An InAlN/Mg-doped GaN heterojunction-based self-powered ultraviolet photodetector is demonstrated. Benefiting from the built-in electric field at the heterojunction interface, the device achieves a responsivity of 35.12 mA W-1 and a detectivity of 1.63 & times; 1011 Jones at 340 nm under zero bias, representing more than a fivefold improvement over a conventional metal-semiconductor-metal Mg-doped GaN photodetector. The photodetector also exhibits stable self-powered operation over a wide temperature range from 293 to 398 K, as well as excellent storage stability without encapsulation. These results demonstrate that heterojunction engineering is an effective strategy to unlock the potential of Mg-doped GaN for high-performance and temperature-stable self-powered ultraviolet photodetectors.

At 50 GPa, we conducted a detailed structure prediction and property study on the K-N system in the nitrogen-rich range, and five novel phases are proposed: R3 & oline;m-KN6, Cm-KN7, P6/m-KN8, P1 & oline;-KN9 and P1 & oline;-KN10. The P6/ m-KN8 phase is a sandwich structure: the nitrogen atoms form layer polymeric structure with N18 ring, and the K atom is in the middle of the N ring. The electronic properties indicate that the P6/m-KN8 is a metallic phase, and the further research has confirmed that it is a superconductor: the superconductivity temperature at 50 GPa is 0.283 K. The ELFs show that the hybrid form of N atoms in the P6/m-KN8 phase is sp3. The energy property analysis indicates that energy density of P6/m-KN8 phase is 4.94 kJ/g, which is superior to TNT, the detonation velocity is 18.11 km/s, twice as much as TNT, and the detonation pressure is 202.06 GPa, five times that of TNT.

Self-powered ultraviolet photodetectors are of great interest for next-generation optoelectronic and nanoelectronic applications. In this work, all-inorganic lead-free Cs3Cu2I5 perovskite films were successfully fabricated via vacuum evaporation. Further optimizing the interface state between GaN and Cs3Cu2I5 by introducing a CuI layer. As a result, a Cs3Cu2I5/CuI/GaN heterojunction photodetector was constructed, exhibiting strong ultraviolet sensitivity and a distinct self-powered photoresponse. The device achieves a peak responsivity of 42.9 mA/W at 344 nm, and its performance is enhanced by several orders of magnitude compared with the device without the CuI modification layer. Moreover, the device shows excellent reproducibility and long-term stability, maintaining stable operation after two months without encapsulation. This study demonstrates the potential of Cs3Cu2I5 for short-wavelength optoelectronic devices and provides an efficient and stable architecture for self-powered UV photodetectors. In terms of applications, the device was further applied to UV imaging and enabled clear pattern reconstruction under self-powered operation.

Abstract Under the CONVERGE software platform, different combustion models and soot models were coupled to numerically simulate the turbulent combustion process and soot formation characteristics of n-dodecane. The predicted combustion characteristics and soot formation characteristics were compared and analyzed against experimental values. The results show that the UFPV combustion model provides higher accuracy in predicting the ignition delay and flame lift-off length compared to the WM combustion model. When each of the two combustion models is coupled with the Gokul soot model, the WM combustion model demonstrates higher accuracy in predicting the steady-state soot mass, while the UFPV combustion model exhibits superior accuracy in locating the soot core region and is highly sensitive in capturing the rising process of the soot volume fraction.

To optimize the performance of bidirectional light-emitting diodes (LEDs), this study investigates the effect of different oxygen flow rates on the crystalline phase structure of CuxO thin films. High-quality CuxO films were fabricated via RF magnetron sputtering, achieving a controllable phase transition from Cu2O (111) to CuO (002). Based on this, a bidirectional luminescent LED with a p-CuxO/i-Ga2O3/p-GaN structure was constructed. The device performance and luminescent mechanism were systematically characterized by I-V characteristic measurement, electroluminescence (EL) spectroscopy, and band structure analysis. Results show that the device prepared with optimized oxygen flow rate exhibits excellent rectification characteristics and thermal stability, with a leakage current as low as 2.99 & times; 10-1 0 A at room temperature and 2.62 & times; 10-9 A at 90 degrees C. The device realizes bidirectional luminescence: under forward current driving, it emits 432 nm violet light and 532 nm green light; under reverse current driving, it emits 384 nm violet light and 416 nm blue-violet light. This study clarifies the influence of phase transition regulation on device performance and the bidirectional luminescent mechanism, providing key support for the development of high-performance bidirectional LEDs.

