Jeong, Inyoung Park, Yun Hee Bae, Seunghwan Park, Minwoo Jeong, Hansol Lee, Phillip Ko, Min Jae 2024-01-20T00:30:14Z 2024-01-20T00:30:14Z 2021-09-03 2017-10 1944-8244 https://pubs.kist.re.kr/handle/201004/122150 The electron transport layer (ETL) is a key component of perovskite solar cells (PSCs) and must provide efficient electron extraction and collection while minimizing the charge recombination at interfaces in order to ensure high performance. Conventional bilayered TiO2 ETLs fabricated by depositing compact TiO2 (c-TiO2) and mesoporous TiO2 (mp-TiO2) in sequence exhibit resistive losses due to the contact resistance at the c-TiO2/mp-TiO2 interface and the series resistance arising from the intrinsically low conductivity TiO2 of TiO2. Herein, to minimize such resistive losses, we developed a novel ETL consisting of an ultrathin c-TiO2 layer hybridized with mp-TiO2, which is fabricated by performing one-step spin-coating of a mp-TiO2 solution containing a small amount of titanium diisopropoxide bis(acetylacetonate) (TAA). By using electron microscopies and elemental mapping analysis, we establish that the optimal concentration of TAA produces an ultrathin blocking layer with a thickness of similar to 3 nm and ensures that the mp-TiO2 layer has a suitable porosity for efficient perovskite infiltration. We compare PSCs based on mesoscopic ETLs with and without compact layers to determine the role of the hole-blocking layer in their performances. The hybrid ETLs exhibit enhanced electron extraction and reduced charge recombination, resulting in better photovoltaic performances and reduced hysteresis of PSCs compared to those with conventional bilayered ETLs. English American Chemical Society Solution-Processed Ultrathin TiO2 Compact Layer Hybridized with Mesoporous TiO2 for High-Performance Perovskite Solar Cells Article 10.1021/acsami.7b11901 1 ACS Applied Materials & Interfaces, v.9, no.42, pp.36865 - 36874 ACS Applied Materials & Interfaces 9 42 36865 36874 N scie scopus 000414115700041 2-s2.0-85032964820 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Science & Technology - Other Topics Materials Science Article ELECTRON-TRANSPORT LAYER HALIDE PEROVSKITES EFFICIENT TEMPERATURE STABILITY FILM electron transport layer TiO2 charge recombination solution process perovskite solar cell