Highly efficient CdTe/CdS quantum dot sensitized solar cells fabricated by a one-step linker assisted chemical bath deposition

Abstract

We report on an interesting and efficient one-step linker assisted chemical bath deposition method to synthesise CdTe or CdTe/CdS quantum dot sensitized TiO₂ photoelectrodes. The CdTe or CdTe/CdS core/shell quantum dots with different size and structure can be easily obtained by controlling the hydrothermal temperature. The QDs are covalently linked to TiO₂ nanocrystallites by thioglycolic acid (TGA) bifunctional molecule which also acts as stabilizer and sulfur source in this one-step fabrication. In this sensitized electrode, CdTe has higher light absorptivity while the CdS shell plays a crucial role in the sensitive CdTe QDs protection and photo-generated charges separation. Both effects push the power conversion efficiency of the quantum dot sensitized solar cells (QDSSCs) up to 3.8% and 5.25% under AM 1.5 G one sun (100 mW cm⁻²) and 0.12 sun illumination, respectively.