Carbonized polymer dots (CPDs) have received tremendous attention during the last decade due to their excellent fluorescent properties and catalytic performance. Doping CPDs with transition metal atoms accelerates the local electron flow in CPDs and improves the fluorescent properties and catalytic performance of the CPDs. However, the binding sites and the formation mechanisms of the transition‐metal‐atom‐doped CPDs remain inconclusive. In this work, Mn2+‐ion–doped CPDs (Mn‐CPDs) are synthesized by the hydrothermal method. The Mn2+ ions form MnO bonds that bridge the sp2 domains of carbon cores and increases the effective sp2 domains in the Mn‐CPDs, which redshifts the fluorescence emission peak of the Mn‐CPDs slightly. The Mn2+ ions form covalent bonds in the CPDs and remedy the oxygen vacancies of the CPDs, which cuts off the non‐radiative–recombination process of the Mn‐CPDs and increases the quantum yield of the Mn‐CPDs to 70%. Furthermore, the MnO bonds accelerate the electron flow between adjacent sp2 domains and enhances the electron transport in the Mn‐CPDs. Thus, the Mn‐CPDs demonstrate excellent catalytic performance to activate hydrogen peroxide (H2O2) and produce hydroxyl radicals (•OH) to degrade methylene blue (MB) and rhodamine B (RhB).

The development of red emission carbon dots with bright solid-state fluorescence would significantly broaden their application in optoelectronic devices and sensors. Herein, a red-emissive carbon dot-based nanocomposite has been synthesized through chemical bonding with cellulose films. The red emission originating from the surface states of carbon dots was maintained in the cellulose films. Due to the stable chemical bonding, the photoluminescence intensity and emission wavelength remained unchanged for 12 months, and the quantum yield of the composite was enhanced over 4 times. It also showed outstanding stability in water or weak acid–base environments under pHs ranging from 2 to 11. Therefore, the mechanism of chemical bonding that eliminated the defects and preserved the efficient radiative process through surface states was proposed.

Hydrothermal synthesis and up-conversion luminescence ofHo 3+ /Yb 3+ co-doped CaF 2 *Yang Zheng(杨 征) a) , Guo Chong-Feng(郭崇峰) a) † , Chen Ye-Qing(陈叶青) b) , Li Lin(李 琳) a) , Li Ting(李 婷) a) , and Jeong Jung-Hyun(郑仲铉) b) ‡ a)

Metal tungstates, expressed by the general formula of MWO4, have important properties and applications in photoluminescence, microwave applications, optical fibers, scintillator materials, humidity sensors, magnetic properties, and catalysts. In this paper, we report a successful synthesis of CaWO4:Eul+ crystals with various morphologies in mild hydrothermal conditions with surfacntant including sodium citrate, CTAB, PEG and citrate acid (CA). The formation of the crystals are strongly dependent on the employment of surfactant. The surfactant concentration has been found significant influence in the resulting morphologies due to different properties of each one. Extensive characterization have been performed by using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) in search of the formation mechanism of multi-morphological CaWO4:Eu3+ crystals. The growth mechanism of monodispersed CaWO4:EuS+ crystal are proposed. And the photoluminescence properties were investigated.

Bismuth-containing semiconductor material is a hot topic in photocatalysts because of its effective absorption under the visible light. In this paper, we expect to explore a new bismuth-based photocatalyst by studying the subsolidus phase relations of the Bi 2 O 3 -Fe 2 O 3 -La 2 O 3 system. The X-ray diffraction data shows that in this ternary system the ternary compound does not exist, while seven binary compounds (including one solid solution series Bi 1−x La x O 1.5 with 0.167 ≤ x ≤ 0.339) are obtained and eight compatibility triangles are determined.

Cubic-phase CsPbI3 perovskite nanocrystals (CsPbI3 NCs) are widely used as a promising luminescent material in optical devices such as light-emitting diodes and lasers due to their high photoluminescence quantum efficiency and excellent color purities. However, the CsPbI3 lattice is more likely to face the problem of phase transformation due to the poor thermodynamic stability, which would lead to the decrease of its photoluminescence quantum efficiency. In this work, α-CsPbI3 NCs were synthesized by the room-temperature dual-ligand-assisted re-precipitation method under the synergistic effect of n-octanoic acid (OTAC), oleylamine (OLA), and (3-aminopropyl)­triethoxysilane (APTES). The anionic OTAC and cationic OLA ligands interacted with the Pb2+ and I–, respectively, on the surface of the α-CsPbI3 NCs to passivate the defects on the surface. By the adjustment to the volume ratio of the OTAC to OLA, the synergistic effects of the dual ligands inhibited the distortion of the octahedral [PbI6]4– and maintained the cubic perovskite structure of the α-CsPbI3 NCs. The hydrolysis of APTES into the silica layer would provide efficient environmental protection and maintain the cubic phase of α-CsPbI3 at room temperature. The α-CsPbI3 NCs not only produce strong red emission upon the UV excitation but also exhibit strong up-conversion luminescent properties upon the near-infrared excitation at a low excitation power laser of 1064 nm, showing dual-mode luminescent characteristics as a promising material for potential applications in optical devices.

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