principles, advances and insights. Nano Today 37, 101062 (2021). https://doi.org/10.1016/j.nantod.2020.10106210.1016/j.nantod.2020.101062 ↗
56. M.K. Hossain et al., An extensive study on multiple ETL and HTL layers to design and simulation of high-performance lead-free CsSnCl3-based perovskite solar cells. Sci. Rep. 13(1), 2521 (2023). https://doi.org/10.1038/s41598-023-28506-210.1038/s41598-023-28506-2 ↗
57. N.K. Elangovan et al., Recent developments in perovskite materials, fabrication techniques, band gap engineering, and the stability of perovskite solar cells. Energy Rep. 11, 1171–1190 (2024). https://doi.org/10.1016/j.egyr.2023.12.06810.1016/j.egyr.2023.12.068 ↗
58. T. Xue et al., Preparation of TiO2/SnO2 electron transport layer for performance enhancement of all-inorganic perovskite solar cells using electron beam evaporation at low temperature. Micromachines (2023). https://doi.org/10.3390/mi1408154910.3390/mi14081549 ↗
59. V.S. Katta et al., Deciphering the role of Er3+/Nd3+co-doping effect on TiO2as an improved electron transport layer in perovskite solar cells. Solar Energy 262, 111801 (2023). https://doi.org/10.1016/j.solener.2023.11180110.1016/j.solener.2023.111801 ↗
60. L. Chih-Wei et al., UV degradation mechanism of TiO2-based perovskite solar cells studied by pump-probe spectroscopy. in Proc.SPIE. 2020. https://doi.org/10.1117/12.255417410.1117/12.2554174 ↗
61. G.G. Njema, J.K. Kibet, A review of chalcogenide-based perovskites as the next novel materials: solar cell and optoelectronic applications, catalysis and future perspectives. Next Nanatechnol 7, 100102 (2025). https://doi.org/10.1016/j.nxnano.2024.10010210.1016/j.nxnano.2024.100102 ↗
62. M. Stramarkou et al., Fabrication of ZnO thin films doped with Na at different percentages for sensing CO2 in small quantities at room temperature. Sensors 25(9), 2705 (2025). https://doi.org/10.3390/s2509270510.3390/s25092705 ↗
63. Y. Taneja, D. Dube, R. Singh, Recent advances in elemental doping and simulation techniques: improving structural, photophysical and electronic properties of titanium dioxide. J. Mater. Chem. C 12(37), 14774–14808 (2024). https://doi.org/10.1039/D4TC02031F10.1039/D4TC02031F ↗
64. L.K. Tinoco Navarro, C. Jaroslav, Enhancing photocatalytic properties of TiO2 Photocatalyst and heterojunctions: A comprehensive review of the impact of biphasic systems in aerogels and xerogels Synthesis, Methods, and mechanisms for environmental applications. Gels. 9(12) (2023). https://doi.org/10.3390/gels912097610.3390/gels9120976 ↗
65. M.-M. Huo et al., Morphology and carrier non-geminate recombination dynamics regulated by solvent additive in polymer/fullerene solar cells. RSC Adv. 10(39), 23128–23135 (2020). https://doi.org/10.1039/D0RA03389H10.1039/D0RA03389H ↗
66. Y. Zhang, R. Dai, S. Hu, Study of the role of oxygen vacancies as active sites in reduced graphene oxide-modified TiO2. Phys. Chem. Chem. Phys. 19(10), 7307–7315 (2017). https://doi.org/10.1039/C7CP00630F10.1039/C7CP00630F ↗
67. X. Wang et al., Cerium oxide standing out as an electron transport layer for efficient and stable perovskite solar cells processed at low temperature. J. Mater. Chem. A 5(4), 1706–1712 (2017). https://doi.org/10.1039/C6TA07541J10.1039/C6TA07541J ↗
68. A.S. Yusuf et al., Effect of electron transport Layers, interface defect density and working temperature on perovskite solar cells using SCAPS 1-D software. East. Eur. J. Phys., 2024(1): pp. 332–341 https://doi.org/10.26565/2312-4334-2024-1-3110.26565/2312-4334-2024-1-31 ↗
69. A.S. Yusuf et al., A review of coating tin oxide electron transport layer for optimizing the performance of perovskite solar cells. Chemistry of Inorganic Materials 6, 100100 (2025). https://doi.org/10.1016/j.cinorg.2025.10010010.1016/j.cinorg.2025.100100 ↗
