Abstract Lamellar transition metal dichalcogenides have become a burning research topic over the past few decades owing to their exotic chemical and physical properties. To exploit their potential in the majority of electronic and optoelectronic devices, researchers are grappling with the challenge of synthesizing high-purity materials with preferred crystal orientation and chemical composition. In this work, tungsten diselenide (WSe2) single crystals were synthesized via chemical vapour transport (CVT) technique. Morphological, optical and structural characteristics of prepared WSe2 crystals were analysed with UV-visible spectroscopy, X-ray diffraction (XRD), Raman and high-resolution transmission electron microscopy (HRTEM), which reflect the formation of high purity WSe2 single crystal. Further, the application of this material is tested as a buffer layer with back contact in CdS/CdTe solar cells. The optimized buffer-layer thickness produced a good efficiency of 6.82%. The findings of this study provide a potential route to synthesize high-purity WSe2 single crystals for application in all-important CdTe thin-film solar cells.
Afzal et al. (Wed,) studied this question.