Publication

Abstract : Tungsten disulphide (WS2) quantum dots, coated on titanium dioxide (TiO2) by chemical bath deposition, increased the photovoltaic performance of dye sensitized solar cells (DSSCs) by ~ 11%. WS2 quantum dots exhibited a dominant optical absorption in a spectral range of 350–800 nm with its characteristics peaks at 550 nm and 620 nm corresponding to the direct bandgap optical transition at the K-point. X-ray photoelectron spectroscopic measurement was performed to study W 4f and S 2p peaks assured the presence of phase-pure WS2 quantum dots. Further, transmission electron microscopic studies showed a distribution of 8.5–20 nm quantum dots with d-spacing of 0.33 nm confirming the WS2. Photovoltaic characteristics of DSSCs with WS2 quantum dots asserted the additional photo-electrons generated by WS2 via the increment in photocurrent density and overall performance. This study demonstrated the possibility of integrating 2D-layered quantum dots into DSSCs as an additional photo-absorbing material candidate along with organic photo-sensitizer such as Ruthenium based N719.