Efficient fully laser-patterned flexible perovskite modules and solar cells based on low-temperature solution-processed SnO 2 /mesoporous-TiO 2 electron transport layers

Efficient flexible perovskite solar cells and modules were developed using a combination of SnO 2 and mesoporous-TiO 2 as a fully solution-processed electron transport layer (ETL). Cells using such ETLs delivered a maximum power conversion efficiency (PCE) of 14.8%, which was 30% higher than the PCE of cells with only SnO 2 as the ETL. The presence of a mesoporous TiO 2 scaffold layer over SnO 2 led to higher rectification ratios, lower series resistances, and higher shunt resistances. The cells were also evaluated under 200 and 400 lx artificial indoor illumination and found to deliver maximum power densities of 9.77 μW/cm 2 (estimated PCE of 12.8%) and 19.2 μW/cm 2 (estimated PCE of 13.3%), respectively, representing the highest values among flexible photovoltaic technologies reported so far. Furthermore, for the first time, a fully laser-patterned flexible perovskite module was fabricated using a complete three-step laser scribing procedure (P1, P2, P3) with a PCE of 8.8% over an active area of 12 cm 2 under an illumination of 1 sun. [Figure not available: see fulltext.].