Enhanced photoelectric performance of CdS/CdSe co-sensitized TiO2 nanosheets array films

Abstract

In this study, vertically aligned titanium dioxide nanosheets (TiO₂NSs) array films were employed for the fabrication of photoanodes for quantum-dot sensitized solar cells (QDSSCs). The TiO₂NSs array films were synthesized by a hydrothermal method. Then, cadmium sulfide (CdS) and cadmium selenide (CdSe) were assembled onto the TiO₂NSs array films through chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR), respectively. Detailed characterization measurements were carried out to analyse the crystallinity, microstructure, composition and optical properties of the samples. The CdS and CdSe QDs were densely and uniformly deposited on both {001} and {101} facets of the TiO₂NSs array films. Moreover, the effect of CdS deposition time and number of CdSe deposition cycles (C) on the photoelectric performance was also investigated in detail. The best performance of 4.77% was achieved under AM 1.5 G illumination with J_sc = 18.22 mA cm⁻², V_oc = 0.51 V, and FF = 0.52 when the deposition time of CdS was 30 min and the deposition cycle of CdSe was 10C. The enhanced photoelectric performance mechanism of the co-sensitized device is also discussed in this paper.