Ultrathin SnO2 electron transport layers for perovskite solar cells by combustion method at low temperature

Electron transport layers can collect photo-generated electrons and suppress interfacial recombination, which are crucial for efficient perovskite solar cells . Tin oxide is a suitable electron transport material for its wide bandgap, high electron mobility , low photocatalytic activity and appropriate energy band offsets. For the deposition of tin oxide layers, SnCl 2 precursor is usually used for the conventional solution spin-coating method. In this work, we developed an in-situ synthesized precursor, and ultrathin tin oxide layers were obtained by the combustion process at 150 °C. Furthermore, the devices with these tin oxide layers can achieve the PCE of 19.6%, while conventional tin oxide layers with SnCl 2 precursor lead to the PCEs of 16.9% and 14.9% with and without plasma treatment. This improvement can be related to the enhanced photoelectron collection and superior interfacial contact. This work provides a facile method for fabricating SnO 2 electron transport layers of perovskite solar cells at low temperature.