Effects of CBD-derived CdS film thickness on the photovoltaic properties of Cu(In,Ga)Se2 solar cells

This study investigates the effects of the thickness of CdS buffer layers on the photovoltaic properties of Cu(In,Ga)Se2 solar cells. Continuous and dense CdS films were formed with a thickness of 103.7?nm. Increasing the film thickness caused cracks in the prepared films. The illuminated current¡Vvoltage characteristics of the cells revealed that Voc and FF firstly increased and then decreased as CdS film thickness increased over 103.7?nm. The conversion efficiency of Cu(In,Ga)Se2 solar cell increased with the thickness of CdS films. The proper CdS film thickness yielded a maximum conversion efficiency of 11.9?%. Complete coverage of the Cu(In,Ga)Se2 layers by CdS films without cracking reduced the diode factor of the prepared Cu(In,Ga)Se2 solar cells. The UV¡VVis spectra and external quantum efficiency indicated that the absorption loss at short wavelengths decreased as the thickness of CdS films increased. This study found that a CdS film thickness was required to ensure the complete coverage by CdS films to optimize the photovoltaic properties of Cu(In,Ga)Se2 solar cells. ? 2015, Springer Science+Business Media New York.