High photoelectric conversion efficiency and stability of carbon-based perovskite solar cells based on sandwich-structured electronic layers

The electron transport layer is one of the critical factors affecting the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). For this, we designed a SnO2/TiO2 (mesoporous structure)/SnO2 sandwich-structured electron transport layer, which is more conducive to the extraction of electrons and can effectively improve the short-circuit current of the devices. The obtained champion void-free transport layer carbon electrode devices had a PCE of 15.12 %, a short-circuit current of 20.45 mA/cm2, an open-circuit voltage of 1.11 V, and a fill factor of 67 %. The PCE remained above 75.02 % of its initial efficiency after 720 h in ambient conditions with humidity at 30–40 %. This work provides a reference strategy for improving the efficiency of the carbon-based PSCs.