Study On Hybrid Solar Cells Based On One-dimensional TiO₂ Nanorod Arrays

In this paper, vertically aligned one-dimensional TiO2 nanorod arrays were fabricated on the fluorine-doped SnO2 transparent conducting glass oxide(FTO) by a hydrothermal method. The CdSxSe1-x nanoparticles were electrochemical deposited onto the TiO2 nanorod arrays to form the CdSxSe1-x/Ti O2 shell-core nanorod arrays structure. By chemical bath deposition method Sb2S3 nanoparticles were deposited onto the Ti O2 nanorod arrays. Then a conjugated polymer layer of poly(3-hexylthiophene)(P3HT) was spin-coated onto the CdSxSe1-x/TiO2 and Sb2S3/TiO2 nanorod arrays structure to prepare the P3HT/CdSxSe1-x/TiO2 and P3HT/Sb2S3/TiO2 composite films. The morphology, crystal structure, composition and photoelectrochemical properties of the samples were determined and analyzed by means of Scanning electron microscopy, X-ray diffraction, energy dispersive-ray spectroscopy, Ultraviolet-visible diffuse reflection spectrum and photoelectrochemical technique. The main contents are as follows:1) By hydrothermal method, the ordered Ti O2 nanorod arrays were grown on the FTO glass substrates using the mixture of Ti(OBu)4 and HCl solution as the precursor solution. The morphology, crystal structure and photoelectrochemical properties of the nanorod arrays were analyzed.2) By electrochemical method, the suitable thickness of CdSxSe1-x nanoparticles was deposited on TiO2 nanorod arrays to prepare the shell-core CdSxSe1-x/TiO2 nanoarray structure. The CdSxSe1-x/TiO2 nanostructure with different CdSxSe1-x shell thickness was prepared by adjusting the deposition time of the CdSxSe1-x nanoparticle. The energy level of CdSxSe1-x nanoparticles was determined with cyclic voltammetry and UV-Vis absorption spectra. The influence of the CdSxSe1-x deposition time on the morphologies, absorption properties and photoelectrochemical performance of the shell-core CdSxSe1-x/TiO2 nanostructure was investigated.3) The shell-core P3HT/Cd SxSe1-x/TiO2 nanostructures were prepared through a spin-coating method and used as the photoanode to assemble the designed hybrid solar cell. The effect of the CdSxSe1-x shell thickness on the photovoltaic performance of the designed hybrid solar cell was investigated. The working mechanism of the hybrid solar cell was also discussed. As a result, the hybrid solar cell based on the(P3HT)/CdSxSe1-x(9 min)/TiO2 photoelectrode exhibities a short circuit current density(Jsc) of 3.982 mA·cm-2, an open circuit voltage(Voc) of 0.471 V, and a fill factor(FF) of 0.36, resulting in an energy conversion efficiency(η) of 0.68%.4) By the chemical bath deposition(CBD) method, the Sb2S3 nanoparticles were deposited on the surface of Ti O2 nanorod array to form the shell-core Sb2S3/TiO2 nanoarrays structure. Different Sb2S3 nanoparticles shell thickness could be obtained by adjusting the deposition time of the Sb2S3 nanoparticles. The influence of the Sb2S3 deposition time on the morphologies, absorption properties and photoelectrochemical performance of the shell-core Sb2S3 /TiO2 nanostructure was investigated.5) A thin P3 HT layer was spin-coated into the Sb2S3 /TiO2 nanostructure to fabricate the designed P3HT/Sb2S3/Ti O2 composite film. A p-n heterojunction was formed at the interface between n-type Sb2S3 and p-type P3 HT to improve the charge separation and transportation efficiency. The energy conversion efficiency up to 1.15% was obtained with the nanostructure hybrid solar cell based on the P3HT/Sb2S3(3 h)/TiO2 nanoarray.