230 / 2022-02-15 16:27:58

Deepening the field-effect of homojunction by gradient doping for highly efficient perovskite solar cells with high hole transfer

nickel oxide, perovskite solar cells, interface, carrier transport, gradient-doped homojunction

Mineral Materials and Advanced Energy Materials > 8. New Energy Materials

Inverted perovskite solar cells (PSCs) have triggered enormous studies and have become a star structure on account of their negligible hysteresis effect. Despite this, the highest power conversion efficiency (PCE) has been boosted to 23.8% for inverted PSCs, which is still far from the reported champion PCEs of PSCs with conventional structure. Obviously, the energy levels mismatch between conventional hole transport layer (HTL) and the perovskite absorber layer should be mainly responsible for the above efficiency distance. Herein, a gradient-doped homojunction (GHJ) based on gradient cobalt doped NiO was fabricated and used as HTL of the inverted PSCs. This GHJ structure contains four layers multiple-homojunction, which constructed conveniently by gradient cobalt doped nickel oxide. The GHJ structure can accelerate charge separation and efficiently improve the hole transfer. Accordingly, planar inverted PSCs with GHJ structure achieve an efficiency of 20.48%, narrowing the efficiency gap of PSCs with conventional structure. Notably, the GHJ-based PSCs exhibit an excellent long-time stability with only a 6% efficiency decline for 360 h under full spectrum illumination in N2. Therefore, the GHJ configuration improves both long-time stability and efficiency of inverted PSCs, which will provide important insights into the commercialization of optoelectronic devices.