Influence of photo-luminescent CdSe/CdS core shell quantum dots in solar cell efficiency

Abstract

We report the synthesis and characterization of CdSe/CdS core-shell quantum dots (CdSe/CdS-QDs) that exhibit absorption in the UV range of the solar spectrum and emit photons with wavelengths centered around 625 nm, a wavelength that is well suited for silicon absorption and electron-hole pair generation. We also report the fabrication and characterization of single crystal silicon (c-Si) solar cells with and without the aforementioned photo luminescent, down-shifting CdSe/CdS- QDs. The incorporation of these nanostructures triggered improvements in the performance of the devices, particularly in the open circuit voltage (Voc) and short circuit current density (Jsc) for which the measured values showed an increase from 543 to 546 mV and from 32.5 to 37.0 mA/cm2, respectively. The combined effect of the improved values led to an increment in the power conversion efficiency (PCE) from 12.01 to 13.54%. This increase represents a 12.7% improvement in the PCE of the fabricated devices. The effort described herein is considered a good fit to the generalized trend to improve the efficiency of solar cells with mass-compatible techniques that could serve to promote their widespread utilization.