Efficiency Enhancement of Cu(In,Ga)Se2 Solar Cells by Applying SiO2-PEG/PVP Antireflection Coatings

An effective approach was presented to enhance photoelectric conversion efficiency of Cu(In,Ga)Se2 (CIGS) solar cells by using modified SiO2 antireflection coatings (ARCs) to harvest more incident sunlight. Polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) used as additives were introduced into silica sols to prepare SiO2-PEG and SiO2-PVP coatings in the sol-gel dip-coating process, respectively. The different effects of PEG and PVP additives on SiO2 coatings were analyzed and the antireflection performance of SiO2-PEG and SiO2-PVP coatings was investigated. The transmittance over 97% ranging from 450 nm to 700 nm with a maximum transmittance over 99.40% at about 550 nm was achieved for both SiO2-PEG2000A and SiO2-PVP0.5 coatings. The relative efficiencies of CIGS solar cells coated with SiO2-PEG2000A and SiO2-PVP0.5 ARCs were increased by 7.27% and 8.33%, respectively. The modified SiO2 ARCs possessed the advantages of the low manufacturing cost, good adhesion, superior antireflective performance and the feasible method for large area fabrication.