[en] According to ITER device requirements for cryostat feed through (CFT) technical characteristic and special low temperature and high vacuum environment under feeder systems working condition, taking heat conduction and radiation heat transfer into account, adopting finite elements analysis, feeder systems were engaged in steady state thermal analysis, transient thermal analysis, coupled analysis between structure and heat conduction. The temperature distribution,heat leakage, temperature-time curve and deformation time cure can be obtained, which offer the basis for the design and the improvement of CFT. (authors)

[en] Introducing excess PbI${}_2$ has proven to be an effective in situ passivation strategy for enhancing efficiency of perovskite solar cells (PSCs). Nevertheless, the photoinstability and hysteresis are still tough issues owing to the photolysis nature of PbI${}_2$. Moreover, the humidity-related degradation of perovskite films is also a difficult territory to cover in such an in situ passivation strategy. Herein, a synergistic strategy is reported via initiatively inducing vertical graded PbI${}_2$ distribution (GPD) in the whole perovskite film and capping a cis-Ru(H${}_2$ dcbpy)(dnbpy)(NCS)${}_2$ (Z907) internal encapsulation (IE) layer on the surface to ameliorate the above issues. The GPD design can enhance luminescence, prolong carrier lifetimes, ascertaining the improvement of efficiency and elimination of photoinstability in the PSCs. Besides, the introduced IE layer not only can promote the moisture and thermal resistance, but also inhibit Pb leakage and ion migration in the PSCs. Through the synergetic regulations, the resultant PSCs exhibit an impressive open circuit voltage (V${}_{OC}$) of 1.253 V, fill factor of 81.25%, and power conversion efficiency (PCE) of 24.28%. Moreover, the PSCs maintain 91% of its initial PCE at relative humidity of 85% after 500 h aging and 94% under continuous heating at 85 °C after 750 h aging. (© 2023 Wiley‐VCH GmbH)

[en] In spite of the excellent optical properties of all-inorganic halide perovskite quantum dots (PQDs), they still suffer from inherent poor stability even when exposed to moisture from the atmosphere, restricting their applications, especially in white-light-emitting diodes (LEDs) and cells imaging. Here, we proposed a strategy by encapsulating the CsPbX₃ (X = Cl, Br, I) PQDs into silica nanoplates to prepare highly stable and water-soluble CsPbX₃/SiO₂ nanocomposites. First, the 120 nm monodisperse CsPbX₃/SiO₂ nanocomposites inlayed with several CsPbX₃ PQDs were fabricated via the modified Stöber method. After coating, their stability exposed in the air was largely improved for all the CsPbX₃ (X = Cl, Br, I) PQDs without changing their emission peaks and full-width at half-maximum, attributed to the suppression of the anion-exchange and decomposition. Moreover, further experiments demonstrated that the CsPbX₃/SiO₂ nanocomposites were highly water-soluble and stable in the water. Their applications in LEDs and cell imaging demonstrated their ultrastability and high biocompatibility. Therefore, this study shows the possibility of their use in photoelectric devices and biological applications. (paper)

[en] We consider a quasi-two-dimensional Bose–Einstein condensate with a moving impenetrable disk-shaped potential. By performing direct numerical simulations, we investigate the formation and dynamics of the vortices in the wake as a function of the moving velocity and the radius of the potential. For moderate moving velocity, we observe the formation of a bound vortex pair in the wake of the potential. Its shedding period and associated patterns depend on the radius of the potential, showing V-shaped, periodic, or complex wakes. More interestingly, at high velocity both the vortex pair and vortex dipole can be formed simultaneously. Furthermore, the activation time for vortex formation is investigated for different velocities. We also give an experimental protocol to observe these phenomena in future experiments. (paper)

[en] Carbon dots (CDs) are the promising candidates for application in optoelectronic and biological areas due to their excellent photostability, unique photoluminescence, good biocompatibility, low toxicity and chemical inertness. However, the self-quenching of photoluminescence as they are dried into the solid state dramatically limits their further application. Therefore, realizing efficient photoluminescence and large-scale production of CDs in the solid state is an urgent challenge. Herein, solid-state hybrid nanofibers based on CDs and polyvinylpyrrolidone (PVP) are constructed through an electrospinning process. The resulting solid-state hybrid PVP/CD nanofibers present much enhanced photoluminescence performance compared to the corresponding pristine colloidal CDs due to the decrease in non-radiative recombination of electron–holes. Owing to the suppressed self-quenching of CDs, the photoluminescence quantum yield is considerably improved from 42.9% of pristine CDs to 83.5% of nanofibers under the excitation wavelength of 360 nm. This has great application potential in optical or optoelectronic devices. (paper)

[en] A series of uniform, monodispersed Gd(OH)³:Eu³⁺ nanospheres less than 100 nm were successfully synthesized with iron ions as catalyst and DMF as solvent under the solvothermal condition. Cetyltrimethyl ammonium bromide (CTAB) and Polyvinylpyrrolidone (PVP) were performed as co-surfactant during this facile procedure should be changed as A series of uniform, monodisperse Gd(OH)³:Eu³⁺ nanospheres less than 100 nm in diameter were successfully synthesized with solvothermal method. Iron ion was used as catalyst and Dimethylformamide (DMF) as solvent, Cetyltrimethyl Ammonium Bromide (CTAB) and Polyvinylpyrrolidone (PVP) were performed as surfactants. Further calcination process was applied to prepare Gd₂O₃:Eu³⁺ nanoshpheres during this facile procedure. -- Graphical abstract: Uniform and monodisperse Gd₂O₃:Eu³⁺ and Gd₂O₃:Eu³⁺SiO₂ monodisperse were synthesized by annealed relative parent's Gd(OH)₃:Eu³⁺ and Gd(OH)₃:Eu³⁺SiO₂, respectively. Their morphology and luminescence properties all strongly depended on the iron concentration. Display Omitted

