Terahertz-based optoelectronic properties of ZnS quantum dot-polymer composites: For device applications

[Display omitted] •THz based optical characterization of ZnS QD of different concentrations.•Fluorescence and Decay Life time measurement of Zinc Sulfide QDs.•Measurement of Kirchhoff surface scattering Property of ZnS QD in THz domain.•Optical impedance, surface roughness, and reflection coefficients of ZnS QDs in TE and TM mode in THz frequency range.•Evaluation of ZnS QDs for the development of low-cost CMOS camera in THz domain. Terahertz (THz) technology integration with nanomaterials is receiving excellent attention for next-generation applications, including enhanced imaging and communication. The excellent optical properties in THz domain can lead to preparation of low-cost CMOS camera which can convert THz radiation into optical signal in very efficient manner. In the present study, we have studied the properties of Zinc Sulfide quantum dots (ZnS QDs) embedded with Polyvinyl Alcohol (PVA) composites films using THz Signal at room temperature. The optical characterizations such as refractive index, absorption coefficients and dielectric constants of these samples were measured in the 0.1–2.0 THz range. Additionally, optical impedance, surface roughness, and reflection coefficient in TE and TM mode between 0.1 and 2.0 THz range were determined for these samples based on surface roughness-based reflection and scattering properties. The surface roughness factor was used to measure the optical impedance of the ZnS QDs based polymer films. The measured values of the absorption coefficient at 266 nm are compared with THz radiation, and the refractive indices of these samples range from 1.75 to 2.0. Finally, these samples were subjected to UV light excitation (λexe = 266 nm) of 0.15 ns duration and 400 nm for the fluorescence and corresponding life time measurements. We observed two numbers of fluorescence lines in nanosecond based excited domain whereas 400 nm excitation-based fluorescence life time lies between 13.8–11.39 ns range along with shift in fluorescence lines between 538.7 to 560.7 nm, respectively.