A penetrated 2D/3D hybrid heterojunction for high-performance perovskite solar cells†
Abstract
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 Cs0.05FA0.85MA0.10Pb(I0.90Br0.10)3 PSCs was improved from 19.83% to ∼22% due to the significantly increased open-circuit voltage (Voc). In addition, we demonstrated the versatility of such a strategy in Cs0.05FA0.85MA0.10Pb(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%.