TY  - JOUR
AU  - Gurieva, Galina
AU  - Ernits, Kaia
AU  - Levcenco, Sergiu
AU  - Franz, Alexandra
AU  - Meissner, Dieter
AU  - Schorr, Susan
TI  - Influence of Cu purity and low temperature annealing on Cu/Zn disorder and efficiency of CZTSSe monograins
JO  - Physical review materials
VL  - 9
IS  - 7
SN  - 2475-9953
CY  - College Park, MD
PB  - APS
M1  - PUBDB-2025-04679
SP  - 075403
PY  - 2025
AB  - Thin film solar cell technologies are mainly based on polycrystalline absorber layers, which is also the case for kesterite-based photovoltaic devices. An alternative technology, which is promising and low cost, is based on kesterite-type C⁢u<sub>2</sub>⁢ZnSn⁢(S,Se)<sub>4</sub> (CZTSSe) monograins as absorbers, which are fixed in a polymer matrix to form a flexible solar cell. The large band tailing observed in Cu-based kesterite-type semiconductors is believed to cause voltage losses, limiting the efficiency of kesterite-based devices. Cu/Zn disorder, which is always present in these compounds, is discussed in literature as a possible reason for band tailing. The experimental determination and quantification of Cu/Zn disorder is possible by in-depth analysis of neutron diffraction data. This work reveals that the purity of copper used in the synthesis of CZTSSe monograins has an influence on the degree of Cu/Zn disorder in the semiconductor and thus on optical and PV parameters. Comparing CZTSSe monograins, less Cu/Zn disorder was observed for the monograins synthesized using copper with higher purity; the respective monograin-based solar cell shows a higher power conversion efficiency. On the other hand, the band gap energy as well as the photoluminescence maximum (P⁢L<sub>max</sub>) of both monograins are the same. Applying a low-temperature annealing procedure allowed us to increase the quality of monograins synthesized using 5N copper, very close to the one grown using 6N copper. The P⁢L<sub>max</sub> slightly shifts into higher energy, which is most likely an indication of the decreased Cu/Zn disorder, either moving the defect states toward the valence band or that it reduces the formation of the tail states near the conduction band minimum.
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1103/37sc-4jmy
UR  - https://bib-pubdb1.desy.de/record/639806
ER  -