We report a simple and yet effective method to introduce Mn(2+) ions into semiconducting nanoclusters with atomically precise control. Our method utilizes one type of micrometer-sized crystals, composed of well-defined isolated supertetrahedral chalcogenide nanoclusters (∼2 nm, [Cd6In28S52(SH)4]) whose core metal site is unoccupied in as-synthesized pristine form. This unique model structure with vacant core site makes it possible to achieve ordered distribution of Mn(2+) dopants, and at the same time effectively preclude the formation of Mn(2+) clusters in the host matrix. A two-step synthesis strategy is applied to realize an atomically precise doping of Mn(2+) ion into the core site of the nanoclusters, and to achieve uniform distribution of Mn(2+) dopants in the crystal lattice. The PL, X-ray photoelectron (XPS), as well as the electron paramagnetic resonance (EPR) spectra reveal the successful incorporation of Mn(2+) ion into the core site of the nanocluster. Different from the pristine host material with weak green emission (∼490 nm), the Mn(2+)-doped material shows a strong red emission (630 nm at room temperature and 654 nm at 30 K), which is significantly red-shifted relative to the orange emission (∼585 nm) observed in traditional Mn(2+)-doped II-VI semiconductors. Various experiments including extensive synthetic variations and PL dynamics have been performed to probe the mechanistic aspects of synthesis process and resultant unusual structural and PL properties. The quaternary semiconductor material reported here extends the emission window of Mn(2+)-doped II-VI semiconductor from yellow-orange to red, opening up new opportunities in applications involving photonic devices and bioimaging.

We apply a two-step strategy to realize ordered distribution of multiple components in one nanocluster (NC) with a crystallographically ordered core/shell structure. A coreless supertetrahedral chalcogenide Cd-In-S cluster is prepared, and then a copper ion is inserted at its void core site through a diffusion process to form a Cu-Cd-In-S quaternary NC. This intriguing molecular cluster with mono-copper core and Cd-In shell exhibits enhanced visible-light-responsive optical and photoelectric properties compared to the parent NC.

We herein present the first case of energy transfer process in an inorganic chalcogenide-based semiconductor zeolite material (coded as RWY) serving as UV−vis light-harvesting host. A multistep vectorial energy transfer assay was fabricated by encapsulating acridine orange (AO) molecules into the RWY porous framework and further covering the formed capsules with rhodamine B (RhB) molecules. The UV high-energy excitations absorbed by RWY host were channeled to AO molecules and then onto RhB molecules to give rise to visible-light emission. The steady-state fluorescence and confocal microscope as well as fluorescent dynamics of emission reveal successfully the process of multistep vectorial energy transfer. This inorganic-host-involved energy transfer process has never been observed in an insulating oxide-based zeolite host system. Therefore, chalcogenide-based semiconductor zeolites could be a class of promising host materials to be further explored in the field of energy transfer and electron transfer between inorganic host and organic guest.

Temperature-sensitive and Mn2+-location-dependent red emission from (Mn/Zn)–Ga–Sn–S supertetrahedral nanoclusters.

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