The light trapping enhancement of inverted polymer solar cells by introducing NaYF4 nanoparticles

Sodium yttrium fluoride (NaYF4) nanoparticles (NPs) have been used to enhance the performance of optoelectronic devices such as polymer solar cells (PSCs). In this paper, we propose and demonstrate short circuit density (Jsc) enhancement induced by scattering and up-conversion (UC) effect of NPs in PSCs. The NaYF4 NPs were doped in active layer, functioning as highly efficient additive for improving the light harvesting, which leads to significantly increased photocurrent and power conversion efficiency (PCE) of inverted PSCs. The absorption spectrum shows that the doping devices have much stronger absorption, which is in accord with IPCE and transmittance spectrum. The absorption and electric field profile of the devices with or without NaYF4 NPs were performed using finite difference time domain (FDTD) simulation. It is approved that the NaYF4 NPs result in the absorption improvement by scattering and UC effect.