title: Tuning Bandgap of p-Type Cu2Zn(Sn, Ge)(S, Se)4Semiconductor Thin Films via Aqueous Polymer-Assisted Deposition.
abstract: Bandgap engineering of kesterite Cu2Zn(Sn, Ge)(S, Se)4with well-controlled stoichiometric composition plays a critical role in sustainable inorganic photovoltaics. Herein, a cost-effective and reproducible aqueous solution-based polymer-assisted deposition approach is developed to grow p-type Cu2Zn(Sn, Ge)(S, Se)4thin films with tunable bandgap. The bandgap of Cu2Zn(Sn, Ge)(S, Se)4thin films can be tuned within the range 1.05-1.95 eV using the aqueous polymer-assisted deposition by accurately controlling the elemental compositions. One of the as-grown Cu2Zn(Sn, Ge)(S, Se)4thin films exhibits a hall coefficient of +137 cm3/C. The resistivity, concentration and carrier mobility of the Cu2ZnSn(S, Se)4thin film are 3.17 ohm·cm, 4.5 × 1016cm-3, and 43 cm2/(V·S) at room temperature, respectively. Moreover, the Cu2ZnSn(S, Se)4thin film when used as an active layer in a solar cell leads to a power conversion efficiency of 3.55%. The facile growth of Cu2Zn(Sn, Ge)(S, Se)4thin films in an aqueous system, instead of organic solvents, provides great promise as an environmental-friendly platform to fabricate a variety of single/multi metal chalcogenides for the thin film industry and solution-processed photovoltaic devices.
authors.affiliation: College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China.
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Yi
authors.affiliation: Department of Electronic and Electrical Engineering, University College London , London WC1E 7JE, United Kingdom.
authors.forename: Jiang
authors.initials: J
authors.lastname: Wu
authors.affiliation: College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.affiliation: College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China.
authors.forename: Jiapeng
authors.initials: J
authors.lastname: Hu
authors.affiliation: College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Dai
authors.affiliation: College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China.
authors.forename: Guifu
authors.identifier: http://orcid.org/0000-0002-8342-7768
authors.initials: G
authors.lastname: Zou
keywords: CZTGeSSe; bandgap tunable; polymer-assisted deposition; solar cells; solution processing