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Copper zinc tin sulfide (CZTS) thin films have been deposited by spin coating technique at various copper concentration ranging from 0.5M to 2.5M. The XRD patterns show the existence of the three main characteristic peaks of CZTS (112), (220) and (312), which indicate the formation of the kesterite structure of CZTS. Gap energy was calculated based on the derivation method using the absorbance data, and the values obtained vary from 1.46 eV to 1.58 eV depending on the copper molarities. Hall effect measurements were used to determine the conductivity, which in turn increased with the concentration of copper in the films. The results showed that the C3=1.5M exhibits higher crystallinity and better optical performance among the others. Finally, a theoretical efficiency of 11.6% was obtained by injecting the solar cell (CZTS/ZnS/S:ZnO) in SCAPS1D using the parameters obtained in this study. Under the adopted synthesis conditions, the theoretical simulation corroborated the experimental findings thus confirming that the synthesized material is a promising candidate for solar cell applications as an absorber layer.

Thin Films of Copper Zinc Tin SulfideIn article number http://doi.wiley.com/10.1002/pssa.202100882, Ahmed El Hichou and co‐workers present thin films of copper zinc tin sulfide (CZTS) successfully deposited using the sol–gel spin‐coating technique without any sulfurization. The effect of the solvent type on the structural, morphological, elemental composition, optical, and electrical properties is investigated. All the observed characteristics and results obtained in this study support the usage of spin‐coated CZTS films as absorber layers in thin‐film solar cells.

Nowadays, the compound Cu 2 ZnSnS 4 (CZTS) semiconductor shows great ability to be considered as an alternative of the CIGS thin film in solar cells. Despite the excellent environment stability and the higher power coefficient efficiency which is around 22.6% represented by CIGS [1] and the new updated recorded efficiency (23.4%) according to the NREL site showed by CIGS solar cell, [2] its potentials are limited by scarcity of indium (In) and gallium (Ga), the relatively high cost of In, and also the toxicity issue represented by this element. To solve these issues, it is necessary to search nontoxic and element-abundant light absorber materials. CZTS quaternary semiconductor is constituted by Earth-abundant (Cu:50, Zn:75, Sn:2.2, S:260 ppm) and environmentally benign elements and also the CZTS properties match well with CIGS ones. In fact, the kesterite-based chalcogenide CZTS has a direct bandgap E g ¼ 1.5 eV, which promotes the bandgap of the absorbent layer for high efficiency, an absorption coefficient greater than 10 4 cm À1 , and is characterized by p-type conductivity, which make them ideal among all the secondgeneration thin-film solar cells. [3,4] Moreover, the simulation calculation proves that the CZTS solar cell has theoretical limit power conversion efficiency over 30%. [5,6] Meanwhile, the experimental efficiency of CZTS kept increasing from 6.7% in 2008 [7] to 11.1% in 2012. [8] Wang et al. achieved the highest photovoltaic conversion efficiency of CZTS(Se), which is 12.6%, by exploiting the hydrazine-based approach. [9] In addition to that, reasonable efficiency and great quality were observed for CZTS thin films deposited by many methods, such as sputtering deposition, [10] pulsed laser deposition, [11] and thermal evaporation. [12] However, these techniques require high temperature, high vacuum, and sophisticated tools that may have toxic chemical elements, which have an impact on the fabrication cost of CZTS thin films of a solar cell. To balance the cost and the solar efficiency, several studies tried to elaborate CZTS thin films with low cost and easily synthetic routes. [13][14][15] Among these methods, sol-gel spin coating represents many advantages such as being nonvacuum, facile, low cost, environmentally friendly, and also suitable for large-scale fabrication. It is well known that the properties of thin films prepared with spin coating depend on various parameters. Several articles reported the deposition of CZTS with spin coating and investigated the effect of layer thickness, [15,16] speed of coating, [17] preheating environment, [18] and annealing temperature, [19] on the structural, optical, and electrical properties of CZTS thin films. One of the most important parts of the elaboration of CZTS thin films with spin coating is solution preparation. However, in this step, the type of solvent used has a great impact on the reaction involved, by influencing its nucleation and growth process, which varied the composition and structure of CZTS thin films and controlled the optical and e...