Photosensitization of ZnO rod electrodes with AgInS2 nanoparticles and ZnS-AgInS2 solid solution nanoparticles for solar cell applications

Nanoparticles of a ZnS-AgInS2 solid solution (ZAIS) were successfully immobilized on the surface of ZnO nanorod electrodes without using additional cross-linking agents. Irradiation of ZAIS-immobilized ZnO rod electrodes produced an anodic photocurrent, indicating that ZAIS particles worked as a photosensitizer and that the photogenerated electrons in ZAIS were injected into the conduction band of ZnO nanorods. The magnitude of the photocurrent increased with the red shift of the absorption onset of immobilized ZAIS nanoparticles. Sandwich-type solar cells fabricated with the ZAIS-loaded ZnO nanorod electrode as a working electrode and an acetonitrile solution containing the redox couple of I-/I-3(-) exhibited a photoresponse in the visible light region, being dependent on the chemical composition of the immobilized ZAIS particles. Action spectra of photocurrent agreed well with the diffuse reflectance spectra of the corresponding electrodes. The optimum energy conversion efficiency was 0.72% under irradiation with simulated light of AM 1.5.