Jicai Zhang

Te co-sputtering optimizes SnTe films' defect chemistry and microstructure, yielding fine grains with enhanced carrier concentration via Te _Sn antisites, achieving power factor of 141 µW cm ^-1 K ^-2 and device output of 44.75 nW at Δ T = 60 K.

Boron nitride films are deposited on sapphire substrates with miscut angles (C-plane toward M-direction, 0.1°–4.0°) using radio frequency magnetron sputtering. The deposited films exhibit the characteristic hexagonal boron nitride (h-BN) phase with smooth, dense, and continuous surface morphology. Increasing the substrate miscut angle leads to a progressive deviation of the absorption edge and optical bandgap from those of ideal single-crystalline h-BN. Raman spectroscopy reveals a redshift and broadening of the E2g vibrational mode with increasing miscut, indicating reduced crystallinity and enhanced internal stress. The h-BN film grown on the substrate with a miscut angle of 0.1° shows the most desirable characteristics, including a bandgap of 5.59 eV, minimal residual stress, and the narrowest E2g peak. Metal–semiconductor–metal photodetectors fabricated from the optimized h-BN film demonstrates excellent performance, achieving a photo-to-dark ratio of 217 and a responsivity of 8240 μA/W at 20 V bias. These findings elucidate the influence of substrate miscut on the structural and functional properties of sputtered h-BN films, offering guidance for the controlled growth of high-performance BN-based optoelectronic devices.

Single-crystal semipolar (11-22) AlN templates are grown on 2 in. m-plane sapphire substrates via high-temperature hydride vapor phase epitaxy. Pulsed HCl and NH3 precursors are used separately to enhance Al mobility and reduce parasitic reactions, thereby improving the crystal quality of an AlN film. Compared with continuous growth, the FWHM (full width at half maximum) of the x-ray rocking curves of a (11-22) AlN film grown with pulsed HCl decreased from 882″ to 616″ along [11-23]AlN and from 684″ to 608″ along [1-100]AlN, indicating a significant reduction in the defect density of the AlN film. This improvement in crystal quality benefits from the prolonged Al mobility, which facilitates the transition of an AlN growth mode from 3D (three-dimensional) islands to a 2D (two-dimensional) step flow. However, the crystal quality of the film grown with NH3 pulses deteriorates, which may be due to the formation of subgrains with different crystal orientations caused by the long interruption of NH3. Based on the optimized growth conditions, a 7 μm-thick single-crystal (11-22) AlN film is prepared using HCl pulses, exhibiting smooth surface morphology with typical macrosteps, providing a substrate foundation for subsequent homoepitaxial AlGaN-based deep ultraviolet optoelectronic devices.

Triboelectric nanogenerators (TENGs) have attracted widespread attention as a promising candidate for energy harvesting due to their flexibility and high power density. To meet diverse application scenarios, a highly stretchable (349%), conductive (1.87 S m^-1), and antibacterial electrode composed of carbon quantum dots/LiCl/agar-polyacrylamide (CQDs/LiCl/agar-PAAm) dual-network (DN) hydrogel is developed for wearable TENGs. Notably, the concentration of agar alters the pore spacing and pore size of the DN hydrogel, thereby impacting the network cross-linking density and the migration of conductive ions (Li⁺ and Cl^-). This variation further affects the mechanical strength and conductivity of the hydrogel electrode, thus modulating the mechanical stability and electrical output performance of the TENGs. With the optimal agar content, the tensile strength and conductivity of the hydrogel electrode increase by 211 and 719%, respectively. This enhancement ensures the stable output of TENGs during continuous operation (6000 cycles), with open-circuit voltage, short-circuit current, and transferred charge increasing by 200, 530, and 155%, respectively. Additionally, doping with CQDs enables the hydrogel electrode to effectively inhibit the Gram-negative bacterium Escherichia coli. Finally, the TENGs are utilized as a self-power smart ring for efficient and concise information transmission via Morse code. Consequently, this study introduces a creative approach for designing and implementing multifunctional, flexible wearable devices.