[en] Inorganic perovskite quantum dots (QDs) have attracted wide attention in display and solid-state lighting because of their easily tunable band-gaps and high photoluminescence quantum yields (PLQY) of green light emission. However, some drawbacks limit their practical applications, including the low PLQY of blue light emission and the instability in the moisture environment. In this work, efficient blue-light emitting CsPbBr₃ perovskite QDs with PLQY of 72% were developed through a bandgap engineering approach. The achieved blue-light emitting PLQY is much higher than the values acquired in the inorganic perovskite QDs in the literature. And the emission color of the as-prepared QDs can be facially tuned by only adjusting the reaction temperature. Further, the mono-dispersed perovskite QDs@SiO₂ composites were constructed benefiting from the low temperature synthesis. The optical performance of the QDs could be well persisted even in the moisture environment. Finally, the as-prepared QDs@SiO₂ composite was fabricated as the QD ink on the anti-counterfeit printing technology, from which the obtained pattern would emit varied color under UV lamp. And the as-prepared composites was also applied for fabricating WLED, with Commission Internationale de l’Eclairage (CIE) color coordinates of (0.33, 0.38) and power efficiency of 32.5 lm W⁻¹, demonstrating their promising potentials in solid-state lighting. (paper)

[en] A series of three-dimensional copper oxide (CuO) inverse opals anchored with carboxylated graphene quantum dots (CuO/cGQDs) have been fabricated for non-enzymatic tracking of dopamine (DA). Heterostructures composed of various building blocks are promising to construct versatile biosensing platforms. The optimal CuO/cGQDs modified electrode demonstrates sensitivities of 243.45 μA mM⁻¹ cm⁻² (50 nM–1888.5 μM) with the practical detection limit as low as 0.5 nM in mimic physiological environment (at + 0.45 V vs. Ag/AgCl). The extraordinary tolerance to various interferents enables the practical detection of intracellular DA amount in human neural cells. On this basis, the proposed biosensor attains precise evaluation of antipsychotic drug effects on stimulated DA release. Particularly, it successfully spots fluctuation of DA in plasma and cerebrospinal fluid in murine model of Parkinson’s disease, which serves as a crucial tool to understand neuropathology and symptomatology of DA-related diseases. This study developed a reliable sensing platform and is expected to be applied to physiological and pathological studies. Graphical abstract

[en] Carbon dots (CDs), one of the most significant classes of carbon-based nanophosphors, have attracted extensive attention in recent years. However, few attempts have been reported for realizing CDs with tunable emissions, especially for obtaining the red-light emissions with high photoluminescence quantum yields. Herein, we synthesized CDs with different chromatic blue, green and red emissions by facilely changing the reaction solvent during hydrothermal conditions. The photoluminescence quantum yields of 34%, 19% and 47% for the blue, green and red emissions, respectively, were achieved. Furthermore, the solid-state CD/PVA composite films were constructed through mixing the CDs with PVA polymer, in which the self-quenching of photoluminescence of CDs had been successfully avoided benefiting from the formation of hydrogen bonds between the CDs and PVA molecules. Finally, the warm white light emitting diode (WLED) was fabricated by integrating CD/PVA film on a UV-LED chip. The WLED exhibited the Commission International de l’Eclairage coordinates (CIE) of (0.38, 0.34), correlated color temperature of 3913 K and color rendering index of 91, respectively, which were comparable with the commercial WLEDs. (paper)

[en] Carbon dots (CDs) have emerged as a new type of fluorescent material because of their unique optical advantages, such as high photoluminescence quantum yields (QYs), excellent photo-stability, excitation-dependent emissions, and low toxicity. However, the photoluminescence mechanism for CDs remains unclear, which limits their further practical application. Here, CDs were synthesized via a solvothermal route from citric acid and urea. Through the oxidation and reduction treatment of pristine CDs, the origin of the photoluminescence and the involved mechanism were revealed. We found that the blue/green/red emissions originated from three diverse emitting states, i.e. the intrinsic state, and C=O- and C=N-related surface states, respectively. Based on the as-prepared CDs, a pH sensor depending on the radiometric luminescence detection was developed. Furthermore, we constructed CD/PVP (PVP, polyvinylpyrrolidone) composite films, which exhibited white light emission with photoluminescence QYs of 15.3%. The white light emission with different correlated color temperatures (CCTs), from 4807 K to 3319 K, was obtained by simply changing the amount of PVP solution. Benefiting from the white light-emitting solid-state films, single-component white light-emitting diodes were fabricated with an average color rendering index value (Ra) of 80.0, luminous efficiency of 10.2 lm W⁻¹, and good working stability, thus indicating a promising potential for practical lighting applications. (paper)