Semi-transparent Ultra-flexible Organic Photovoltaics via Thin Multilayer Electrodes

Abstract

The development of ultra-flexible metal electrode (UME) is an essential to expand the optical science and engineering capabilities of flexible optoelectronic devices. In application of functional devices, the in-depth studies on novel UME layer, including mechanical, optical, and electrical analysis are prerequisite. With nano-scale thickness modulation of Ag thin metal layer, we analyzed different thickness of deposited films. As a result, the deposited layer exhibits >80% transparency at 380-825 nm, and sheet resistance <12 ohm/square. In addition, their mechanical robustness was improved under 66% compressive stress with repetitive cycling test over 103. Because the UME has good mechanical stability with both high transmittance and conductivity, the suggested electrodes can be applied into organic photovoltaics (OPVs) as a bottom and top electrodes. The fabricated ultra-flexible semi-transparent OPVs shows highest average visible transmittance (AVT) of 30.1 % and power-conversion-efficiency (PCE) of 6.93 % with high mechanical durability over 1000 cycles, comparative to those of OPVs using ITO electrodes. The results show their great potentials of the ultra-flexible ST-OPV, facilitating the road to the future for a variety of applications.