ABSTRACT
Fluorescent carbon dots (CDs) are a new type of photoluminescent nanomaterial. Solid-state CDs usually undergo fluorescence quenching due to direct π-π* interactions and superabundant energy resonance transfer. Therefore, the preparation of solid-state fluorescent CDs is a challenge, especially the preparation of long wavelength solid-state CDs. In this research, long wavelength emission CDs were successfully synthesized by solvothermal methods, and the prepared CDs showed good hydrophobicity. The composite solid-state CDs/PVP (Polyvinyl pyrrolidone) can emit strong red fluorescence, and the quantum yield (QY) of the CDs/PVP powder reaches 18.9%. The prepared CDs/PVP solid-state powder was successfully applied to latent fingerprint detection. The results indicate that the latent fingerprints developed by CDs/PVP powder have a fine definition and high contrast visualization effect, which proves that the prepared CDs/PVP has great application potential in latent fingerprint detection. This study may provide inspiration and ideas for the design of new hydrophobic CDs.
ABSTRACT
We report a multi-resonant thermally activated delayed fluorescent (MRTADF) afterglow emitter with unprecedented long emission lifetime > 100 ms, full-width at half-maximum < 40 nm, and deep-blue emission color of CIEy at 0.048. Such emitters remain rarely achieved and would show potential applications in multiplexed bioimaging and high-density information encryption.
ABSTRACT
Equity in the inheritance culture of family property is an important component of humanistic health in modern living environments. The inheritance of property under Chinese traditional family culture is the material basis for the continuation of family and clan. This study demonstrates the equity component embedded in traditional family inheritance culture and further studies of the healthy human settlements environment. Based on the theory of "equal share for all sons" in ancient China and the "equity" and "justice" that are of modern significance, this paper analyzes the family division culture of individual traditional housing and the corresponding impact indices of family division equity. Taking Renhe Village, a typical local residential building of the middle and late Qing Dynasty as the research object, this study built a spatial syntax data model and 3D simulation technology for the simulation analysis of space and climate. The results show that Renhe Village meets the requirements of the equity evaluation system of housing property rights distribution in terms of the natural unit indicator (quantity, lighting, ventilation) and the overall spatial indicator (privacy, centrality, convenience). In other words, equity does not mean an absolute average share, but an equity culture formed after six evaluation indices under the subdivision of two indicators are balanced. Based on the above, an equity system model of housing property rights distribution was established, and the weight of the ancients' attention to the housing distribution standard was explored. It is further found that the ancients attached more importance to light among the natural unit indicators, and attached the most importance to centrality in the overall spatial indicators. These findings provide new ideas for understanding the equity of property inheritance under Chinese traditional family culture. They also provide quantifiable criteria for the distribution of modern rural housing and social security housing, and ultimately provide a reference for the humanistic public health of the modern living environment.
Subject(s)
Environment , Housing , Humans , China , Public HealthABSTRACT
It remains challenging to fabricate highly-efficient and long-lived organic afterglow materials, especially in the case of red afterglow systems. Here we develop advanced charge transfer (CT) technology to boost afterglow efficiency and lifetimes in fluoranthene-containing dopant-matrix systems. First, organic CT molecules possess singlet-triplet splitting energy (ΔEST ) of around 0.5â eV, much smaller than localized excitation systems. Second, upon doping into suitable organic matrices, dipole-dipole interactions between 1 CT states and organic matrices reduce 1 CT levels with less effect on 3 CT levels, and thus further narrow ΔEST and enhance intersystem crossing. Third, the rigid planar structure of fluoranthene groups and the rigid microenvironment provided by organic matrices can suppress phosphorescence quenching. Forth, the multiple donor design enables spectral red-shifts to red region and switches on TADF mechanism to improve afterglow efficiency to 13.1 % and maintain afterglow lifetime of 0.1â s. Such high-performance afterglow materials have been rarely explored in reported studies.
