Improved performance of polymer/ZnO nanorod hybrid solar cells by slow drying of the photoactive layer

The slow drying of the photoactive layer in polymer/ZnO nanorod hybrid solar cells is studied as a way to improve device performance. The power conversion efficiency can be further improved to 3.05% with an enhanced fill factor of 55% by slowing the spin coating rate of photoactive layer. With the slower spin coating rate, the films of photoactive layer are thicker, and the polymer chains have longer time to self-organize and more effectively infiltrate into ZnO nanorod spacing, resulting in the higher crystallinity of polymer and light harvesting without sacrificing the carrier transportation.