Surface passivation enables efficient and stable inverted perovskite solar cells by 6-(Trifluoromethyl)pyridine-3-amidinehydrochloride

The inverted p-i-n PSCs are gradually gaining more attention since they are generally more stable and can employ low-cost transport materials. However, the interfaces between the perovskite and the charge transport layers contribute to major power conversion efficiency (PCE) loss and instability. Here, we use a material of 6-(Trifluoromethyl)pyridine-3-amidinehydrochloride (CF3-PyFACl) to molecularly engineer the interface between the perovskite and electron transport layer. The interface modification results in suppressed nonradiative recombination, and improved interfacial contact. A PCE of 23.17 % is demonstrated, with open-circuit voltage (Voc) and fill factor (FF) of 1.169 V and 84.1 %, respectively. The unencapsulated device retains >80 % of the initial performance after 400 h continuous light soaking.