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Transition-metal ions doped nanocrystals (NCs), specifically Mn-doped NCs, hold great potential in the field of photocatalysis, especially, to improve photocatalytic performance for singlet oxygen (1O2) generation. Here, we report the design of a novel Mn-doped NC-based nanocomposites, specifically, silica-coated Mn-doped CdS/ZnS NCs decorated with Pt NCs (denoted as Mn-NCs@SiO2-Pt), which enhance photocatalytic 1O2 generation. Owing to the long-lived Mn excited state (on the order of ms), the energy-transfer between Mn-NCs and molecular oxygen is facilitated with the assistance of the Pt NCs adhered to the Mn-NC@SiO2 surface. Therefore, the Mn-NCs@SiO2-Pt composites, integrate the advantages of Mn-doped NCs, a protective silica layer, and Pt NCs to exhibit excellent catalytic activity and selectivity for the selective oxidation of primary benzylic alcohols to aldehydes through an 1O2 engaged oxidation process under visible-light irradiation. This work paves the way for enhancing catalytic performance via facilitated energy transfer relaxation by utilizing the long-lived excited-state of Mn2+ dopant ions in nanocomposites. [ABSTRACT FROM AUTHOR]

The projection of integrating optical, magnetic and electronic functionalities into a single material have aggravated passionate attention in mounting wide band gap diluted magnetic semiconductor (DMS) in the midst of room temperature ferromagnetism. We report the evidence of ferromagnetism in Cu-doped ZnSe quantum dots (QDs) below room temperature, grown from a single source precursor by lyothermal method with the sizes of approximately 3.2-5.14 nm. QDs mainly exhibit paramagnetic behavior between 80 and 300 K, with a weak ferromagnetic/anti-ferromagnetic exchange at lower temperature as observed by superconducting quantum interference device (SQUID) magnetometer. From the Curie-Weiss behavior of the susceptibility, Curie temperature ( T) of Cu-doped ZnSe sample has been evaluated. From EPR, we obtain the Lande- g factor in the Zeeman interaction term as 2.060. Photoluminescence and EPR measurements support and confirm the view that Cu substitutes for Zn in Cu-doped ZnSe quantum dots. [ABSTRACT FROM AUTHOR]