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Most of the ZnS:M (M: transition metal) nanoparticles synthesized from the S2− source in organic and inorganic precursors cause defects, dangling bonds, and vacancies in the surface of nanoparticles, creating nonradiative recombination centres and reducing the photoluminescence (PL) intensity. ZnS:Mn and ZnS:Cu-PVP nanoparticles were synthesized by different methods with sources of S2− in organic and inorganic precursors of Na 2 S, Na 2 S 2 O 3.5H 2 O or HSCH 2 COOH (TGA), and PVP. Then, the surface activation methods used ultraviolet radiation at 325 and 337 nm and visible radiation at 532 nm, 632.8 nm, and 650 nm were used to increase the photoluminescence (PL) intensity of the nanoparticles. The results of the XRD pattern analysis showed that the crystal structure and grain size of the samples did not appear to change due to the radiation annealing process. However, the FT-IR spectra showed that samples using the S2− source from the inorganic precursor Na 2 S, Na 2 S 2 O 3 , exhibited Zn S O 4 formation that was attributed to the photochemical phenomena on the surface of the nanoparticles. The samples using S2− source from organic precursor TGA showed the formation of ZnSO 4 and polyglycolide [CH 2 –COO] n (PGA) polymer on the surface of nanoparticles. This was attributed to the polymerization phenomenon. These photochemical and polymerization processes have the effect of reducing the nonradiative recombination processes of the nanoparticle surface defect states and simultaneously increasing the photoluminescence (PL) intensity of the luminescent centres (Mn2+, Cu2+) from 2.0 to 3.6 times for the ZnS:Mn system and 2.7 times for the ZnS:Cu-PVP system in comparison with the samples that were not annealed. The effects of UV and visible radiation, annealing time, and annealing power on the PL intensity of luminescence centres in the nanoparticles were also investigated and explained. The radiation annealing methods for the samples after synthesis are highly important for improving the optical properties of the nanoparticles and for studies on the fabrication of photovoltaic elements, quantum dots, and LEDs. • The S2− source precursors causing the defect states on surface of ZnS:Mn, ZnS:Cu-PVP. • The luminescence increase of ZnS:Mn, ZnS:Cu-PVP depend on the annealing time, and power of the UV or visible radiation. • For the S2− source using from inorganic precursors: the radiation absorbing surface defect states were modulated into a transparent medium (ZnSO 4) throughout the entire radiation band by photochemical process. • For the S2− source using from organic precursors: Visible radiation can produce photochemical phenomena, while UV radiation can cause both photochemical and polymerization phenomena. • The photon energy of UV radiation has enough large to excite in-situ polymerization reactions to form HOMO, LUMO energy levels of the polymer coating on the surface of the nanoparticles. [ABSTRACT FROM AUTHOR]

Hollow nanosphere H-Gd2O3:Eu3+ was fabricated by multi-step chemical incorporated with hole soft mold using glucose. The H-Gd2O3:Eu3+ monodisperse nanosphere was obtained after thermal treatment at 650 °C. The structural, morphological, and luminescence optical properties of fabricated transparent samples were determined by X-ray diffraction, transmission and field-emission scanning electron microscopies, UV–Visible spectroscopy, Fourier transform infrared spectroscopy, photoluminescence spectroscopy, and Brunauer–Emmett–Teller method. The hollow nanospheres with diameter in the range of 80-100 nm, and the thickness of the shell is about 19 nm tightly packed by nanoparticles. The material is strongly luminescent in the red region, peak emissions correspond to transition characteristics such as 580 (5Do – 7Fo), 592 (5Do – 7F1), 611 (5Do – 7F2), 650 (5Do – 7F3), and 692 nm (5Do – 7F4). The luminescence efficiency was calculated based on the Judd–Ofelt theory, the luminescence efficiency of hollow nanosphere H-Gd2O3:Eu3+ is higher 1.56 than times Gd2O3:Eu3+ 48.45% which leads for many transparent optical devices. [ABSTRACT FROM AUTHOR]