To optimize the performance of bidirectional light-emitting diodes (LEDs), this study investigates the effect of different oxygen flow rates on the crystalline phase structure of CuₓO thin films. High-quality CuₓO films were fabricated via RF magnetron sputtering, achieving a controllable phase transition from Cu₂O (111) to CuO (002). Based on this, a bidirectional luminescent LED with a p-CuxO/i-Ga₂O₃/p-GaN structure was constructed. The device performance and luminescent mechanism were systematically characterized by I-V characteristic measurement, electroluminescence (EL) spectroscopy, and band structure analysis. Results show that the device prepared with optimized oxygen flow rate exhibits excellent rectification characteristics and thermal stability, with a leakage current as low as 2.99×10⁻¹⁰ A at room temperature and 2.62×10⁻⁹ A at 90°C. The device realizes bidirectional luminescence: under forward current driving, it emits 432nm violet light and 532nm green light; under reverse current driving, it emits 384nm violet light and 416nm blue-violet light. This study clarifies the influence of phase transition regulation on device performance and the bidirectional luminescent mechanism, providing key support for the development of high-performance bidirectional LEDs.

Gallium oxide (Ga2O3) films were fabricated by radio frequency magnetron sputtering at different sputtering temperatures, and the physical properties of the films were systematically analyzed. A n-Ga2O3/i-AlN/p-GaN heterojunction light-emitting diode (LED) was manufactured fabricated using optimized process conditions. The device shows good rectification characteristics across various temperatures, with a turn-on voltage of about 2.3 V. Additionally, a systematic investigation of the device's electroluminescence (EL) characteristics revealed that it exhibits typical bidirectional electroluminescence behavior. Under forward bias, the sample emits purple light at 425 nm and blue light at 433 nm. Under reverse bias, the sample emits ultraviolet light at 378 nm and purple light at 422 nm. Then, the change of EL of the device was observed by the temperature control platform. This LED demonstrates a color stability up to 80 degrees C and good temperature stability. Finally, the light-emitting mechanism of the diode was analyzed using band diagrams combined with Gaussian peak fitting of the light-emitting spectrum. This work provides a new approach for the development of special light-emitting semiconductor devices.

Fiber-reinforced aerogels often suffer from fiber aggregation and sedimentation during preparation, leading to structural heterogeneity and degraded mechanical performance. To address this issue, a slight gelation-assisted strategy was proposed to enable the uniform dispersion of polyimide nanofibers (PINFs) within a lightly crosslinked poly(amic acid) salt (PAAS) precursor. The formation of weak gel network increases the system viscosity and provides steric confinement, effectively suppressing nanofiber sedimentation without introducing additional additives. As a result, the obtained aerogels exhibit an ultralow density of 0.0394 g center dot cm- 3, and a high porosity of 97.1%. Furthermore, the aerogels also demonstrate low thermal conductivity (0.03469-0.03675 W center dot m-1 center dot K-1) and excellent acoustic performance, with an average sound absorption coefficient of 0.76-0.84. Nanofiber incorporation increases the internal surface roughness and pore tortuosity, thereby enhancing viscous dissipation of acoustic energy. Meanwhile, the synergistic effect of crosslinked framework and nanofiber reinforcement significantly improves the overall mechanical strength and structural stability. This work provides a simple and scalable strategy for constructing multifunctional polyimide aerogels with integrated thermal insulation and sound absorption capabilities.

This paper takes the applied physics major as an example to explore the systematic application of psychology in the cultivation of basic top-notch talents.By analyzing the psy-chological trait requirements of talents in the applied physics major,it elaborates in detail on the specific application strategies of psychology in the selection of top-notch talents,teaching practice,and scientific research training.Combining the specific teaching cases of the top-notch class in the applied physics major,this study shows that the involvement of psychology has a significant positive effect on the talent cultivation in universities.On this basis,we pro-pose an optimized path for cultivating top-notch talents in the physics major based on subject psychology,providing theoretical references and practical paradigms for the innovative talent cultivation in science and engineering majors.

Flexible perovskite solar cells based on polyimide as the substrate can be used in aerospace vehicles due to their excellent thermal stability and high power-to-weight ratio.However,the metal electrodes of polyimide cause an increase in non-radiative recombination in perovskite solar cells,thereby degrading the performance of perovskite solar cells.In this paper,we propose a method of fabricating flexible perovskite solar cells with polyimide as the substrate based on the ITO modification strategy.By depositing a layer of ITO on the metal electrode,not only is the ratio of Ni3+/Ni2+in the hole transport layer improved,enhancing the conductivity of the hole transport layer,but also the film-forming quality of the perovskite layer is improved,and the non-radiative recombination at the interface between the perovskite film and the hole transport layer(HTL)is suppressed.The flexible perovskite solar cells based on ITO modification strategy have a conversion efficiency of 17.91％.This work provides an effective strategy for fabricating high-efficiency flexible perovskite solar cells.

