Recent Developments in Organic Tandem Solar Cells Toward High Efficiency

The demands of sustainable energy sources and depletion of conventional energy sources have accelerated the quest for attaining nontoxic and low-cost organic solar cells (OSCs). The intrinsic characteristics of organic semiconductor materials such as light weight, mechanical stability, tailorable bandgaps, and ease of solution processability on a large area with flexible devices provide new dimensions to the device engineers toward sustainable electronic technologies. The past two decades have witnessed an inspiring breakthrough of device efficiency by developing multijunction architectures. The significance of organic tandem solar cells (OTSCs) does not only elevate the efficiencies but also considerably reduces the absorption losses. Herein, the recent developments in OTSCs, starting from designing rules for OTSCs, followed by implementation of the interconnecting layer (ICL) structure, and issues regarding processing, light management, and engaging photoactive materials for constructing OTSCs, are comprehensively described. Finally, the conclusion and outlook for OTSCs are provided.