LAUSR

Abstract For typical planar perovskite solar cell, an electron transporting layer (ETL) plays an important role in extracting electrons from a perovskite layer and blocking electron-hole recombination at the perovskite/conductive substrate interface. To date, TiO 2 or ZnO ETLs are mainly adopted in both forms of film and nanostructure due to their ease of preparation. Nevertheless, the photoinstability of TiO 2 and thermal instability of ZnO/perovskite interface remain the major challenges limiting their potential commercialization. Herein, we demonstrate an effective in situ template self-etching ( i TSE) strategy to grow the novel hollow domed SnO 2 nanotubes array with ZnO nanorods as sacrifice templates and the growth mechanism of such SnO 2 nanotubes has been proposed based on a series of controllable experiments. Using such SnO 2 nanotube as ETL for perovskite solar cell demonstrates a high photocurrent density of 15.9 mA/cm 2 at a based-voltage of 760 mV, leading to a stable power conversion efficiency of 12.1% over 1000 s under the simulated AM 1.5G one sun illumination. This work highlights the importance of the ETL material selection and provides insights into achieving an ideal ETL/substrate homojunction to facilitate electron transporting.