70. M. Shekargoftar et al., Low-temperature and rapid deposition of an SnO2layer from a colloidal nanoparticle dispersion for use in planar perovskite solar cells. Energy Technol. 9(5), 2001076 (2021). https://doi.org/10.1002/ente.20200107610.1002/ente.202001076 ↗
71. A. Beltrán et al., Thermodynamic argument about SnO2 nanoribbon growth. Appl. Phys. Lett. 83(4), 635–637 (2003). https://doi.org/10.1063/1.159483710.1063/1.1594837 ↗
72. Z. Li, P. Graziosi, N. Neophytou, Electron and hole mobility of SnO2from Full-Band Electron–Phonon and ionized impurity scattering computations. Crystals (2022). https://doi.org/10.3390/cryst1211159110.3390/cryst12111591 ↗
73. M.K. Hossain et al., Effect of various electron and hole transport layers on the performance of CsPbI3-based perovskite solar cells: a numerical investigation in DFT, SCAPS-1D, and WxAMPS frameworks. ACS Omega 7(47), 43210–43230 (2022). https://doi.org/10.1021/acsomega.2c0591210.1021/acsomega.2c05912 ↗
74. M. Simenas et al., Phase transitions and dynamics in mixed three- and low-dimensional lead halide perovskites. Chem. Rev. 124(5), 2281–2326 (2024). https://doi.org/10.1021/acs.chemrev.3c0053210.1021/acs.chemrev.3c00532 ↗
75. M.K. Hossain et al., A comprehensive study of the optimization and comparison of cesium halide perovskite solar cells using ZnO and Cu2FeSnS4 as charge transport layers. New J. Chem. 47(18), 8602–8624 (2023). https://doi.org/10.1039/D3NJ00320E10.1039/D3NJ00320E ↗
76. M.K. Rabchinskii et al., Rationalizing graphene–ZnO composites for gas sensing via functionalization with amines. Nanomaterials (2024). https://doi.org/10.3390/nano1409073510.3390/nano14090735 ↗
77. S. Yasmeen et al., Superior photodegradation of Bentazon and nile blue and their binary mixture using Sol–Gel synthesized TiO2 nanoparticles under UV and sunlight sources. Appl. Sci. (2025). https://doi.org/10.3390/app1504189910.3390/app15041899 ↗
78. D.R. Eddy et al., Heterophase polymorph of TiO2 (Anatase, Rutile, Brookite, TiO2B for efficient photocatalyst: fabrication and activity. Nanomaterials (Basel). 13(4) (2023). https://doi.org/10.3390/nano1304070410.3390/nano13040704 ↗
79. R. Ponte, E. Rauwel, P. Rauwel, Tailoring SnO2defect states and structure: reviewing bottom-up approaches to control size, morphology, electronic and electrochemical properties for application in batteries. Materials 16(12), 4339 (2023). https://doi.org/10.3390/ma1612433910.3390/ma16124339 ↗
80. H.E. Sánchez-Godoy et al., Situ ethanolamine ZnO nanoparticle passivation for perovskite interface stability and highly efficient solar cells. Nanomaterials (Basel). 12(5) (2022). https://doi.org/10.3390/nano1205082310.3390/nano12050823 ↗
81. G. Liu et al., Highly efficient and stable ZnO-based MA-free perovskite solar cells via overcoming interfacial mismatch and deprotonation reaction. Chem. Eng. J. 431, 134235 (2022). https://doi.org/10.1016/j.cej.2021.13423510.1016/j.cej.2021.134235 ↗
82. M. Haghighi et al., Low-temperature processing methods for tin oxide as electron transporting layer in scalable perovskite solar cells. Solar RRL 7(10), 2201080 (2023). https://doi.org/10.1002/solr.20220108010.1002/solr.202201080 ↗
83. Y. Zhao et al., Comprehensive study of Sol–Gel versus Hydrolysis–Condensation methods to prepare ZnO films: electron transport layers in perovskite solar cells. ACS Appl. Mater. Interfaces 9(31), 26234–26241 (2017). https://doi.org/10.1021/acsami.7b0483310.1021/acsami.7b04833 ↗
84. Y. Zhou, X. Li, H. Lin, To be higher and stronger—metal oxide electron transport materials for perovskite solar cells. Small 16(15), 1902579 (2020). https://doi.org/10.1002/smll.20190257910.1002/smll.201902579 ↗
85. T.-Y. Lee et al., Advances in core technologies for semiconductor manufacturing: applications and challenges of atomic layer etching, neutral beam etching and atomic layer deposition. Nanoscale Adv. 7(10), 2796–2817 (2025). https://doi.org/10.1039/D4NA00784K10.1039/D4NA00784K ↗
