Light Makes Right: Laser Polishing for Surface Modification of Perovskite Solar Cells
Mayank Kedia, Monika Rai, Himanshu Phirke, Clara Aranda, Chittaranjan Das, Vladimir S. Chirvony, Stephan Boehringer, Małgorzata Kot, Mahdi Malekshahi Byranvand, Jan Ingo Flege, Alex Redinger, Michael Saliba
Abstract
Interface engineering is a common strategy for passivating surface defects to attain open circuit voltages ( V oc ) in perovskite solar cells (PSCs). In this work, we introduce the concept of polishing a perovskite thin-film surface using a nanosecond (ns) pulsed ultraviolet laser to reduce surface defects, such as dangling bonds, undesirable phases, and suboptimal stoichiometry. A careful control of laser energy and scanning speed improves the photophysical properties of the surface without compromising the thickness. Using laser polishing, a V oc of 1.21 V is achieved for planar PSCs with a triple cation composition, showing an improved perovskite/hole transport interface by mitigating surface recombination losses. We measure an efficiency boost from 18.0% to 19.3% with improved stability of up to 1000 h. The results open the door to a new class of surface modification using lasers for interface passivation in well-controllable, automated, scalable, and solvent-free surface treatments.