Optimal TiO2 Nanoparticles Electron Transporting Layer for Highly Efficient Ambient-atmosphere Fabricated Carbon-based Perovskite Solar Cells
Authors:   Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand, Khampa Warunee , Passatorntaschakorn Woraprom ,   Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand, Musikpan Wongsathon ,   Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand, Gardchareon Atcharawon ,   Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand, Ruankham Pipat ,   Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand,   Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand,   Thailand Center of Excellence in Physics (ThEP center), Ministry of Higher Education, Science, Research and Innovation, Bangkok, 10400, Thailand,   Research Unit for Development and Utilization of Electron Linear Accelerator and Ultrafast Infrared/Terahertz Laser, Chiang Mai University, Chiang Mai, 50200, Thailand, Wongratanaphisan Duangmanee ,   Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand,   Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand,   Thailand Center of Excellence in Physics (ThEP center), Ministry of Higher Education, Science, Research and Innovation, Bangkok, 10400, Thailand,   Research Unit for Development and Utilization of Electron Linear Accelerator and Ultrafast Infrared/Terahertz Laser, Chiang Mai University, Chiang Mai, 50200, Thailand
Published: November 2023

T he electron transporting layer (ETL) is a critical component for carbon-based planar Cs0.17FA0.83Pb(I0.83Br0.17)3 perovskite solar cells (C-PSCs), as it facilitates efficient charge transport between the perovskite material and the cathode. The low temperature processed TiO2 nanoparticles (TiO2 NPs) ETL (150°C) are widely employed in C-PSCs. However, the dispersion of commercial TiO2 NPs in colloid solution is often unstable, leading to particle agglomeration and sedimentation, which negatively affects the performance of C-PSCs. Therefore, it is crucial to achieve stable dispersion of TiO2 NPs in colloid solution before their application as ETL in C-PSCs. Furthermore, the surface properties of the TiO2 ETL such as the uniformity of film significantly impact the overall performance of C-PSCs. The objective of this study was to optimize the TiO2 ETL by investigating the dispersion of TiO2 NPs and varying their concentration in the solution for applying in ambient-atmosphere fabricated C-PSCs. The TiO2 NPs were dispersed in different solvents, including isopropanol, ethanol, and water. As a result, ethanol was the most effective solvent for dispersing TiO2 NPs, demonstrating the best dispersion stability. The concentration of TiO2 NPs in ethanol was then varied between 10-70 mg/ml. The results showed that the optimal concentration was 50 mg/ml, as it produced a high-quality ETL with a more uniform TiO2 film. This optimized TiO2 ETL in C-PSCs resulted in the highest power conversion efficiency (PCE) of 13.10% with FF, VOC, and JSC values of 65.50%, 1.02 V, and 19.52 mA/cm2, respectively.