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Ammonia borane (AB) hydrolysis is a sustainable and efficient method for hydrogen energy conversion and transportation. Designing a non-precious AB hydrolysis catalyst with high catalytic activity is considered to be promising but challenging. Herein, highly dispersed Cu0.9Ni0.1 alloy nanoparticles (NPs) were successfully fabricated via a conventional wet-chemical co-reduction method on transition metal carbides (Ti3C2Tx), facilitating hydrogen evolution during AB hydrolysis. The optimized Cu0.9Ni0.1/Ti3C2Tx catalyst exhibits an impressive turnover frequency (TOF) of 2429 h−1 at 323 K for AB hydrolysis, with 100% hydrogen selectivity, outperforming those of most non-precious metal catalysts. This enhanced performance is attributed to the synergistic effect between Cu and Ni, as well as the strong electronic metal–support interaction between Ti3C2Tx and Cu0.9Ni0.1 NPs. This study provides a general and simple method for synthesizing highly efficient non-precious metal AB hydrolysis catalysts. [ABSTRACT FROM AUTHOR]

Black phosphorus (BP) thin film has highlighted its potential in the photoelectric detection field due to its wide-spectrum and high-absorption capacity. However, the fabrication of controllable and highly quality BP film in large dimensions remains a huge challenge. Herein, we creatively fabricated a centimeter-size highly crystalline BP thin film on the bare silicon substrate using a space-confined chemical vapor transport technique, and we in situ constructed a self-driven BP-based metal–semiconductor–metal photodetector. The as-constructed photodetector achieves a high responsivity of up to 500 mA/W, an external quantum efficiency of 42.1%, a maximum specific detectivity of 3.82 × 1010 cm Hz1/2 W−1, and a small noise-equivalent-power of 3.97 × 10−15 W Hz−1/2 under zero bias voltage at 1550 nm illumination. This work provides a strategy to effectively prepare BP thin film for in situ manufacturing self-driven photodetector, which marks a significant step forward in the integration of BP into the industrial settings. [ABSTRACT FROM AUTHOR]

PbS films grown on quartz substrates by the chemical bath deposition method were annealed in an O2 atmosphere to investigate the role of oxygen in the sensitization process at different annealing temperatures. The average grain size of the PbS films gradually increased as the annealing temperature increased from 400 °C to 700 °C. At an annealing temperature of 650 °C, the photoresponsivity and detectivity reached 1.67 A W−1 and 1.22 × 1010 cm Hz1/2 W−1, respectively. The role of oxides in the sensitization process was analyzed in combination with X-ray diffraction and scanning electron microscopy results, and a three-dimensional network model of the sensitization mechanism of PbS films was proposed. During the annealing process, O functioned as a p-type impurity, forming p+-type PbS layers with high hole concentrations on the surface and between the PbS grains. As annealing proceeds, the p+-type PbS layers at the grain boundaries interconnect to form a three-dimensional network structure of hole transport channels, while the unoxidized p-type PbS layers act as electron transport channels. Under bias, photogenerated electron–hole pairs were efficiently separated by the formed p+-p charge separation junction, thereby reducing electron–hole recombination and facilitating a higher infrared response. [ABSTRACT FROM AUTHOR]

The performance improvements of AlGaN‐based deep ultraviolet light‐emitting diodes (DUV‐LEDs) with multigradient electron blocking layer (EBL) and triangular last quantum barrier (LQB) are investigated. The results show that the maximum internal quantum efficiency (IQE) is improved by 44.9% and light output power (LOP) is improved by 58.1% at 200 A cm−2, exhibiting a tremendous improvement compared to the conventional structure. These improvements are mainly attributed to the fact that both multigradient EBL and triangular LQB can generate negative polarization charges in the graded composition layer, which leads to a significant increase in hole concentration compared to the conventional EBL and LQB structures. Meanwhile, the multigradient EBL can transform the conventional triangular barrier into an arc‐shaped barrier, increasing the electron potential barrier height and decreasing the hole potential barrier height. This unique design suppresses electron leakage and enhances hole injection, leading to a significant enhancement of the IQE and alleviation of the efficiency droop. [ABSTRACT FROM AUTHOR]

