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Zinc sulfide (ZnS) doped with transition metal has been used as phosphor for various optoelectronic applications. In the present report, ZnS:Mn doped and ZnS:Mn,Ni co‐doped were prepared using chemical co‐precipitation method using polyvinyl pyrolidone as a surfactant. The structural studies were carried out using an X‐ray diffraction technique; optical studies have been performed using ultraviolet–visible light absorption and photoluminescence (PL) spectroscopy. The presences of functional groups were confirmed using Fourier transform infrared spectroscopy. The X‐ray diffraction study and Reitveld analysis confirms the formation of cubic phase with crystalline size 2–3 nm for undoped and doped ZnS nanoparticles. A novel and enhanced luminescence characteristic have been observed in PL spectra. The luminescence intensity of Mn,Ni co‐doped ZnS in the blue region is much higher of that of ZnS. The PL results indicate that the doping of Ni creates shallow trap states or luminescence centres in the forbidden energy gap, which quenches the Mn states emission. Concentration quenching has been observed in Mn‐doped ZnS nanoparticles. From CIE coordinates, it is seen that the yellow and blue light emission of ZnS:Mn,Ni co‐doped nanophosphor may be a promising candidate for display devices and phosphor converted light‐emitting diode applications.

Over the past few decades, many efforts have been put to optimize the properties of electroluminescent devices such as electroluminescence (EL) panel, organic light emitting diode (OLED), flat panel display, EL lamps, etc. In this chapter, the authors provide a comprehensive review of the state-of-the-art research activities related to EL phenomena, the principle of electroluminescence, different types of EL, fabrication of devices, studies on novel electroluminescent materials, their characteristics and potential applications. The authors begin with a historical background of electroluminescence, description of its structure, working principle and parameters with mechanism. They discuss the experiments determining the electrical, optical, and physical properties of the powder as well as thin film EL cells. The recent progress on the improvement of their characteristics and finding novel structures, such as the latest achievements in using various semiconductor nanostructures in polymer matrix as emitting layer in EL devices, are summarized.

Thin films of Sb2S3 and CdI2 composites were deposited by thermal vapor deposition method on a glass substrate. The structural and optical properties have been investigated as a function of the film thickness. Three samples were deposited with thickness of 160[Formula: see text]nm, 210[Formula: see text]nm and 380[Formula: see text]nm. The samples were characterized by X-ray diffraction (XRD), UV–visible (UV–Vis) absorption spectroscopy and photoluminescence (PL) spectroscopy. The XRD result confirms the orthorhombic structure of Sb2S3 peaks. The bigger crystals are formed with the increase of the thickness of the film. The band gaps of the deposited composite thin films were found to be in range 2.17–1.48[Formula: see text]eV and suggest the possibility of band gap tunability in the visible region with the changing the thickness of the film. The PL study reveals the intense emission due to band to band recombination with emission in the red region corresponding to trap states.

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