Improved performance of mesoscopic perovskite solar cell using an accelerated crystalline formation method

Highly smooth organo-lead halide perovskite (OHP) films with less intra-granular defects are necessary to minimize the non-radiative carrier recombination in photovoltaic devices. Herein, a simple air-extraction anti-solvent deposition (AAD) technique is proposed to improve the quality of perovskite films. An air extraction process accompanied by anti-solvent washing helps to improve the morphology of perovskite, leading to smooth, homogeneous, compact, pin-hole free and densely packed films. Perovskite films with an average roughness of 5.01 nm, which is the smoothest morphology in mesoscopic-perovskite solar cell to the extent of our knowledge, high crystallinity, and a crystallite size in the range of ∼500 nm to 1 μm have been achieved. Average power conversion efficiency (PCE) of 16.99% for 15 cells and a best PCE of 17.70% with a high open circuit voltage of 1.075 and fill factor of 74.22% were achieved using the AAD approach without a glove box. The cells exhibit virtually no hysteresis. These efficiency values are approximately 37.68% higher than the cells fabricated using anti-solvent process without air-extraction, where an average efficiency of 12.34% was measured. This method demonstrates high reproducibility and can be employed for the large scale production of PSC at reduced cost.