Synthesis of uniform and dense metal nanostructures on the whole exposed fiber, instead of simply on the membrane surface, is necessary for controllable separation and sensitive SERS detection. Herein, uniform and dense AuNP/MoS₂ hybrids were synthesized on single 3D glass fiber (GF) surfaces, obtained by the reaction of a MoS₂ nanosheet and HAuCl₄. The chemical mechanism (CM) of the MoS₂ layers and the electromagnetic enhancement (EM) of the dense AuNPs were used to enhance the SERS sensitivity. The molecule-separation ability of the obtained GF membranes, constructed by numerous compacted fibers with dense AuNP/MoS₂ hybrids, was not destroyed, and herein, these membranes were used to separate mixed molecules. These MoS₂-based hybrid substrates show great potential for excellent paper-based separation and are sensitive SERS substrates for biological and chemical detection.

Organic room temperature phosphorescence (RTP) has been widely investigated to realize long-lifetime luminescent materials and improvement in their efficiency is a key focus of research, especially for red and near-infrared (NIR) RTP molecules.

First-principles investigation on relationships between structures and luminescent properties for TSCT-based TADF molecules.

Red and near-infrared (NIR) thermally activated delayed fluorescence (TADF) molecules show excellent potential applications in organic light-emitting diodes (OLEDs). Due to the lack of systematic studies on the relationship between molecular structures and luminescence properties, both the species and amounts of red and NIR TADF molecules are far from meeting the requirements for practical applications. Herein, four new efficient molecules (DQCN-2spAs, TPCN-2spAs, DPCN-2spAs and BPCN-2spAs) are proposed and their photophysical properties are theoretically predicted based on first-principles calculations and thermal vibration correlation function (TVCF) theory. The results show that all molecules exhibit red or NIR emissions and they have fast radiative decay rates and reverse intersystem crossing (RISC) rates, and the excellent TADF luminescence properties are predicted. Moreover, based on spiro-acridine (spAs) as the donor unit, the combination with different acceptors can change the dihedral angle between the ground state and the excited state, the bending degree of the donor is positively correlated with the reorganization energy, and this feature can have a great influence on the non-radiative process. Furthermore, based on these theoretical predictions, experimental verifications are performed and the synthesized BPCN-2spAs is confirmed to be an efficient NIR TADF molecule. Thus, the relationships between basic molecular structures and photophysical properties are revealed, a feasible design strategy is applied and four promising red and NIR TADF molecules are proposed. All these results could contribute to the development of red and NIR TADF emitters and OLEDs.

Raspberry-like bimetal Au@AgNPs nanostructures with multiple hotspots on an arrow-shaped paper strip to sensitively detect the complex samples.

Improving the internal quantum efficiency and optimizing the horizontal dipole orientation in near-infrared thermally activated delayed fluorescence (TADF) molecules are highly desired outcomes. Herein, the excited-state properties of three reported TADF molecules (DPDBP-TPA, 2CNDPDBP-TPA and 4CNDPDBP-TPA) are theoretically investigated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations coupled with the thermal vibration correlation function (TVCF) method. The results demonstrate that the introduction of cyano groups enhances the charge transfer features of the molecules, leading to small energy gaps (ΔE_ST). Additionally, this adjustment effectively optimizes the energy levels and transition characteristics of the excited states, and also significantly accelerates the reverse intersystem crossing (RISC) process. Based on this point, five new near-infrared TADF molecules are theoretically designed using a donor engineering strategy. Their crystal structures are predicted with a lower energy and higher packing density, and the photophysical properties of the designed molecules both in toluene and solid phase are studied in detail. The designed molecules not only possess increased molecular lengths but also ensure quasi-planar conformations. Moreover, intramolecular hydrogen bonds enhance the rigidity of the molecules. Collectively, these factors assist in enhancing the horizontal dipole orientation. Notably, the significantly reduced ΔE_ST in the solid phase lead to rapid RISC processes and enhance TADF properties. Thus, five new near-infrared TADF molecules are verified and inner relationships between molecular structures and photophysical properties are detected, which could pave the way for the development of novel efficient near-infrared TADF molecules.