Improving the Photocurrent in Quantum-Dot-Sensitized Solar Cells by Employing Alloy Pb(x)Cd(1−x)S Quantum Dots as Photosensitizers

Ternary alloy Pb(x)Cd(1−x)S quantum dots (QDs) were explored as photosensitizers for quantum-dot-sensitized solar cells (QDSCs). Alloy Pb(x)Cd(1−x)S QDs (Pb(0.54)Cd(0.46)S, Pb(0.31)Cd(0.69)S, and Pb(0.24)Cd(0.76)S) were found to substantially improve the photocurrent of the solar cells compared to the single CdS or PbS QDs. Moreover, it was found that the photocurrent increases and the photovoltage decreases when the ratio of Pb in Pb(x)Cd(1−x)S is increased. Without surface protecting layer deposition, the highest short-circuit current density reaches 20 mA/cm(2) under simulated AM 1.5 illumination (100 mW/cm(2)). After an additional CdS coating layer was deposited onto the Pb(x)Cd(1−x)S electrode, the photovoltaic performance further improved, with a photocurrent of 22.6 mA/cm(2) and an efficiency of 3.2%.