DocumentCode :
3710976
Title :
Bandgap gradients in (Ag,Cu)(In,Ga)Se2 thin film solar cells deposited by three-stage co-evaporation
Author :
Christopher P. Thompson;Lei Chen;William N. Shafarman;Jinwoo Lee;Shannon Fields;Robert W. Birkmire
Author_Institution :
Institute of Energy Conversion, University of Delaware, Newark, 19716, USA
fYear :
2015
fDate :
6/1/2015 12:00:00 AM
Firstpage :
1
Lastpage :
6
Abstract :
(Ag,Cu)(In,Ga)Se2 (ACIGS) solar cells are optimized at bandgaps greater than 1.2 eV by varying composition profile of the absorber layer using a three-stage evaporation process. Numerical modeling and cumulative process data provides insight into the process. Silver alloying CIGS changes the optimized bandgap profile by reducing carrier concentration, and reducing bandgap gradients. The minimum bandgap position is controlled by the point when the film reaches I/III stoichiometry during the second stage of the three-stage process. We achieved a 19.9% efficient solar cell with VOC = 732 mV at a bandgap of 1.2 eV based on quantum efficiency.
Keywords :
"Films","Photonic band gap","Photovoltaic cells","Numerical models","Surface treatment","Process control","Optimization"
Publisher :
ieee
Conference_Titel :
Photovoltaic Specialist Conference (PVSC), 2015 IEEE 42nd
Type :
conf
DOI :
10.1109/PVSC.2015.7355692
Filename :
7355692
Link To Document :
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