86. H. Lu et al., Identifying the optimum thickness of electron transport layers for highly efficient perovskite planar solar cells. J. Mater. Chem. A 3(32), 16445–16452 (2015). https://doi.org/10.1039/C5TA03686K10.1039/C5TA03686K ↗
87. X. Dong et al., The effect of ALD-Zno layers on the formation of CH3NH3PbI3 with different perovskite precursors and sintering temperatures. Chem. Commun. 50(92), 14405–14408 (2014). https://doi.org/10.1039/C4CC04685D10.1039/C4CC04685D ↗
88. Y. Lee et al., Efficient planar perovskite solar cells using passivated tin oxide as an electron transport layer. Adv. Sci. 5(6), 1800130 (2018). https://doi.org/10.1002/advs.20180013010.1002/advs.201800130 ↗
89. R.C. Ruiz-Ortega et al., Comprehensive analysis of CDS ultrathin films modified by the substrate position inside the reactor container using the CBD technique. ACS Omega 8(35), 31725–31737 (2023). https://doi.org/10.1021/acsomega.3c0215810.1021/acsomega.3c02158 ↗
90. K. Sun et al., Over 9% Efficient Kesterite Cu2ZnSnS4Solar Cell Fabricated by Using Zn1–xCdxS Buffer Layer. Adv. Energy Mater. 6(12), 1600046 (2016). https://doi.org/10.1002/aenm.20160004610.1002/aenm.201600046 ↗
91. M.H. Kumar et al., Flexible, low-temperature, solution processed ZnO-based perovskite solid state solar cells. Chem. Commun. 49(94), 11089–11091 (2013). https://doi.org/10.1039/C3CC46534A10.1039/C3CC46534A ↗
92. J.-Y. Chen et al., Low-temperature electrodeposited crystalline SnO2as an efficient electron-transporting layer for conventional perovskite solar cells. Sol. Energy Mater. Sol. Cells 164, 47–55 (2017). https://doi.org/10.1016/j.solmat.2017.02.00810.1016/j.solmat.2017.02.008 ↗
93. J. Ma et al., Highly efficient and stable planar perovskite solar cells with large-scale manufacture of E-beam evaporated SnO2toward commercialization. Solar RRL 1(10), 1700118 (2017). https://doi.org/10.1002/solr.20170011810.1002/solr.201700118 ↗
94. S.H. Im, A.J. Olasoji, Perspective Chapter: TiO2 Electron Transporting Layers for Perovskite Solar Cells, in Titanium Dioxide - Uses, Applications, and Advances, ed. by C. Montalvo Romero, C.A. Aguilar, E. Moctezuma (IntechOpen: Rijeka, Editors, 2024)
95. R. Banoth et al., Surface engineering of mesoporous-TiO2electron transport layer for improved performance of organic-inorganic perovskite solar cells via suppressing interface defects, enhancing charge extraction and boosting carrier transport. Colloids Surf A Physicochem. Eng. Aspects 676, 132075 (2023). https://doi.org/10.1016/j.colsurfa.2023.13207510.1016/j.colsurfa.2023.132075 ↗
96. S. Reghunath, D. Pinheiro, S.D. Kr, A review of hierarchical nanostructures of TiO2: advances and applications. Appl. Surf. Sci. Adv. 3, 100063 (2021). https://doi.org/10.1016/j.apsadv.2021.10006310.1016/j.apsadv.2021.100063 ↗
97. X. Wang et al., Electron Transport and Recombination in Photoanode of Electrospun TiO2Nanotubes for Dye-Sensitized Solar Cells. J. Phys. Chem. C 117(4), 1641–1646 (2013). https://doi.org/10.1021/jp311725g10.1021/jp311725g ↗
98. B. Yang et al., Low temperature synthesis of hierarchical TiO2nanostructures for high performance perovskite solar cells by pulsed laser deposition. Phys. Chem. Chem. Phys. 18(39), 27067–27072 (2016). https://doi.org/10.1039/C6CP02896A10.1039/C6CP02896A ↗
99. W.Q. Wu et al., Low-temperature solution-processed amorphous titania nanowire thin films for 1 cm2perovskite solar cells. ACS Appl. Mater. Interfaces 12(10), 11450–11458 (2020). https://doi.org/10.1021/acsami.9b1904110.1021/acsami.9b19041 ↗
100. W.-J. Lee, M. Alhoshan, W.H. Smyrl, Titanium dioxide nanotube arrays fabricated by anodizing processes: electrochemical properties. J. Electrochem. Soc. 153(11), B499 (2006). https://doi.org/10.1149/1.234709810.1149/1.2347098 ↗