Abstract. The generation of white light from CdS nanoparticles (NPs) illuminated by UV-LED is presented. The synthesis of CdS nanoparticles from the reaction of CdCl2 and the sulfur dissolved in oleylamine in 1:2 mole ratio was used in the preparation of CdS nanocrystalline. The PMMA film doped with CdS nanoparticles was prepared. The generation of white light was found from illumination of the CdS/polymer composite film by UV-LED of power 5 mW at λ = 385 nm. The white light generation mechanism was explaining depending on mixing colors from the illuminated CdS nanoparticles. The surface levels formed in the CdS optical energy band due to nanostructure was estimated from Poisson equation designed for this state. The chromaticity coordinates of the generated white light was measured by the help of photoluminescence (PL) spectrum and the correlated color temperature was found to be about 4000 K.

A hybrid nanoparticles light emitting diode (NPs-LED) was fabricated as layers of ITO/TPD:PMMA/ Eu2O3 / Alq3 / Al, by phase segregation method using spin coating technique. The NPs-LED hybrid device emitted light and consisted of three layers in a definite order placed on the transparent conducting oxide as an ITO substrate; the first layer was made of (N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) benzidine) (TPD) and polymethyl methacrylate (PMMA) polymers combined together. The second layer consisted of Europium (III) oxide (Eu2O3), while the third  layer was Alq3, one of the most frequently-used electron transport layers. The electroluminescence (EL) of NPs-LED was studied with different bias voltages (20, 25 and 30V) at room temperature. Depending on the CIE 1931 color spaces, X the white light was generated at 30V and the green light at 20V. This was achieved by benefitting from the transition between deep levels in the energy gap of Eu2O3 NPs (surface state ) and magnetic dipole transition for Eu+ (5D0-3and5L6 to 7F0-6). The Current – Voltage (I-V) characteristics demonstrated that the current varies with voltage and that the knee voltage value is 5 V. The EL spectrum showed a broad band emission, with a range of 350 - 700 nm. Finally, the correlated color temperature (CCT) was found to be about 7100 to 11500k.

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The synthesis techniques of highly luminescent CdSe/ZnS core-shell composite nanocrystals are reported. The color-conversion, incorporating the photoluminescence emission of CdSe/ZnS core-shell nanocrystals in blue λ=350 nm and green λ=520 nm on near UV-InGaN/GaN LED λ=365 nm, was studied. The generated white light resulting from color-mixing of the emitted wavelengths of  the core-shell composite and that of the near UV emission from the LED was analyzed depending upon the chromaticity coordinates. The X-ray diffraction pattern was used to study the CdSe/ZnS core-shell structure and the nanocrystal size formation. The absorption and photoluminescence spectra of the composite core-shell were investigated. The Gaussian fit was applied to the fluorescence spectrum of the CdSe/ZnS core-shell in order to determine the chromaticity coordinates of the output white light emitted on the chromaticity diagram.

Capacitive–resistive humidity sensors based on polythiophene (P3HT) organic semiconductor as an active material hybrid with three types of metallic nanoparticles (NP) (Ag, Al, and Cu) were synthesized by pulsed laser ablation (PLA). The hybrid P3HT/metallic nanoparticles were deposited on indium-tin-oxide (ITO) substrate at room temperature. The surface morphology of theses samples was studied by using field emission scanning electron micrographs (FE-SEM), which indicated the formation of nanoparticles with grain size of about 50nm. The electrical characteristics of the sensors were examined as a function of the relative humidity levels. The sensors showed an increase in the capacitance with variation in the humidity level.  While the resistivity While the resistivity decrease nonlinearity in the variation of humidity level from 10% to 100%.. The results show that the recovery and response times were higher for the Al/P3HT/Cu/Al sensor compared with those of the other nanoparticles.