Host-guest complexation in wide bandgap perovskite solar cells

Wide bandgap hybrid halide perovskites are increasingly relevant in the fabrication of tandem solar cells. However, their efficiency and stability during operation are still limited by several factors, among which ion migration at the interface with charge-selective extraction layers is one of the most detrimental ones. Herein, we employ a host-guest complexation strategy to control interfacial ion migration by using dibenzo-21-crown-7 in wide bandgap hybrid halide perovskites based on methylammonium (MA) lead bromide. We demonstrate the capacity of the crown ether to affect the performances and stabilities of MAPbBr3 solar cells. As a result, we achieve power conversion efficiencies up to 5.9% with an open circuit voltage as high as 1.5 V, which is accompanied by stability over 300 h at 85 °C under nitrogen atmosphere, as well as more than 300 h at ambient temperature, maintaining ∼80% of initial performance. This represents a versatile strategy for wide bandgap photovoltaic devices.