Silver coordination-induced n-doping of PCBM for stable and efficient inverted perovskite solar cells

Abstract

The bidirectional migration of halides and silver causes irreversible chemical corrosion to the electrodes and perovskite layer, affecting long-term operation stability of perovskite solar cells. Here we propose a silver coordination-induced n-doping of [6,6]-phenyl-C₆₁-butyric acid methyl ester strategy to safeguard Ag electrode against corrosion and impede the migration of iodine within the PSCs. Meanwhile, the coordination between DCBP and silver induces n-doping in the PCBM layer, accelerating electron extraction from the perovskite layer. The resultant PSCs demonstrate an efficiency of 26.03% (certified 25.51%) with a minimal non-radiative voltage loss of 126 mV. The PCE of resulting devices retain 95% of their initial value after 2500 h of continuous maximum power point tracking under one-sun irradiation, and > 90% of their initial value even after 1500 h of accelerated aging at 85 °C and 85% relative humidity.

The bidirectional halide and silver migration cause irreversible chemical corrosion to electrodes and perovskite layer. Here, the authors employ 4,4’-dicyano-2,2’-bipyridine in the electron transport layer to coordinate silver and iodide, realizing stable solar cells with efficiency over 26%.