Lengthening the polymer solidification time to improve the performance of polymer/ZnO nanorod hybrid solar cells

Lengthening the polymer solidification time in the inverted configuration of polymer/ZnO nanorod hybrid solar cells is studied as a way to improve device performance. As the polymer solidification time is lengthened by lowering the spin-coating rate of the photoactive layer, the photoactive layer becomes thickened, and the polymer chains have enough time to self-organize and effectively infiltrate into ZnO nanorod spacing. While the thickness of the photoactive layer is increased to 400 nm accompanying self-organized polymer, the power conversion efficiency of the device is improved to 3.58% with an enhanced fill factor of 58%. The 400 nm film is composed of the highly ordered polymer and the ZnO nanorod arrays, resulting in light harvesting without decreasing the possibility for charge transport.