Efficient perovskite solar mini-modules fabricated via bar-coating using 2-methoxyethanol-based formamidinium lead tri-iodide precursor solution

Abstract

In small-area perovskite solar cells, efficiencies of >25% have been achieved using an antisolvent dripping technique; however, it is not applicable for coatings on an industrial scale. Currently, largearea devices based on scalable perovskite coatings still show a very large gap with small- area devices. This means that a uniform perovskite coating and defect control on large-area devices are not as secure as they are on small devices. Here, we report the deposition of dense and uniform perovskite films using an air-knife-assisted bar-coating employing a perovskite [(FAPbI(3))(0.95)(MAPbBr(3))(0.05)] precursor solution dissolved in 2- methoxyethanol. A pinhole-free and homogeneous surface morphology was achieved by adding n-cyclohexyl-2-pyrrolidone to ensure a balance between rapid nucleation and slowed crystal growth in the precursor solution. By applying surface passivation with acetylcholine bromide and laser etching to thin layers, mini-modules with an aperture area of 31 cm(2) were fabricated, attaining an efficiency of >20% (17.53% in the efficiency certified by a quasi-steady-state protocol).