Effective Photon Management of Non-Surface-Textured Flexible Thin Crystalline Silicon Solar Cells

Thin crystalline silicon (c-Si) showing outstanding flexibility has been considered as an active material for flexible solar cells. However, an effective photon management should be developed for thin c-Si, which shows severe light absorption loss. Here, we introduce random inverted-pyramidal polydimethylsiloxane (RIP-PDMS) films on the surface of the thin c-Si solar cell to simultaneously secure high absorption and flexibility. Attaching the RIP-PDMS film on the front surface of the device can significantly reduce surface reflection; near-infrared light recycling can be further improved by attaching a metal-coated RIP-PDMS film on the rear surface of the device. Notably, thin c-Si solar cells with RIP-PDMS films have an efficiency of 18.4% and exhibit a constant efficiency during 1,000 repeated bending tests with a bending radius of 10 mm. Also, finite-difference time-domain simulations confirm that the RIP-PDMS films increase the light diffusion and optical path length inside the c-Si.