The highly ordered and uniform TiO₂ nanotube arrays were fabricated by anodic oxidation method and PTh(polythiophene)/TiO₂ nanotube arrays electrode were obtained by electrochemical polymerization. X-ray powder diffraction (XRD) analysis confirmed the formation of TiO₂ phase. The morphologies and optical characteristics of the TiO₂ nanotube arrays were studied by scanning electron microscope (SEM), UV-Vis absorption spectra and Raman spectra. The results demonstrate that the PTh/TiO₂ electrode could enlarge the visible light absorption region and increase the photocurrent in visible region. The modified TiO₂ electrode with light-to-electric energy conversion efficiency of 1.46%, the short-circuit current density of 4.52 mAcm^-2, open-circuit voltage of 0.74 V and fill factor of 0.44, were obtained.

Tetrapod-shaped CdSe nanocrystals were obtained using a simple method. HRTEM shows that the average size of the tetrapod core are about 4 nm, widths of the tetrapod arms are about 4 nm and lengths of the arms are about 20 nm. XRD patterns reveal that the OA-capped CdSe tetrapod nanocrystals have a hexagonal wurtzite structure. A hybrid solar cell fabricated based on an 8:1 (w/w) blend of CdSe tetrapod nanocrystals and MEH–PPV showed a maximum power conversion efficiency of 0.46% under an air mass 1.5 global condition. The effects of nanocrystal composition on the photovoltaic properties of hybrid solar cells based on nanotetrapods CdSe/MEH–PPV were investigated. The power conversion efficiency values initially increased and then decreased, but the 𝑉_OC values linearly decreased from 1.1 to 0.25 V with increased CdSe nanotetrapod in the blend film. The significant quenching of PL with increased nanotetrapod concentration indicated photo-induced charge transfer between MEH–PPV and CdSe.