New proposed optical polymeric systems of PVAL/Cu particles have been synthesized by casting proceed to stand their NL (Nonlinear)/L (Linear) optical properties for various optical applications. Herein, the structure of the composites with various wt% of Cu was analyzed by the diffraction of X-ray (XRD) and FTIR. The semi-crystalline nature of PVAL has been influenced by Cu concentration as presented in XRD and Gaussian fitting. FTIR results confirm the strong interaction between Cu and polymer via the main hydroxyl group of the matrix. The morphological surfaces of pristine and doped PVAL have been measured. Optical measurement shows a redshift of the absorption edge. Moreover, the indirect transition bandgap decreased gradually with the Cu-level. This reflects the presence of localized states in the prohibited band facilities the electrons transition from HOMO to LUMO. The extinction coefficient and Urbach energy of the films have been enhanced. The ε o (static) and ε ∞ (high-frequency) dielectric variables are calculated. NL/L refractive index and susceptibility are estimated from the bandgap values. The optical limiting of the composite films has been tested using a green diode laser and He-Ne laser. The PVAL sample with high Cu wt% is an optical system capable of different technical applications, such as solar cells, optoelectronic devices, electronic apparatus, and optical filters.

Owing to its high photosensitivity and excellent optoelectrical properties in the visible range, the TlInSSe single crystal is considered for use in high performance visible photodetectors. Herein, we report a detailed optoelectrical investigation of TlInSSe single crystal grown via the Bridgman technique. The photocurrent was observed to increase with an increase in the illumination intensity. The temperature-dependent photoconductivity under different illumination intensities was studied to understand the photogenerated charge transport mechanism in the TlInSSe crystal. A drop in activation energy was noticed from 0.278 eV (under dark conditions) to 0.114 eV (under illumination), attributed to the filling of trap states by photogenerated carriers. The photo-switching behavior was studied and the growth and decay times were found to be ∼310 and 300 ms, respectively. The photodetector device of the grown crystal was fabricated and the important figure of merit was determined for 532 nm laser light. The photodetector exhibits a responsitivity up to 0.61 A W−1, a detectivity up to 6.24 × 1011 Jones, and an external quantum efficiency up to 120%. These parameters decrease with an increase in the illumination intensity, but increase with applied voltage. These excellent optoelectrical properties make TlInSSe single crystal a highly competitive candidate for visible photodetector devices.

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TlInS 2-layered single crystals were prepared by using a special technique for crystal growth, and the obtained crystals were analyzed by X-ray diffraction. The reflectance and transmittance spectra were measured for the mentioned layered crystals and analyzed over the incident photon energy range 1.96–2.46 eV and in the temperature range 77–300 K. In this work and with the aid of these spectra, the temperature dependence of optical transports and parameters were investigated. In line with the transmittance and reflectance analyses, the refractive index as a function of wavelength was determined in the low-energy region of the studied incident photon energy range. As results of the refractive index–wavelength variations, the oscillator and dispersion energies of the refractive index for the TlInS 2-layered single crystals were determined in the temperature range under investigation. Thereafter, static refractive index and static dielectric constant were also investigated.