Metal chalcogenides such as Cu(In,Ga)(S,Se)₂ (CIGS), CdTe, and Cu₂ZnSnS₄ (CZTS) have empowered significant development in thin-film photovoltaic performance. Nevertheless, the toxicity, scarcity of raw elements in CdTe and CIGS technologies, and unavoidable cationic disorder realized in CZTS hinder the scalability to produce highly efficient solar cells. Here, Cu₂Zn_1–xBa_xSnS₄ (CZBTS) thin films with controllable phase composition and tunable band gap were fabricated on soda-lime glass substrates by a solution-based approach. The impact of replacing zinc with barium with different compositions in CZBTS with x = 0.0–1.0 on structural, morphological, optical, and electrical properties was investigated. It was found that with an increase in x from 0 to 1.0 the band gap energy of CZBTS increased from 1.48 to 1.92 eV with a small bowing constant confirming the significant miscibility of the alloying constituents in the crystal lattice. XRD and Raman studies demonstrate the inclusion of Ba into CZTS thin films and exhibit the structural phase transition from kesterite (tetragonal) to trigonal with increasing Ba content. SEM images reveal compact, homogeneous, and densely packed grain in all the fabricated films. In addition, the Hall measurement for all the materials exhibited p-type conduction behavior and indicates that the hole concentration of CZBTS films varies inversely with Ba content. Our results suggest that the CZBTS alloy is a potentially suitable material as a top cell absorber in a tandem device for efficient solar energy harvesting.

中文翻译：

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钡替代Kesterite Cu ₂ ZnSnS ₄：Cu ₂ Zn _{1– x} Ba _x SnS ₄高效合金收获的五元合金薄膜

金属硫族化物，例如Cu（In，Ga）（S，Se）₂（CIGS），CdTe和Cu ₂ ZnSnS ₄（CZTS），已使薄膜光伏性能得到了重大发展。然而，CdTe和CIGS技术中的毒性，原料的稀缺性以及CZTS中不可避免的阳离子紊乱阻碍了生产高效太阳能电池的可扩展性。在这里，通过溶液法在钠钙玻璃基板上制备了具有可控相组成和可调节带隙的Cu ₂ Zn _{1- x} Ba _x SnS ₄（CZBTS）薄膜。用x代替CZBTS中不同组成的钡钡锌的影响在结构，形态，光学和电学性质上为0.0-1.0。发现随着x的增加从0到1.0，CZBTS的带隙能从1.48 eV增加到1.92 eV，弯曲常数小，这证实了合金成分在晶格中的显着混溶性。XRD和拉曼研究表明，Ba掺入CZTS薄膜中，随着Ba含量的增加，其结构从相变石（四方晶）转变为三角晶。SEM图像显示所有已加工薄膜中的致密，均匀且密实的晶粒。此外，所有材料的霍尔测量均表现出p型导电行为，表明CZBTS膜的空穴浓度与Ba含量成反比。我们的结果表明，CZBTS合金是潜在的合适材料，可以用作串联装置中的顶部电池吸收器，以有效地收集太阳能。