Abstract

Organic photovoltaics represent a very promising technology for solar energy conversion due to the light weight, flexibility, low cost, and rapid energy payback time of this technology. Current performance records for single-junction devices can be exceeded by the use of tandem cell structures in which two cells are stacked on top of each other, thus absorbing a larger fraction of the incoming light [1, 2]. From the optical point of view, when designing such tandem devices it is essential to tailor the device structure paying attention to two main issues: first, the multilayer structure has to be designed so the electric field of the incoming light is maximized within the absorbing layers; second, the interconnecting layer (ICL) used to connect the two sub-cells in series needs to provide the adequate electron-hole recombination rate and has to be as transparent as possible not to hamper light absorption by the rear sub-cell. In this work, we present an optically optimized tandem cell employing a novel combination of materials in the ICL with which a fill factor (FF) of 76% and a power conversion efficiency (PCE) of 8.2% can be obtained.

© 2015 IEEE