Fully Solution Processed, Stable, and Flexible Bifacial Polymer Solar Cells

Photon capturing is an essential step for the operation of a solar cell. In this article, we develop a bifacial solar cell with characteristics of double-side photon collection, transparent appearance, mechanical flexibility, and facile processing. The whole device was fully fabricated by a spin-coating technique. A power conversion efficiency (PCE) as high as 2.46% has been achieved using the most prominent photoactive material, poly(3-hexylthiophene):(6, 6)-phenyl C61 butyric acid methyl ester (P3HT:PCBM). The bifacial solar cell can retain 92% of its original PCE after 350 cyclic bending cycles at bending radii of 7.4 mm. In addition to the mechanical instability of the device, photochemical degradation is partially involved in the device operation. We believe that our device with its promising mechanical, physical, and processing features can serve as an essential power element to be integrated with other technologies for the next-generation self-powered technology.