Browsing by Author "Hu, Fan"

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Improved Efficiency of a Large-Area Cu(In,Ga)Se-2 Solar Cell by a Nontoxic Hydrogen-Assisted Solid Se Vapor Selenization Process
(2014-04-09)
Wu, Tsung-Ta
;
Hu, Fan
;
Huang, Jyun-Hong
;
Chang, Chia-ho
;
Lai, Chih-chung
A nontoxic hydrogen-assisted solid Se vapor selenization process (HASVS) technique to achieve a large-area (40 X 30 cm(2)) Cu(In,Ga)Se-2 (CIGS) solar panel with enhanced efficiencies from 7.1 to 10.8% (12.0% for active area) was demonstrated. The remarkable improvement of efficiency and fill factor comes from improved open circuit voltage (V-oc) and reduced dark current due to (1) decreased interface recombination raised from the formation of a widened buried homojunction with n-type Cd-cu participation and (2) enhanced separation of electron and hole carriers resulting from the accumulation of Na atoms on the surface of the CIGS film. The effects of microstructural, compositional, and electrical characteristics with hydrogen-assisted Se vapor selenization, including interdiffusion of atoms and formation of buried homojunction, were examined in detail. This methodology can be also applied to CIS (CuInSe2) thin film solar cells with enhanced efficiencies from 5.3% to 8.5% (9.4% for active area) and provides a facile approach to improve quality of CIGS and stimulate the nontoxic progress in the large scale CIGS PV industry.
Toward high efficiency and panel size 30 x 40 cm(2) Cu(I,Ga)Se-2 solar cell: Investigation of modified stacking sequences of metallic precursors and pre-annealing process without Se vapor at low temperature
(2014-11-01)
Wu, Tsung-Ta
;
Huang, Jyun-Hong
;
Hu, Fan
;
Chang, Chia-ho
;
Liu, Wen-Long
Modified stacking sequence of precursors and pre-annealing process on Se vapor at low temperature were applied to Cu(ln,Ga)Se-2 (CIGS) solar. The remarkable improvement of efficiency (5.53-10.10% and further 11.04%) and open circuit voltage (0.41 V-0.53 V and further 0.56 V) comes from a compact, smooth microstructure, and modified depth profile of Ga with suitable thickness of CuGa multi-stacking layers in the top of precursors as well as surface bandgap enhancement via pre-nnealing process without Se vapor followed by a specific non-toxic hydrogen-assisted solid Se vapor selenization process. The effects of microstructural, compositional and electrical characteristics of Ga distribution including accumulation and interdiffusion were examined in detail. Finally, a large-area (40 x 30 cm(2)) CIGS solar cell efficiency with improved open circuit voltage (V-OC) and fill factor (FE) of 36% and 14% has been demonstrated, yielding a promising efficiency of similar to 11.04%. (C) 2014 Elsevier Ltd. All rights reserved.