As a candidate material for next-generation high-performance electronic devices, diamond is constrained by two critical bottlenecks: the low mobility of p-type boron-doped diamond and the formidable challenge of fabricating n-type diamond. Herein, we introduce a novel boron-phosphorus (B-P) co-doping strategy, namely “microwave plasma chemical vapor deposition (MPCVD)-assisted boron pre-doping coupled with 355 nm laser-induced phosphorus doping.” Integrating Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), Raman spectroscopy, Atomic Force Microscopy (AFM), and Hall effect measurements, this study systematically elucidates the regulatory mechanism underlying the strategy. At low laser irradiation times, the samples retain p-type conductivity, with the formation of B-P complexes enhancing hole mobility by 81.86-fold. In contrast, a p-to-n conductivity reversal is realized at high laser irradiation times. This approach successfully yields B-P co-doped n-type diamond, offering a new paradigm for optimizing diamond doping processes while laying a robust technical groundwork for the structural design and performance enhancement of high-performance diamond semiconductor devices.

NiO films were fabricated by radio frequency magnetron sputtering under different oxygen-argon flow ratios (OAFRs) and the correlation between oxygen conditions and film properties was systematically studied. p-NiO films with excellent p-type conductivity (carrier concentration reaching 1.009×1020 cm-3), high crystallinity and low defect density were successfully prepared. A p-NiO/i-AlN/n-GaN heterojunction pure ultraviolet light-emitting diode (UV LED) was fabricated using optimized process conditions. The device exhibited excellent rectification characteristics at different temperatures. The electroluminescence (EL) characteristics of the device indicated that it had excellent pure ultraviolet light emission properties: at different injection currents and different operating temperatures, the device emitted pure ultraviolet light, with the ultraviolet emission accounting for 99%. As the injection current increased, the EL intensity showed power-law growth. Subsequently, the LED emission mechanism and corresponding emission wavelength were analyzed by combining the energy band structure diagram and Gaussian fitting of the EL spectrum. The weak defect-assisted emission at low currents could be suppressed under high currents, and the emission was mainly dominated by the near-band-edge (NBE) intrinsic radiative recombination in GaN. This study provided experimental and theoretical support for the development of high-performance pure ultraviolet LEDs.

Lead-free copper-based halide CsCu2I3 has received extensive attention in the field of ultraviolet (UV) detection in recent years due to its environmental friendliness, easy preparation and photovoltaic stability. However, the strategy to improve the performance of CsCu2I3-based UV photodetectors needs to be fully expanded. In this work, different types of CsCu2I3-based UV photodetectors were constructed by thermal evaporation technology and the responsivity was effectively improved by introducing a CuI buffer layer. The Au/p-CsCu2I3/CuI/n-GaN/In exhibited significant self-powered capability, with the peak responsivity, detectivity, and EQE of 34.06 mA/W, 2.96 & times; 10(10) Jones, and 12.08% (at 350 nm), respectively. Meanwhile, the photodetector exhibits fast response with rise/fall times of 0.79/0.71 ms (at 200 Hz). Even after 1000 on/off cycles and 10 months of storage in air without package, the photodetector can almost maintain the original detectability, showing excellent air stability. The stability of the photodetector is not only shown at room temperature (RT), after operating at 393 K, the photocurrent can also be recovered to similar to 98.53% of the initial value when it is naturally cooled down to RT. What's more, the device also realizes high-resolution UV imaging capabilities. A new strategy for stable, high-performance and nontoxic CsCu2I3-based UV photodetectors is presented in this work.

We have studied the structures and properties of the lithium-nitrogen compounds in the nitrogen-rich region at 100 GPa and 150 GPa using the first-principles calculations. At 100 GPa, three stable structures are discovered and proposed: P1-LiN7, P1-LiN8 and P1-LiN10. At 150 GPa, one stable structure is identified: Pm-LiN8. The properties analysis reveals that these structures show metallic characteristics, and exhibit excellent mechanical properties. The Pm-LiN8 phase remains stable to 750 K at ambient pressure, and the P1-LiN8 phase has a high hardness value (23.42 GPa). These structures possess excellent energy properties, such as the energy density of P1-LiN7 is 5.60 kJ/g, surpassing that of TNT, and its detonation velocity (16.68 Km/s) is more than twice as high as that of TNT, while its detonation pressure (153.15 GPa) is eight times higher than that of TNT.

