Improved Light Efficiency in Si Solar Cells by Coating Mesoporous TiO2 and Cu‐Modified Mesoporous TiO2

Abstract

In the present work, an improvement in light‐conversion efficiency by coating spherical particles of mesoporous TiO2 (MT) and copper‐modified mesoporous TiO2 (CMT) on single‐crystalline Si solar PV cell is observed. The studies are carried out by spin coating with different concentrations of MT (0.25 to 1.5%) and CMT (0.25 to 1.0%) particles on bare cells independently and compared with a bare solar cell throughout the work. It is observed that in the case of MT coatings, the conversion efficiency increases initially and reaches a maximum of 9.77% at a coating concentration of 1.0%; thereafter, it decreases with an increase in coating concentration. This decrease in efficiency may be attributed to coagulation of MT particles, whereas in the case of CMT particles the conversion efficiency reached a maximum of 8.85% at 0.5% concentration and decreases thereafter. This study indicates that a higher efficiency can be achieved at lower concentrations of CMT coating compared to MT coatings on a bare solar cell. The increase in efficiency may be attributed to better surface passivation and/or trapping of electrons at the metal sites by Cu in CMT. Recombination lifetime measurements results corroborated that CMT particles show better surface passivation as a result of which there is an increase in efficiency. Diffused reflectance and short‐circuit current ratio versus wavelength studies on MT and CMT also revealed that CMT particles perform better than MT particles.