Single‐Step Sulfo‐Selenization Method to Synthesize Cu₂ZnSn(S_ySe_1−y)₄ Absorbers from Metallic Stack Precursors

Abstract

Pentenary Cu2ZnSn(S(y)Se(1-y))4 (kesterite) photovoltaic absorbers are synthesized by a one-step annealing process from copper-poor and zinc-rich precursor metallic stacks prepared by direct-current magnetron sputtering deposition. Depending on the chalcogen source--mixtures of sulfur and selenium powders, or selenium disulfide--as well as the annealing temperature and pressure, this simple methodology permits the tuning of the absorber composition from sulfur-rich to selenium-rich in one single annealing process. The impact of the thermal treatment variables on chalcogenide incorporation is investigated. The effect of the S/(S+Se) compositional ratio on the structural and morphological properties of the as-grown films, and the optoelectronic parameters of solar cells fabricated using these absorber films is studied. Using this single-step sulfo-selenization method, pentenary kesterite-based devices with conversion efficiencies up to 4.4 % are obtained.

Electrical properties of sprayed Cu2ZnSnS4 thin films and its relation with secondary phase formation and solar cell performance

“…One of the main challenges for solar cell production based on this absorber material is to obtain single-phase CZTS thin films. On the other hand, regardless of the deposition technique, the highest efficiencies have been obtained in a relatively narrow region of [ [2,3]. The formation of secondary phases is one of the most important mechanisms that can limit the efficiency in thin film solar cells.…”

Effect of post sulfurization temperature on the microstructure of Cu2ZnSn(S,Se)4 thin film

“…There are three routes to obtain mixed sulfoselenide: (1) Selenization of sulfide, e.g. binary or quaternary [4]; (2) Synchronous Sulfo-Selenization of precursor [5]; and (3) Sulfurization of selenide films [6].…”

Fabrication of 5.2% efficient Cu2ZnSn(S,Se)4 solar cells using DC‐sputtered metal precursors followed by sulfo‐selenization

“…Lately, Fairbrother et al synthesized CZTSSe absorber layers by a single annealing process, i.e. sulfo-selenization and a PCE of 4.4 % has been reported [17]. Although they fabricated a good quality TFSCs, the PCE for the devices is still very low and needs to be enhanced.…”