Black phosphorus (BP), a two-dimensional (2D) van der Waals (vdW)-layered nanomaterial, has attracted explosive study due to the rediscovery of its 2D counterparts (phosphorene) in 2014. Because of its unique structures, superior electrical and optoelectronic capabilities, and compatibility with silicon-based technologies, it is considered a viable material for high-performance photodetection. Controlled ways for the scalable synthesis of good quality large-sized BP are sought to achieve these wonderful expectations, but perfect methodologies are currently lacking. Meanwhile, cutting-edge research shows that the instability of BP under ambient conditions poses a substantial difficulty in a variety of applications. Here, not only an extensive overview of preparation methods but also a summary of the passivation strategy, photoelectric application, and challenges of BP are provided. [ABSTRACT FROM AUTHOR]

Phosphorene nanoribbons (PNRs) combine the flexibility of one-dimensional (1D) nanomaterials with the large specific surface area and the edge and electron confinement effects of two-dimensional (2D) nanomaterials. In spite of the substantial advances in bulk black phosphorus (BP) manufacturing, achieving PNRs without degradation is still a big challenge. In this work, we present a strategy for the space-confined chemical vapor transport synthesis of quasi-one-dimensional surface-passivated monocrystalline PNRs on a silicon substrate. The growth mechanism of the PNRs is proposed by combining experimental results and DFT calculations, indicating that the P4 molecules can break, restructure, and epitaxially nucleate on the surface of the Au3SnP7 catalyst, and finally prefer to grow along the zigzag (ZZ) direction to form PNRs. The low gas flow rate and an appropriate phosphorus molecule concentration allow the growth of PNRs with structural integrity, which can be regulated by the amount of red phosphorus and the confined space. [ABSTRACT FROM AUTHOR]

[Display omitted] • In 2 O 3 -loaded CeO 2 nanorods was applied to hydrogen sensor in the air for the first time. • In 2 O 3 -loaded CeO 2 nanorods exhibited enhanced hydrogen sensing performance. • Enhanced hydrogen sensing performance is due to n-n junction and the larger specific surface area. Hydrogen (H 2) detection sensors based on pure CeO 2 nanorods (NRs) and In 2 O 3 -loaded CeO 2 NRs with different In 2 O 3 contents (5 wt%, 10 wt%, and 15 wt%) were investigated. The crystal phase evolution, morphology features, and response characteristics of the In 2 O 3 -loaded CeO 2 NRs were analyzed in detail using characteristic techniques. Gas sensing results showed that the In 2 O 3 -loaded CeO 2 gas sensors exhibited superior H 2 sensing performances compared with pure CeO 2 NRs under low operating temperature (100 °C). Notably, the gas sensors based on the 10 wt% In 2 O 3 -loaded CeO 2 nanocomposite showed the most refined performance, with response values of 2.79 and 2.43 times higher than those of the pure CeO 2 NRs sensors for 1000 ppm and 4000 ppm H 2 , respectively. The response values exhibited a linear relationship with the detection concentration. Moreover, the In 2 O 3 -loaded CeO 2 gas sensor demonstrated enhanced H 2 selectivity, good recyclability, and long-term stability. Finally, the improved gas sensing mechanism of the In 2 O 3 -loaded CeO 2 gas sensor for H 2 was also proposed. [ABSTRACT FROM AUTHOR]

High-efficiency 278 nm AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) adopting the bidirectional-staircase-barrier (BSB) structure have been investigated. The experimental results show that the maximum external quantum efficiency (EQE) and wall-plug efficiency (WPE) for the proposed BSB structure reach 8.47% and 7.01%, respectively. Furthermore, compared with the reference structure, showing a tremendous improvement of 32% and 31%, respectively. Numerical simulation results show that the BSB structure enhances the electron confinement of the quantum barriers (QBs) as well as improves the hole injection, resulting in a 170% increase in the hole concentration for the active region. Meanwhile, integrating a 2-nm-thick thin-strip-barrier on two QBs close to the p-side can modulate the energy band flatter, which facilitates hole migration and achieves a more uniform distribution of holes in the active region. The more uniform carrier distribution improves the radiative recombination rate of the BSB structure by 147% compared to the reference structure. Furthermore, the dramatic increase of the radiative recombination rate in the three quantum wells (QWs) close to the n-side proves that the BSB structure achieves more QWs to participate in effective radiative recombination, which significantly enhances the quantum efficiency of the DUV-LEDs. • AlGaN-based DUV-LEDs adopt the bidirectional-staircase-barrier structure. • The proposed structure enhances the electron confinement and the hole injection. • Integrating the thin-strip-barrier can modulate the energy band flatter. • The more uniform carrier distribution improves the radiative recombination rate. • The bidirectional-staircase-barrier structure can mitigate the efficiency droop. [ABSTRACT FROM AUTHOR]

