Title :
Role of i-ZnO in Optimizing Open Circuit Voltage of CIGS2 and CIGS Thin Film Solar Cells
Author :
Jahagirdar, Anant H. ; Kadam, Ankur A. ; Dhere, Neelkanth G.
Author_Institution :
Florida Solar Energy Center, Cocoa, FL
Abstract :
It is a customary in the preparation of CuIn1-xGax Se2 (CIGS) or CuIn1-xGaxS2 (CIGS2) solar cells, to use an un-doped layer of ZnO (i-ZnO) on the CdS layer prior to the deposition of a doped layer (ZnO:AI). This paper presents reasons behind the need for i-ZnO layer and also the effect of its thickness on the open circuit voltage of the CIGS2 based thin film solar cells. It was found that thickness of i-ZnO layer must be optimized depending on the surface roughness of CIGS2 absorber layer. CIGS2/CdS solar cells having optimum i-ZnO thickness were prepared and a photovoltaic conversion efficiency of 11.99% with open circuit voltage, Voc of 830.5 mV under AM 1.5 conditions were obtained. The AM0 efficiency measured at NASA GRC for the same CIGS2 solar cell was 10.25%
Keywords :
II-VI semiconductors; cadmium compounds; copper compounds; indium compounds; semiconductor thin films; solar cells; surface roughness; ternary semiconductors; thin film devices; wide band gap semiconductors; zinc compounds; 830.5 mV; CuIn1-xGaxS2-CdS; CuIn1-xGaxSe2; ZnO; doped layer deposition; open circuit voltage; photovoltaic conversion efficiency; surface roughness; thickness effect; thin film solar cells; NASA; Photovoltaic cells; Photovoltaic systems; Rough surfaces; Solar power generation; Surface roughness; Thick film circuits; Thin film circuits; Voltage; Zinc oxide;
Conference_Titel :
Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
1-4244-0017-1
Electronic_ISBN :
1-4244-0017-1
DOI :
10.1109/WCPEC.2006.279516
