Park, Sang Yeun Min, Byoung Koun 2025-12-19T06:30:28Z 2025-12-19T06:30:28Z 2025-12-19 2026-04 0256-1115 https://pubs.kist.re.kr/handle/201004/153794 Copper stoichiometry governs the structural, electronic, and photovoltaic properties of Cu(In, Ga)(S, Se)2 absorbers. This review summarizes the effects of the Cu/(In + Ga) ratio on phase stability, defect thermodynamics, and band-edge modulation, and discusses how Cu control contributes to device performance. Under Cu-rich conditions, transient Cu2-x(Se, S) phases enhance grain growth but may cause metallic residues, while Cu-deficient compositions stabilize ordered vacancy compounds that improve p-type conductivity and interface alignment. At the electronic level, reduced Cu content weakens Cu-3d and (S, Se)-p coupling, lowering the valence band and widening the band gap by ~ 0.15–0.23 eV. An empirical Cu-dependent extension of the conventional band gap relation is presented to describe this effect. The optimum Cu/(In + Ga) range (0.85 ~ 0.95) ensures phase stability and minimal defect density, providing a basis for performance enhancement through composition and depth-controlled Cu grading. English 한국화학공학회 Effects of Copper Stoichiometry on Cu(In, Ga)(S, Se)2 Thin-Film Solar Cells Article 10.1007/s11814-025-00612-z 1 Korean Journal of Chemical Engineering, v.43, pp.1157 - 1165 Korean Journal of Chemical Engineering 43 1157 1165 N scie scopus kci 2-s2.0-105023570428 Chemistry, Multidisciplinary Engineering, Chemical Chemistry Engineering Review; Early Access P-N-JUNCTION HIGH-EFFICIENCY CHALCOPYRITE ABSORBER DEPTH LAYER Cu/(In plus Ga) Cu-poor Stoichiometry Solar cells CIGSSe CIGS