TY - JOUR
T1 - Similarities and Critical Differences in Heavy Alkali-Metal Rubidium and Cesium Effects on Chalcopyrite Cu(In,Ga)Se2 Thin-Film Solar Cells
AU - Ishizuka, Shogo
AU - Taguchi, Noboru
AU - Fons, Paul J.
N1 - Funding Information:
We thank H. Higuchi, M. Iioka, and H. Takahashi for their help with the experiments and technical support. We also thank Dr. J. Nishinaga, Dr. H. Shibata, and Prof. N. Terada for fruitful discussion. This work was supported by JSPS KAKENHI grant numbers 16K04969 and 19K05282 and also supported in part by NEDO.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/7/25
Y1 - 2019/7/25
N2 - Both elemental Rb and Cs are known as effective dopants in enhancing Cu(In,Ga)Se2 (CIGS) thin-film photovoltaic device performance. It is, however, found that there are critical differences in the effects of these two alkali metals on CIGS thin-film properties. Namely, CIGS film surfaces show RbInSe2 compound formation after RbF postdeposition treatment (PDT), whereas no such segregated compound formation is observed with CsF-PDT. On the other hand, both Rb and Cs have the effect of increasing effective hole carrier density, photoluminescence intensity, and carrier lifetime in CIGS similar to the effects of the lighter alkali-metals Na and K. The fundamental mechanism behind metastable acceptor formation, which is known as the light-soaking or bias-soaking effect leading to CIGS photovoltaic performance enhancement, is experimentally revealed to be independent of the presence of alkali metals in CIGS, and alkali-metals still have an effect of facilitating metastable acceptor formation.
AB - Both elemental Rb and Cs are known as effective dopants in enhancing Cu(In,Ga)Se2 (CIGS) thin-film photovoltaic device performance. It is, however, found that there are critical differences in the effects of these two alkali metals on CIGS thin-film properties. Namely, CIGS film surfaces show RbInSe2 compound formation after RbF postdeposition treatment (PDT), whereas no such segregated compound formation is observed with CsF-PDT. On the other hand, both Rb and Cs have the effect of increasing effective hole carrier density, photoluminescence intensity, and carrier lifetime in CIGS similar to the effects of the lighter alkali-metals Na and K. The fundamental mechanism behind metastable acceptor formation, which is known as the light-soaking or bias-soaking effect leading to CIGS photovoltaic performance enhancement, is experimentally revealed to be independent of the presence of alkali metals in CIGS, and alkali-metals still have an effect of facilitating metastable acceptor formation.
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U2 - 10.1021/acs.jpcc.9b06042
DO - 10.1021/acs.jpcc.9b06042
M3 - Article
AN - SCOPUS:85070687604
SN - 1932-7447
VL - 123
SP - 17757
EP - 17764
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 29
ER -