Hole transport in InGaN/GaN multiple quantum wells (MQWs) LEDs has been proposed to be insufficient due to relatively large effective mass and low mobility. Here, for the first time, we have direct observed hole overflow from MQWs and enter into InGaN/GaN superlattices (SLs) layer in V-pits-containing GaN-based green LEDs at room temperature. To suppress the hole leakage, an n-AlGaN hole blocking layer (HBL) is inserted between SLs layer and MQWs. The experimental show an interesting and baffling result is that the HBL-containing sample not only exhibits severe hole leakage in high current density range, but also has higher external quantum efficiency (EQE). Numerical simulation reveals that the HBL can change the transportation path of carriers, forcing more electrons injecting from c-plane into the MQWs instead of from V-pit sidewalls. This will increase the carrier concentration in the MQWs, and eventually lead to higher EQE. Meanwhile, less electrons transported through V-pit allowed more holes injecting into deeper layers via V-pit sidewalls, and electroluminescence emission from the SLs layer became stronger when HBL was inserted. • Direct observed hole overflow from MQWs in V-pits-containing green LEDs at room temperature. • Sample with n-AlGaN HBL shows higher EQE at high current density range, even though exhibiting severe hole leakage. • Hole leakage is mainly due to the V-pit-assisted direct hole injection into the deeper layer. • The HBL changes the carrier flow path, reducing nonradiative recombination near the sidewalls of V-pit. [ABSTRACT FROM AUTHOR]

PbSe film used for infrared detection is generally subjected to sensitization at ≤723 K in air, oxygen, and/or iodine vapor for enhancing its optoelectronic performance. In this work, the PbSe film deposited by chemical bath deposition (CBD) method was firstly sensitized at high temperatures (773–848 K) in argon atmosphere. The phase composition, surface and cross-sectional morphologies, carrier concentration and mobility, and detectivity of the PbSe films before and after sensitization were investigated systematically. The optimal PbSe film sensitized at 823 K processes the average grain size of ∼520 nm, carrier concentration of 9.9 × 1016 cm−3, carrier mobility of 13.9 cm2/N·s, and detectivity of 2.31 × 109 Jones for 1550 nm laser radiation. In particular, the optimized PbSe film displays high reproducibility, fast response and excellent high frequency stability. A potential barrier model is proposed to explain the highest optoelectronic performance, where the evaporation of the Se at grain boundaries can generate n-type semiconductor area and the diffusion of oxygen into PbSe grain lattice contributes to inhibit the recombination of carriers. This work provides a new strategy for sensitization of lead chalcogenides thin films. [Display omitted] • The PbSe film was firstly sensitized at high temperature (over 773 K) in Ar. • High reproducibility, fast response and excellent high frequency stability. • The detectivity of 2.3 × 109 Jones is achieved. • A potential barrier model is proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoO 3 /NiO was applied to hydrogen sensor in the air for the first time. • MoO 3 /NiO exhibited enhanced hydrogen sensing performance. • Enhanced hydrogen sensing performance is mainly due to p-n junction. In this work, pure MoO 3 and MoO 3 /NiO nanolamellas are fabricated and their hydrogen sensing properties are investigated for the first time. Various characterization methods are applied to investigate the structural and morphological properties of bare MoO 3 and MoO 3 /NiO nanolamellas. The gas sensing measurement demonstrated that MoO 3 /NiO-5MN exhibited the best hydrogen sensing capability and selectivity to hydrogen. The response of MoO 3 /NiO-5MN was 3.23 toward 1000 ppm hydrogen, which was nearly 1.85 times higher than that of bare MoO 3 at room temperature. The enhanced gas sensing performance of MoO 3 /NiO is mainly due to the p-n heterojunction. [ABSTRACT FROM AUTHOR]