Single-crystal semi-polar (112̄2) AlN films are grown on 2-inch m -plane sapphire substrates by high-temperature hydride vapor phase epitaxy (HVPE).

Ultraviolet (UV) radiation has been widely utilized as a disinfection strategy to effectively eliminate various pathogens. The disinfection task achieves complete coverage of object surfaces by planning the motion trajectory of autonomous mobile robots and the UVC irradiation strategy. This introduces an additional layer of complexity to path planning, as every point on the surface of the object must receive a certain dose of irradiation. Nevertheless, the considerable dosage required for virus inactivation often leads to substantial energy consumption and dose redundancy in disinfection tasks, presenting challenges for the implementation of robots in large-scale environments. Optimizing energy consumption of light sources has become a primary concern in disinfection planning, particularly in large-scale settings. Addressing the inefficiencies associated with dosage redundancy, this study proposes a dose coverage planning framework, utilizing MOPSO to solve the multi-objective optimization model for planning UVC dose coverage. Diverging from conventional path planning methodologies, our approach prioritizes the intrinsic characteristics of dose accumulation, integrating a UVC light efficiency factor to mitigate dose redundancy with the aim of reducing energy expenditure and enhancing the efficiency of robotic disinfection. Empirical trials conducted with autonomous disinfecting robots in real-world settings have corroborated the efficacy of this model in deactivating viruses.

Bi-Sb-Te-based thermoelectric materials have the best room-temperature thermoelectric properties, but their inherent brittleness and rigidity limit their application in the wearable field. In this study, W-doped p-type Bi_0.5Sb_1.5Te₃ (W-BST) thin films were prepared using magnetron sputtering on polyimide substrates to create thermoelectric generators (TEGs). Bending tests showed that the thin film has excellent flexibility and mechanical durability, meeting the flexible requirements of wearable devices. W doping can significantly increase the carrier concentration, Seebeck coefficient, and electrical conductivity of BST thin films. At 300 K, the power factor of the W-BST film is 2.25 times higher than that of the undoped film, reaching 13.75 μW cm^-1 K^-2. First-principles calculations showed that W doping introduces significant impurity peaks in the bandgap, in which W d electrons remarkably hybridize with the Sb and Te p electrons, leading to an improved electrical conductivity of BST films. Furthermore, W doping significantly reduces the work function of BST films, thereby improving the carrier mobility. A TEG module fabricated from four layers of W-BST thin films achieved a maximum output power density of 6.91 mW cm^-2 at a temperature difference of 60 K. Application tests showed that the flexible TEG module could power a portable clock using the temperature difference between body temperature and room temperature. At a medium temperature of 439 K, the assembled TEG module can provide a stable output voltage of 1.51 V to power a LED. This study demonstrates the feasibility of combining inorganic thermoelectric materials with flexible substrates to create high-performance flexible TEGs.

Comprehensive Summary: It remains an urgent task to develop alternative hole‐transporting layer (HTL) materials beyond commonly used PEDOT:PSS to increase the shelf‐life of organic solar cells (OSCs). Inorganic metal oxide type materials, such as NiO_x, CoO_x and VO_x, with suitable work functions have attracted numerous research attention recently. In this work, more abundant and easily accessible oxygenated salt, vanadyl sulfate (VOSO₄) has been demonstrated to be excellent choice as HTL for OSCs. The VOSO₄‐based HTL can be readily processed by spin‐coating from the precursor solution with subsequent thermal annealing and UVO treatment. As a consequence, a high power conversion efficiency (PCE) of 18.72% can be achieved for PM8:L8‐BO based OSCs with the VOSO₄‐based HTL. High transmittance, smooth film surface, suitable energy level and high conductivity were revealed to contribute to the high OSC performance. More importantly, compared to device with PEDOT:PSS, VOSO₄‐based OSCs exhibit improved stability when stored in the N₂ filled glove box. After being stored for 600 h, VOSO₄‐based device can retain 89% of its initial efficiency. Notably, VOSO₄ can be used as general HTL in PM6:BTP‐BO‐4Cl and PM6:IT‐4F based OSCs, yielding high PCEs of 17.87% and 13.85%, respectively.