Carbon dot (CD)-based long-afterglow luminescent materials have attracted widespread attention owing to their unique luminescent properties, eco-friendliness, and extensive application prospects. However, the development of visible light-activated long-lived afterglow based on CD materials remains considerably challenging. Herein, a CD-based composite (Cl-CD@BA) with visible light-activated afterglow was synthesized via thermal treatment of Cl-CD and boric acid (BA). The Cl-CD@BA composite demonstrated room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) dual-mode afterglow emission. Notably, a green TADF emission peak at 525 nm (with 193 ms) could be observed by the naked eye for over 6 s after the composite was excited by white light from a mobile phone flashlight. Furthermore, a concept of information encryption using the Cl-CD@BA composite was proposed through inkjet printing technology, indicating the considerable potential of CD-based afterglow materials in advanced information encryption applications.

Integrating a nitride semiconductor light source on Si is a key to building wide-spectrum photonic systems; however, there have been many challenges in growing nitride semiconductors directly on a Si substrate. Herein, freestanding InGaN/GaN-based microbelts were first prepared by using the electrochemical lift-off (ELO) technique from an as-grown sapphire substrate. The obtained microbelts had uniform morphology and could be flexibly transferred. Subsequently, direct bonding technology was used to transfer and integrate the released InGaN/GaN-based microbelt onto a high conductivity Si substrate to fabricate an on-chip microbelt light-emitting diode (MBLED) with a vertical injection structure. An intermediate amorphous layer with a thickness of similar to 25 nm was formed at the interface of GaN and Si, which was found to have no obvious negative effect on the electrical injection of the MBLED. The prepared Si-based InGaN/GaN MBLED emitted a 465 nm light at the end face of the microbelt with unidirectional luminescent waveguide properties. The luminescence intensity showed a high linear correlation with increasing current. Fowler-Nordheim tunneling (FNT) and thermionic emission (TE) were found to be responsible for its current transport mechanisms at low and high voltages, respectively. This study provides a simple, low-cost method for integrating III-V semiconductor devices on a Si substrate.

GaN-based light-emitting diodes (LEDs) have important applications in medical diagnostics, sterilization, and other fields. However, the mismatch of p-type materials usually makes it difficult for conventional pn-type GaNbased LEDs to obtain pure ultraviolet (UV) emission. In this paper, a series of metal-insulator-semiconductor (MIS)-type diodes with Au/i-AlN/n-GaN structure were prepared by varying the deposition time of AlN films, and the effects of ambient temperature on their electrical and electroluminescence (EL) properties were investigated. The Au/i-AlN/n-GaN diode achieved high-purity UV emission, and the device had the lowest turn-on voltage and the strongest EL intensity when the deposition time of AlN is 40 min. In addition, the effect of ambient temperature on the EL performance of the MIS-type LED was investigated, and the emission was attenuated due to thermal effects at temperatures above 40 degrees C. Finally, we clarified the source of holes from the energy band structure and discussed the luminescence mechanism of the device. The results show that the MIS structure is an attractive choice to effectively realize the UV emission of GaN-based LEDs.

This paper reports a low current driven LED with p-GaN/i-Ga2O3/n-Ga2O3:Si structure prepared by radio frequency (RF) magnetron sputtering, the driving current of the device is only 0.02 mA. Compared with the reported drive current of the LEDs, the reduction is 100 or even 1000 times. Through the study of its electrical properties, it was found that it had excellent rectification characteristics at different ambient temperatures and the turn-on voltage was about 1.8 V. In addition, the leakage current was as low as 4.30 x 10-8 mA. Through the electroluminescence test, it was found that the device had the function of emitting in the ultraviolet (363 nm) and visible (425 nm) region, which realized the blue-violet luminescence at room temperature. Furthermore, the device had excellent high temperature color stability and ultra-low color temperature of 1924 K. The color coordinate of the device at room temperature was (0.1905,0.0955). A detailed study was conducted on the electroluminescence mechanism of the device through its band structure, and the causes of the luminescence were analyzed through the Gaussian fitting of the EL spectrum.

Olefin metathesis is a pivotal method for the synthesis of organic molecules and is widely applied in industrial production. Stereoselective olefin metathesis, as a method for selectively producing E-olefins and Z-olefins, has garnered considerable attention. This review article summarizes the reports on the use of ruthenium catalysts for Z-selective olefin metathesis reactions. Modifications of ruthenium catalyst ligands and control of reaction conditions have been employed to enhance the Z-selectivity in olefin metathesis. Ruthenium complexes containing adamantyl nitrate ligands, monothiol ligands, and dithiol ligands have demonstrated significant effects on the Z-selective metathesis of olefins. This clearly illustrates that ligand modification plays a crucial role in achieving stereospecific olefin metathesis reactions and offers insights for the design of future catalysts.