Indium tin oxide-free perovskite solar cells with high flexibility and mechanical stability based on the ultrathin Au electrodes

摘要

Flexible perovskite solar cells (pero-SCs) have drawn much attention due to their high efficiency and low cost. Indium tin oxide (ITO) and fluorine-doped SnO_2 as the most commonly used transparent electrodes in pero-SCs, unfortunately, exhibit poor mechanical stability in flexible devices. We demonstrate flexible pero-SCs based on an ultrathin Au electrode with perfect performance of transmittance, conductivity, and mechanical stability. The ultrathin Au electrode with the thickness of 7 nm is prepared on the SU-8/Ca modified substrate, and the Volmer-Weber growth mode of deposited metal film has been suppressed successfully by the chemical and physical bonding from the SU-8/Ca hybrid modification layer. The ITO-free flexible pero-SCs based on ultrathin Au electrodes achieve the power conversion efficiency of 11.44%, and nearly 82% of the initial efficiency remains after approximately 2400 bending cycles, demonstrating the high flexibility and mechanical stability of the Ultrathin Au electrode as well as the ITO-free pero-SCs.