Hybrid solar cells based on poly(3-hexylthiophene) and electrospun TiO2 nanofibers modified with CdS nanoparticles

Organic–inorganic hybrid solar cells based on poly(3-hexylthiophene) and electrospun TiO2 nanofibers were fabricated by solution process. The efficiency of the device was improved by modifying CdS nanoparticles on the surface of TiO2 by electrochemical method. The CdS layer can lead to the increase of both open circuit voltage and short circuit current of the device, which are attributed to enhanced exciton dissociation and light absorption and suppressed carrier recombination by CdS at the heterojunction. However, too thick CdS layer led to increased series resistance and decreased efficiency of the device. Therefore, the optimum condition of the CdS deposition was obtained, which increased the power conversion efficiency of the device for about 50%. Our results indicate that the surface modification on the inorganic semiconductor layer is an effect way to improve the performance of the hybrid solar cells.