Conjugated polyelectrolyte with potassium cations enables inverted perovskite solar cells with an efficiency over 20%

Abstract

Defect-passivation functional groups have been extensively explored in perovskite solar cells (PSCs) in recent years; however, most of these groups were organic, and the integration of inorganic functional groups with organic matrixes bearing other functions has rarely been reported. Here, to demonstrate the effectiveness of this integration, the combination of an inorganic group, K⁺ ion, and an organic conjugated polyelectrolyte (CPE) matrix which serves as a hole transporting material (HTM) is attempted. The resulting CPE material TB(K) presents much stronger abilities for defect-passivation and hole-extraction, and thus yields a much increased power conversion efficiency (PCE) of 20.01% and increased long-term stability when applied to inverted PSC devices compared with its control polymer TB(Na), where only the inorganic cations are varied from a defect-passivation group to a common one.