Aqueous synthesis of alloyed CdSexTe1-x colloidal quantum dots and their In-situ assembly within mesoporous TiO2 for solar cells

Ternary alloyed colloidal quantum dots (QDs) have attracted more and more attention due to their distinct optoelectronic properties that may not be present in their parent binary systems, and they have shown great potential application in optoelectronic devices. In this work, ternary alloyed CdSeJei, colloidal QDs were successfully prepared via a simple and facile one-pot hydrothermal technique, and the composition and bandgap of CdSexTe1-x can be tuned by manipulating the feed molar ratio of Se/Te. During the hydrothermal reaction process, the CdSexTe1-x QDs were simultaneously in-situ assembled onto mesoporous TiO2 film due to the use of bifunctional capping agent (thioglycolic acid), so this strategy combines colloidal QDs synthesis and adsorption of QDs within TiO2 in a single step, and thus high loading and uniform distribution of CdSexTe1-x sensitizer within TiO2 matrix could be achieved. The photovoltaic properties of TiO2/CdSexTe1-x photoanode with different composition were investigated, and the best power conversion efficiency of 3.23% under one sun illumination (AM 1.5G, 100 mW cm(-2)) was obtained for the CdSexTe1-x sensitizer synthesized with Se:Te = 2:2. These results show the potential application of hydrothermal method and alloyed CdSexTe1-x QDs in preparing high-performance QDSSC in the future.