Title
Stability of CIGS solar cells under illumination with damp heat and dry heat: A comparison
Author
Theelen, M.
Beyeler, K.
Steijvers, H.
Barreau, N.
Publication year
2017
Abstract
Unencapsulated CIGS solar cells were simultaneously exposed to either dry or damp heat combined illumination. In-situ monitoring of their electrical parameters demonstrated a rapid decrease of the efficiency for the solar cells exposed to damp heat plus illumination. This decrease was mainly driven by changes in the shunt resistances, affecting also the open circuit voltage and fill factor, while a minor increase in series resistance was also observed. The solar cells exposed to dry heat plus illumination were almost stable during the exposure. The solar cells were studied before and after exposure in order to investigate their material changes. For the dry heat illumination samples, the visual characteristics remained unchanged, while for the damp heat illumination samples, spots that were likely shunted, were observed. For these solar cells, SIMS showed the migration of sodium, likely leading to changes in the shunt resistance and output voltage. A similar, but less severe migration effect was observed for potassium, so this element might also have a small, but comparable role. Migration of hydroxide, likely caused by water ingression, was also observed and probably affected the conductivity of the ZnO:Al front contact. The migration of sodium and hydroxide was especially strong on the spot locations. These changes were not observed for the dry heat illumination samples. From these experiments, it was concluded that unencapsulated CIGS solar cells can degrade rapidly in the presence of humidity, but in the absence of water, these solar cells were stable even under high temperatures and illumination intensities.
Subject
2015 Nano Technology
TFT - Thin Film Technology
TS - Technical Sciences
Industrial Innovation
CIGS solar cells
Damp heat
Degradation
Dry heat
Humidity
Illumination
Sodium
ZnO:Al
To reference this document use:
http://resolver.tudelft.nl/uuid:81402cb2-4958-492a-95f7-88056e4a1cdb
DOI
https://doi.org/10.1016/j.solmat.2016.12.039
TNO identifier
783528
Publisher
Science Direct
ISSN
0927-0248
Source
Solar Energy Materials & Solar Cells, 166, 262-268
Document type
article