Nanoimprinting of Perovskite Layer for Light-Harvesting Effect in Photovoltaic Devices.

A light-harvesting effect was successfully achieved in photovoltaic devices by the structuring of an active perovskite layer through nanoimprinting. This was done by transforming a commercial CD-R pattern into a polydimethylsiloxane (PDMS) film. The latter was then used for replicating the perovskite layers under increased pressures and temperatures. The Young's modulus of the PDMS film was regulated by the mixing ratio of the base and curing agents, and the average height of the pattern was reported for an optimal 5:1 base-to-curing agent ratio. Under these conditions, the replication efficiency reached 80% at a pressure of ~ 4.9 kPa. To investigate the manner in which the structuring of these patterned perovskite layers affects optoelectronic devices, we incorporated them into photovoltaic cells. This resulted in improved J–V characteristics, as observed from an increase in both fill factor (FF) and short circuit current density (J_sc), from 73.20 to 76.35% and from 12.853 to 15.532 mA cm⁻², respectively. The increase in FF was attributed to a large contact area between the perovskite and electron transport layers, while the increase in J_sc was due to the enhanced light-trapping of the periodic grating patterns of the perovskite layer. [ABSTRACT FROM AUTHOR]