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Direct evidence for grain boundary passivation in Cu(In,Ga)Se2 solar cells through alkali-fluoride post-deposition treatments.

Authors :
Nicoara, Nicoleta
Manaligod, Roby
Jackson, Philip
Hariskos, Dimitrios
Witte, Wolfram
Sozzi, Giovanna
Menozzi, Roberto
Sadewasser, Sascha
Source :
Nature Communications; 9/4/2019, Vol. 10 Issue 1, pN.PAG-N.PAG, 1p
Publication Year :
2019

Abstract

The properties and performance of polycrystalline materials depend critically on the properties of their grain boundaries. Polycrystalline photovoltaic materials – e.g. hybrid halide perovskites, copper indium gallium diselenide (CIGSe) and cadmium telluride – have already demonstrated high efficiencies and promise cost-effective electricity supply. For CIGSe-based solar cells, an efficiency above 23% has recently been achieved using an alkali-fluoride post-deposition treatment; however, its full impact and functional principle are not yet fully understood. Here, we show direct evidence for the passivation of grain boundaries in CIGSe treated with three different alkali-fluorides through a detailed study of the nanoscale optoelectronic properties. We determine a correlation of the surface potential change at grain boundaries with the open-circuit voltage, which is supported by numerical simulations. Our results suggest that heavier alkali elements might lead to better passivation by reducing the density of charged defects and increasing the formation of secondary phases at grain boundaries. Grain boundaries play critical roles in determining the properties and performance of solar cells based on polycrystalline materials. Here Nicoara et al. showcase that proper treatments passivate defects at grain boundaries by forming secondary material phases with the CIGSe absorbers and lead to higher Voc. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20411723
Volume :
10
Issue :
1
Database :
Complementary Index
Journal :
Nature Communications
Publication Type :
Academic Journal
Accession number :
138430832
Full Text :
https://doi.org/10.1038/s41467-019-11996-y