A penetrated 2D/3D hybrid heterojunction for high-performance perovskite solar cells

Organic-inorganic hybrid lead halide perovskite solar cells (PSCs) attracted tremendous interest due to their excellent photovoltaic performance, but they still suffer from the poor long-term stability. Here, a penetrated 2D/3D heterojunction strategy is developed to stabilize the crystal structure at both the surface as well as grain boundaries and suppress non-radiative recombination. The organic halide with a large cation, namely dimethylammonium iodide (DMAI), was reported to achieve such a penetrated 2D/3D heterojunction through a simple post-treatment approach. Under this circumstance, the efficiency of Cs(0.05)FA(0.85)MA(0.10)Pb(I0.90Br0.10)(3) PSCs was improved from 19.83% to similar to 22% due to the significantly increased open-circuit voltage (V-oc). In addition, we demonstrated the versatility of such a strategy in Cs(0.05)FA(0.85)MA(0.10)Pb(I0.97Br0.03)(3) PSCs, leading to a champion efficiency approaching 23%. More importantly, the penetrated 2D/3D heterojunction can effectively protect the underlying 3D perovskite from moisture invasion. After ageing in air for 1000 hours, the device based on the 2D/3D heterojunction retained 80% of its initial efficiency, while the control device only maintained 57%.

Automated summary

A penetrated 2D/3D heterojunction strategy was developed to stabilize the crystal structure and improve the efficiency of organic-inorganic hybrid lead halide perovskite solar cells. By using organic halides like dimethylammonium iodide, a significant enhancement in performance was achieved. After 1000 hours of aging in air, the device with the 2D/3D heterojunction retained 80% of its initial efficiency, demonstrating superior stability compared to the control device.