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Molten NaF-BeF2salt is widely considered a promising candidate to replace FLiBe in molten salt reactor applications, which is crucial to reducing the operating costs of the molten salt reactor. Studies on beryllium compounds are rarely conducted due to their volatility and high toxicity. Herein, the Be–F coordination structure of NaF/BeF2mixed salts was investigated in-depth through various HT-NMR and solid-state NMR methods, which are optimized to be appropriate for the detection of beryllium compounds. It was found that Na2BeF4and NaBeF3crystals were transformed into amorphous tetrahedral coordinated networks when there was an increase in the BeF2concentration in the mixed salts. The main coordinate structure comparisons between FNaBe and FLiBe were analyzed, which exhibit high similarity due to the covalent effect of Be–F bonding, demonstrating the theoretical feasibility of applying FNaBe salts as a substitute for FLiBe in MSR systems. In addition, the transition from the crystal phase to the amorphous phase occurred at a lower BeF2concentration for FNaBe than that for FLiBe. This was further verified by the results of ab initiomolecular dynamics (AIMD) simulation that FNaBe melts had more disordered structures, thus causing slight changes in their physical properties.

In this study, it was demonstrated that Na+ionic doped crystals could be formed during the solidification of FLiNaK melts. The ionic adulterating behavior between Li+, Na+, and K+ions was investigated in detail by using various 1D/2D solid-state NMR methods and theoretical calculations. 2D 19F–23Na and 19F–7Li HETCOR NMR showed that the Na+ions could be doped into LiF and KF crystals to generate new adulterating phases. Furthermore, the doped ionic Na+ions exhibited different dynamics in LiF and KF crystals, which is correlated to the bonding length of the lattice and the Na–F coordinated interactions. This study provides more insights into the ionic doped crystal phase formation in such simple alkali metal fluorides, which may be of greater significance in the application as optical devices.

Hybridized local and charge-transfer (HLCT) emitters have attracted extensive attention, but the insolubility and severe self-aggregation tendency restrict their applications in solution-processable organic light-emitting diodes (OLEDs), particularly deep-blue OLEDs. Herein, two novel benzoxazole-based solution-processable HLCT emitters (BPCP and BPCPCHY) are designed and synthesized, in which benzoxazole acts as an acceptor, carbazole acts as a donor, and hexahydrophthalimido (HP, with a large intramolecular torsion angle and spatial distortion characteristics) acts as a bulky modified end-group with weak electron-withdrawing effects. Both BPCP and BPCPCHY exhibit HLCT characteristics and emit near ultraviolet in toluene at 404 and 399 nm. Compared to the BPCP, the BPCPCHY solid shows much better thermal stability (Tg, 187 vs110 °C), higher oscillator strengths of the S1-to-S0transition (0.5346 vs0.4809), and faster kr(1.1 × 108vs7.5 × 107s–1) and thus a much higher ΦPLin the neat film. The introduction of HP groups greatly suppresses the intra-/intermolecular charge-transfer effect and self-aggregation trends, and the BPCPCHY neat films placed in air for 3 months can still maintain an excellent amorphous morphology. The solution-processable deep-blue OLEDs utilizing BPCP and BPCPCHY achieved a CIEyof 0.06 with maximum external quantum efficiency (EQEmax) values of 7.19 and 8.53%, respectively, which are among the best results of the solution-processable deep-blue OLEDs based on the “hot exciton” mechanism. All of the above results indicate that benzoxazole is an excellent acceptor for constructing deep-blue HLCT materials, and the strategy of introducing HP as a modified end-group into an HLCT emitter provides a new perspective to develop solution-processable efficient deep-blue OLEDs with high morphological stability.

In this study, quartz thickness-shear mode (TSM) resonator sensors were adopted to monitor the process of platelet activation. Resting platelets adhering to fibrinogen-coated electrodes were activated by different concentrations of thrombin (1, 10, and 100 U/mL), and the corresponding electrical admittance spectra of TSM resonators during this process were recorded. Based on a bilayer-loading transmission line model of TSM resonators, the complex shear modulus (G′ + jG″) and the average thickness (hPL) of the platelet monolayer at a series of time points were obtained. Decrease in thrombin concentration from 100 to 1 U/mL shifted all peaks and plateaus in G′, G″, and hPLto higher time points, which could be attributed to the partial activation of platelets by low concentrations of thrombin. The peak value of hPLwas acquired when platelets presented their typical spherical shape as the first transformation in activation process. The G′ peak appeared 10 ∼ 20 min after hPLpeak, when some filopods were observed along the periphery of platelets but without obvious cell spreading. As platelet spreading began and continued, G′, G″, and hPLdecreased, leading to a steady rise of resonance frequency shift of TSM resonator sensors. The results show high reliability and stability of TSM resonator sensors in monitoring the process of platelet activation, revealing an effective method to measure platelet activities in real-time under multiple experimental conditions. The G′, G″, and hPLvalues could provide useful quantitative measures on platelet structure variations in activation process, indicating potential of TSM resonators in characterization of cells during their transformation.