Room-temperature solution-processed amorphous NbOx as an electron transport layer in high-efficiency photovoltaics

Preparation of high-quality amorphous oxide semiconductor (AOS) films by wet chemical routes at low temperature (<100 degrees C) remains difficult. Here, we conducted systematic research for the low-temperature fabrication of AOS by a solution route using amorphous NbOx as an example. Perovskite solar cells (PSCs) based on a solution-processed amorphous ETL obtain a high power conversion efficiency of up to 19.09%, which is much higher than that of the PSCs using solution-processed AOS ETLs and even compare favourably with those using vacuum-processed ETLs.