Light Emitting Spin Active Electronic States in Ultra-Thin Mn Doped CdSe Layered Nanosheets.

The layered nanosheets exhibit a variety of physical and optical properties originating from amalgamation of intra- and inter- layer electronic interactions, which makes them promising materials for advanced devices with varsatile controlling channels. In particular, the dilute magnetic semiconductor multilayered nanosheets have promising optical, electrical and magnetic properties that have been less explored so far. Here, the spin permissible optical properties from solvothermally grown Mn doped CdSe (thickness ~2.26 nm) multilayered nanosheets are reported on. The presence of multi-phase magnetic orderings with a sharp ferromagnetic transition at temperature ~48 K pertinent to the stabilization and co-existence of Mn2+ and Mn3+ based local phases have been observed from the (Cd,Mn)Se layered nanosheets corroborating to the x-ray absorption near edge structure, electron paramagnetic resonance, Raman scattering and magnetic measurements. The optical absorption and photoluminescence (PL) studies at room temperature affirm wide array of optical properties in the visible regime corresponding to the band edge and intriguing dopant-phase mediated spin approved transitions. The circularly polarized magneto-PL and life time analysis exhibits the spin-polarized fast radiative transitions confirming the presence of spin-active electronic states.

White-light emission by phonon assisted coherent mixing of excitons in Au8-CdS hybrid nanorods.

Gold cluster (Au8) coated CdS hybrid nanorods (HNRs), synthesized using a sonication assisted assembly route, exhibit phonon assisted coherent mixing of excitons. As observed from optical absorption, Raman scattering, x-ray diffraction and transmission electron microscopic studies, the Au8 modulates the crystal-and electronic-structure of the CdS nanorods, effecting enhancement of exciton-phonon (e-p) interactions. The e-p interaction and entropy effect mediated phase matching of the excitonic transitions, leading-via cooperative and coherent mixing of the excitons' color-to the emission of white light, has been confirmed from room temperature and time resolved photoluminescence measurements.