High efficiency flexible perovskite solar cells using superior low temperature TiO2

A process is developed to prepare a very dense TiO2 layer using magnetron sputtering at room temperature. It is found that the film is amorphous in nature, offering faster electron transport, reduced transfer resistance and better performance for electron extraction from the perovskite absorber layer. It is these superior electronic properties that makes it possible for us to achieve 15.07% efficiency flexible perovskite solar cells, on a respectably large area >10 mm(2). It is the highest efficiency reported to date for the flexible perovskite devices.