Title :
High efficiency Cu(In,Ga)Se2-based solar cells: processing of novel absorber structures
Author :
Contreras, Miguel A. ; Tuttle, John ; Gabor, Andrew ; Tennant, Andrew ; Ramanathan, Kannan ; Asher, Sally ; Franz, Amy ; Keane, James ; Wang, L. ; Scofield, John ; Noufi, Rommel
Author_Institution :
Nat. Renewable Energy Lab., Golden, CO, USA
Abstract :
Our effort towards the attainment of high performance devices has yielded several devices with total-area conversion efficiencies above 16%, the highest measuring 16.8% under standard reporting conditions (ASTM E892-87, Global 1000 W/m2). The first attempts to translate this development to larger areas resulted in an efficiency of 12.5% for a 16.8-cm2 monolithically interconnected submodule test structure, and 15.3% for a 4.85-cm2 single cell. Achievement of a 17.2% device efficiency fabricated for operation under concentration (22-sun) is also reported. All high efficiency devices reported here are made from graded bandgap absorbers. Bandgap grading is achieved by compositional Ga/(In+Ga) profiling as a function of depth. The fabrication schemes to achieve the graded absorbers, the window materials and contacting are described
Keywords :
copper compounds; energy gap; indium compounds; semiconductor materials; semiconductor thin films; solar cells; ternary semiconductors; vapour deposited coatings; 12.5 to 17.2 percent; ASTM E892-87; Cu(In,Ga)Se2-based solar cells; Cu(InGa)(SSe)2; absorber structures processing; bandgap grading; compositional Ga/(In+Ga) profiling; contacting; depth function; fabrication; graded bandgap absorbers; high efficiency; high performance devices; monolithically interconnected submodule test structure; standard reporting conditions; window materials; Artificial intelligence; Capacitance-voltage characteristics; Conductivity; Fabrication; Glass; Photonic band gap; Photovoltaic cells; Temperature; Thermal stresses; Zinc oxide;
Conference_Titel :
Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
0-7803-1460-3
DOI :
10.1109/WCPEC.1994.519811
