Solution processed Mo doped SnO2 as an effective ETL in the fabrication of low temperature planer perovskite solar cell under ambient conditions.

Abstract Metal oxide electron transport layers play a crucial role on the extraction and transportation of charge carriers in organic-inorganic hybrid perovskite solar cells (PSCs). However, generally, fabrication of conductive metal oxide thin films requires high temperature annealing which is not compatible with roll to roll fabrication. It has been observed that a low temperature fabricated pristine metal oxide film exhibited low electrical conductivity, which has still prohibited to achieve high performance of device. Therefore, a low amount of metal doping within the pristine metal oxide films followed by low temperature thermal annealing is an effective approach to improve the electrical properties of the metal oxide thin films, and, thus, leading the higher performance of PSCs. Herein, we have developed a low temperature (180 °C) solution processed Molybdenum (Mo) doped SnO 2 (SnO 2 :Mo) as an efficient electron transport layer (ETL) for the fabrication of planer PSCs. The electrical conductivity of pristine film was significantly enhanced after the incorporation of a small amount of Mo dopant within the neat SnO 2 film, which could facilitate fast transportation of photo-generated charge carriers. Moreover, due to n-type Mo doping, Fermi level of resulting film was slightly shifted upwards, which could diminish charge recombination and, hence, improved the photovoltaic performance. The power conversion efficiency (PCE) for pristine SnO 2 and SnO 2 :Mo based PSCs was found to be 8.47% and 10.52%, respectively, when ETL and perovskite absorber films were processed in ambient conditions with the relative humidity range of 65%–75%. Compared to pristine SnO 2 , SnO 2 :Mo based PSC exhibited higher performance, which was attributed to the enhanced electrical properties of the resulting doped ETL thin film. Our results indicated that low temperature (180 °C) solution processed SnO 2 :Mo is a promising ETL for cost effective roll to roll fabrication of PSC. Graphical abstract Image 1 Highlights • Low temperature (180℃) solution processed Mo doped SnO 2 (SnO 2 :Mo) film as an efficient electron transport layer. • The XPS and SEM with elemental mapping proved the presence of Mo doping in the resulting film. • An optimal concentration of 1.0 mol% SnO 2 :Mo based PSC exhibited highest PCE of 10.52% under ambient conditions. [ABSTRACT FROM AUTHOR]