Chemically Tunable, All‐Inorganic‐Based White‐Light Emitting 0D–1D Heterostructures

Abstract

In this study, one‐dimensional (1D) Mn2+‐doped ZnS (ZnS:Mn) nanowires (NWs) are initially created with a unique optical signature. Specifically, these nanostructures couple (i) ZnS defect‐related self‐activated emission spanning from wavelengths of 400–500 nm with (ii) Mn2+ dopant‐induced emission centered at ≈580 nm. These doped ZnS nanostructures are initially fabricated for the first time via a template‐based coprecipitation approach followed by a postsynthesis annealing process. Novel 1D–0D heterostructures are subsequently formed, incorporating ZnS:Mn2+ NWs and 2‐amino‐ethanethiol (AET)‐CdSe quantum dots (QDs), by assembling annealed ZnS:Mn2+ NWs with AET‐capped CdSe QDs as building blocks via a simple technique, involving physical sonication and stirring. Optical analyses of the heterostructures are consistent with charge (hole) and energy transfer‐induced quenching of ZnS self‐activated emission coupled with hole transfer‐related quenching of Mn2+ emission by the QDs. The CdSe QD emission itself is impacted by competing charge (electron) and energy transfer processes occurring between the underlying ZnS host and the immobilized CdSe QDs. Chromaticity analysis reveals the significance of controlling both QD coverage density and Mn2+ dopant ratios in predictably influencing the observed color of our all‐inorganic heterostructures. For example, white‐light emitting behavior is especially prominent in composites, simultaneously characterized by (i) a 2.22% Mn2+ doping level and (ii) a molar compositional ratio of [ZnS:Mn2+]:[AET‐capped CdSe QDs] of 1:1.5. Moreover, using these independent chemical “knobs,” it is possible to reliably tune for a significant shift within the composites from “cold‐white” (9604 K) to “warm‐white” (4383 K) light emission.

Shedding Light on Host-to-Yb3+ Energy Transfer in Cs2AgBiBr6:Yb3+ (nano)crystals

“…Full decay curves and further details about the fitting procedure and the presence of a fast component can be found in Supporting Information Section S9. Similar to the room temperature decay curves discussed above, the luminescence decay of the undoped NCs is multi-exponential, revealing the presence of multiple decay pathways . In order to determine decay times, a three-exponential fit procedure was used to calculate the weighted average lifetime.…”

“…Similar to the room temperature decay curves discussed above, the luminescence decay of the undoped NCs is multi-exponential, revealing the presence of multiple decay pathways. 46 In order to determine decay times, a three-exponential fit procedure was used to calculate the weighted average lifetime. The resulting average lifetimes are shown in Figure 5 c. To obtain insights into the role of direct ET from the STE to Yb 3+ , the host emission lifetimes of the doped and undoped NCs are compared.…”

Studying Catalytically Viable Single-Crystalline Metal Oxide Nanorods Using Synchrotron-Based Scanning Hard X-ray Microscopy

“…As an illustrative “function” worth exploring, we have been primarily interested in analyzing the electrochemical performance of Ba-based tungstates. In particular, to probe the potential of utilizing tungstates as support materials toward the electro-oxidation of methanol, we have fabricated a series of related samples including (i) Mn-doped BaWO 4 (designated herein as “Mn-BaWO 4 ”) nanorods, (ii) Ba 0.5 Sr 0.5 WO 4 (denoted herein as “BaSrWO 4 ”) nanorods, (iii) pure BaWO 4 controls, and (iv) pure SrWO 4 control samples, using a well-developed, “hard-template”-based method . SHXM, with its high elemental sensitivity and associated capability of achieving deep penetration within the sample itself, was used to map out the elemental distributions of each of these tungstate samples, and these results denoted a set of useful and informative characterization data on these materials, prior to electrochemical testing.…”