title: Influence of Ligands on the Formation of Kesterite Thin Films for Solar Cells: A Comparative Study.
abstract: The preparation of solar-cell-grade Cu2 ZnSnS4 (CZTS) thin films from ligand-capped small-grained CZTS particles remains hindered by problems of phase segregation, composition non-uniformity, and in particular carbon-layer formation. Herein, through a systematic comparative study of annealed films of CZTS nanocrystals prepared using conventional oleylamine and those prepared using formamide, these problems are found to be mainly attributable to the influence of the ligands, and mechanisms are proposed. Importantly, the origin of the carbon layer in oleylamine-capped CZTS films is revealed to be the reaction between oleylamine and sulfur. This carbon layer has a very poor electrical conductivity, which can be the reason for the limited performance of such films. Fortunately, these problems can almost all be avoided by replacing oleylamine with formamide to form CZTS films.
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 117576, Singapore, Singapore.|NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore, Singapore.|Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, 638075, Singapore, Singapore.
authors.forename: Tang Jiao
authors.initials: TJ
authors.lastname: Huang
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 117576, Singapore, Singapore.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Yin
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 117576, Singapore, Singapore.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Tang
authors.affiliation: Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, 638075, Singapore, Singapore.
authors.forename: Guojun
authors.initials: G
authors.lastname: Qi
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 117576, Singapore, Singapore. msegongh@nus.edu.sg.
authors.forename: Hao
authors.initials: H
authors.lastname: Gong
mesh_terms: D000588:Amines / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D011211:Electric Power Supplies; D005559:Formamides / Q000737:chemistry; D008024:Ligands; D053758:Nanoparticles / Q000737:chemistry*; D012993:Solar Energy; D013440:Sulfides / Q000737:chemistry*; D014001:Tin / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D000588:Amines; D005559:Formamides; D008024:Ligands; D013440:Sulfides; D014001:Tin; D003300:Copper; D015032:Zinc; C008703:oleylamine
keywords: copper; ligand effects; thin films; tin; zinc