Uncompromising on Organic Solar Cells

Researchers developed a semi-transparent organic solar cell that achieves better efficiency and transparency than existing ones, according to a recent study in the Science and Technology of Advanced Materials (STAM).

Semi-transparent organic solar cells (OSCs) havepotential for providing low-cost, large-area energy conversion devices for various applications such as windows, roof covers and greenhouses. However, it is challenging to achieve semi-transparent OSCs with high power conversion efficiency (PCE) and high transparency at the same time. Usually, the active materials of OSCs consist of a binary blend of a visibly absorbing donor polymer and a fullerene acceptor. The average visible transmittance (AVT) of the cell can be increased by decreasing the binary film thickness; however, this goes at the expense of the PCE because less sunlight is absorbed by a thinner layer.

In a STAM study, a team led by Mohammed Makha from the Swiss Federal Institute for Materials Science and Technology bypassed this tradeoff between transparency and efficiency of OSCs by using a ternary mixture. In addition, they used a flexible and transparent top electrode that was applied via a lamination step. As an advantage, the lamination process is simple and compatible with roll-to-roll systems for OSC production from solution.