Journal Article

PUBDB-2025-04679

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Influence of Cu purity and low temperature annealing on Cu/Zn disorder and efficiency of CZTSSe monograins

Gurieva, G. (Corresponding author)Extern* ; Ernits, K. ; Levcenco, S.Extern*DESY* ; Franz, A. ; Meissner, D.DESY* ; Schorr, S.Extern*

2025
APS College Park, MD

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Please use a persistent id in citations: doi:10.1103/37sc-4jmy  doi:10.3204/PUBDB-2025-04679

Abstract: 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$_2$⁢ZnSn⁢(S,Se)$_4$ (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$_{max}$) 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$_{max}$ 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.

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Contributing Institute(s):

1. PETRA-S (FS-PETRA-S)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. CUSTOM-ART - DISRUPTIVE KESTERITES-BASED THIN FILM TECHNOLOGIES CUSTOMISED FOR CHALLENGING ARCHITECTURAL AND ACTIVE URBAN FURNITURE APPLICATIONS (952982) (952982)

Experiment(s):

1. Measurement at external facility

Appears in the scientific report 2025

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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