Synthesis and characterization of polycrystalline CuInS2 thin films for solar cell devices at low temperature processing conditions

Polycrystalline CuInS2 thin films were deposited on glass substrates using a novel solution-based continuous flow microreactor process for the first time. A series of analysis was performed to characterize the CuInS2 thin films using UV–visible spectrophotometer, scanning electron microscope, X-ray diffraction spectrometer, and X-ray photoelectron spectroscopy. The estimated optical band gaps of CuInS2 thin films were in the range of 1.52–1.60 eV. The structural and chemical binding information indicated that CuInS2 thin films with a tetragonal chalcopyrite structure were successfully deposited. Dense film with a thickness around 1 μm could be obtained with a 5 min deposition time. This study demonstrates the solution-based continuous flow microreactor process is a promising low cost alternative for thin film PV manufacturing.