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Impact of air‐light exposure on the electrical properties of Cu(In,Ga)Se 2 solar cells
Author(s) -
Hölscher Torsten,
Schneider Thomas,
Maiberg Matthias,
Scheer Roland
Publication year - 2018
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.3041
Subject(s) - open circuit voltage , solar cell , materials science , optoelectronics , annealing (glass) , open air , short circuit , spectroscopy , air mass (solar energy) , voltage , composite material , physics , boundary layer , quantum mechanics , engineering , thermodynamics , architectural engineering
The impact of air‐light exposure of bare Cu(In,Ga)Se 2 layers is investigated by measuring the performance of completed solar cells. Solar cells formed from air‐light–exposed absorbers reveal inferior cell parameters by about 10% regarding open circuit voltage, fill factor, and efficiency compared with cells from nonilluminated absorbers. Time‐dependent and temperature‐dependent open circuit voltage measurements give reasons that the solar cell impairment by air‐light exposure of the bare absorbers is due to interface recombination. Interface states are detected by admittance spectroscopy. Heat‐light soaking of complete solar cells—having formerly degraded interfaces—recovers the solar cell parameters up to the nondegraded levels. Paradoxically, both the air‐light–induced degradation of bare absorbers and the revision of cell parameters after light annealing go along with a light‐induced segregation of sodium at the Cu(In,Ga)Se 2 surface and Cu(In,Ga)Se 2 /CdS interface, respectively.