Dual role of Y1.86WO6(Eu0.14)3+ phosphor compound to improve the efficiency of dye-sensitized solar cells

Abstract

Rare earth doped metal tungstate (Y1.86WO6: (Eu0.14)3+) of submicron sized particles were prepared via low-temperature combustion method. This was later used as down converter and light scattering material in dye-sensitized solar cells (DSSCs). Morphological, compositional and optical properties were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), UV-Visible diffuse reflectance spectroscopy (DRS) and Photoluminescence (PL) spectroscopy. These particles were added with other constituents in the process of fabricating N719 or N749 stained photoanode for DSSCs. Devices fabricated using 2 wt% phosphor constituent showed an appreciable enhancement in short-circuit current density (Jsc) as well as higher power conversion efficiency (PCE) compared to devices without phosphor content. The observed enhancement in efficiency is due to downconversion luminescence and light scattering effects arising from these phosphors particles. Further compared with the N719 based device, the enhancement in PCE for N749 based device is 59%. The significant enhancement in PCE is mainly attributed to the optical wavelength matching between the emission of phosphor and the absorbance of the N749 sensitizer. Thus our work demonstrates how the phosphor material dually improves the DSSC efficiencies.