In recent years, position-sensitive detectors (PSDs) have found widespread application in displacement measurement, optical measurement, imaging, and laser communication, owing to their high spatial resolution and rapid response capabilities. However, the performance and operating mechanisms of perovskite-based PSDs remain insufficiently elucidated. In this work, we fabricated a high-sensitivity self-powered PSD based on a ZnO/P(VDF-TrFE)−CH₃NH₃PbI₃(MAPbI₃) heterojunction. Systematic optimization revealed an optimal P(VDF-TrFE) doping concentration of 5 mg/mL, enabling the device to achieve a remarkable positional sensitivity (PS) of 307.03 mV/mm with a minimum nonlinearity of 1.02%. Furthermore, the intrinsic pyroelectric property of P(VDF-TrFE) induces a significant pyroelectrically enhanced lateral photovoltaic effect (LPE), boosting the PS to 511.33 mV/mm—an enhancement of 166.5%. The heterojunction PSD maintains effective operational performance over an electrode spacing range of 0.5−2.2 mm. While the LPE response declines with increasing spacing, a considerable pyroelectric effect (PE)-enhanced PS of 70.67 mV/mm is retained even at 2.2 mm. Importantly, we demonstrate multi-wavelength imaging by exploiting both the inherent LPE response and its pyroelectrically enhanced counterpart, with imaging intensity tunable via electrode spacing control. This study provides crucial insights into the LPE behavior of the heterojunction and systematically clarifies the mechanism by which the PE modulates device performance and imaging capabilities.

The integration of proximity sensing into flexible tactile electronic skins (e-skins) represents a fundamental shift from conventional contact-only interfaces toward anticipatory perception systems. This mini-review provides a systematic examination of recent advances in proximity-augmented e-skins, which overcome the inherent latency of tactile sensors by extending sensory awareness into the pre-contact domain. We provide a comprehensive overview of five key sensing modalities—capacitive, triboelectric, magnetic, temperature-based, and humidity-based—detailing their operating principles, material innovations, and structural optimization strategies. System-level requirements for practical deployment are also critically analyzed. Representative applications in interactive surfaces, human–robot collaboration, soft robotics, healthcare monitoring, and integrated multifunctional e-skins are highlighted to illustrate the transformative potential of this technology. Despite substantial progress, challenges persist in seamless multimodal integration, scalable manufacturing, and intelligent data fusion. Future directions are discussed to realize robust, perceptually intelligent e-skins that bridge the gap between laboratory innovations and real-world applications.

Systematic optimization of the delayed self-heterodyne method for laser frequency noise characterization is investigated across an extensive linewidth range (100 Hz to 10 MHz). By evaluating various fiber lengths, window functions, and five demodulation algorithms, we identify a critical trade-off: long fibers enhance sensitivity for narrow-linewidth lasers but exacerbate spectral leakage in broad-linewidth sources. Our findings demonstrate that Hanning and Blackman windows effectively suppress this leakage, ensuring measurement consistency across different delay lengths. Among the evaluated algorithms, the Hilbert transform offers the superior balance of high-frequency accuracy and computational efficiency. Validated under low-power conditions, this optimized framework provides a robust and power-independent methodology for precise FN analysis, offering significant guidance for high-performance laser development.

Fluorescence temperature sensing technology has become a research direction in the field of temperature measurement with its significant advantages of non-contact measurement, high spatial resolution, fast response and anti-electromagnetic interference. Although the double rare earth ion doping ratio fluorescent temperature sensing materials have made significant progress, the thermal quenching phenomenon is still the key bottleneck restricting its performance improvement. In this study, we propose to construct a flexible Sc₂Mo₃O₁₂:Eu³⁺/Tb³⁺ film with negative thermal expansion characteristics, and systematically study its visual temperature sensing characteristics. The negative thermal expansion characteristics of Sc₂Mo₃O₁₂ matrix effectively inhibited the thermal quenching rate of Tb³⁺ luminescence, and enhanced the thermal enhanced luminescence effect of Eu³⁺. This two-way regulation mechanism improves the intensity comparison of the two light-emitting channels, and provides an innovative strategy for improving the sensitivity of temperature sensing. The flexible film based on Eu³⁺/Tb³⁺ codoped system realizes intuitive temperature perception through the significant change of fluorescent color, and can complete the temperature interpretation without complex spectral equipment. This greatly expands its application prospect in the field of rapid field detection and real-time monitoring, and shows its broad potential in the fields of wearable devices, biomedical diagnosis, and real-time monitoring of surface temperature field.

Achieving high emission efficiency at low current densities remains a challenge for micro-LEDs. Here, we demonstrate a controllable interfacial strategy by tuning the annealing temperature of RF-superimposed DC sputtered ITO to modulate carrier injection dynamics. STEM analysis reveals 500 °C annealing triggers discrete substitutional In-atom incorporation into the p-GaN lattice, forming localized nanoscale contact regions. This architecture induces a localized carrier injection mechanism that significantly enhances the efficiency of micro-LEDs at low current densities. Specifically, the 500 °C-annealed 10 μm devices exhibit a dramatic enhancement in light output power (LOP), reaching 1.3 × 10⁻¹ mW at 5 A/cm², which is significantly higher than the 5.3 × 10⁻⁴ mW measured for 700 °C-annealed devices. Furthermore, the peak efficiency current density (J_peak) is dramatically shifted from 140 to 17 A/cm² for 5 μm devices. Capacitance−voltage analysis further corroborates the localized carrier injection mechanism. These findings establish contact interfacial modulation as a robust strategy for optimizing micro-LEDs in low-power display applications and tailoring device-level performance across broader optoelectronics.

With the widespread application of artificial intelligence (AI) computing in low-temperature scenarios such as deep space and deep sea, RRAM-based edge computing has gradually attracted attention. In this paper, an adaptive reference conductance algorithm (ARCA) is proposed to improve the inference accuracy in low-temperature scenarios due to the conduction drift. The RRAM CIM chips with high read cycles are fabricated based on 28 nm CMOS logic technology, and the read times could reach 10¹². By studying the influence of conductance drifting on inference accuracy in low temperature, a model of temperature and optimal reference conductance is proposed. Furthermore, by this model, adaptive selecting optimal reference conductance of analog-to-digital converters (ADCs) to quantize column current of RRAM array under different temperatures. At −40 ℃, the reference accuracy could increase from 75.43% to 86.8%.

We have systematically studied the impact of thickness on the electrical properties of thin GaN channels on N-polar AlN (0001) templates grown on sapphire. The observed increase in sheet carrier density with increasing GaN thickness can be quantitatively reproduced by calculations assuming a Fermi-level pinning about 0.8 eV below the conduction band. The mobility strongly increases until 6 nm which correlates with reduced overlap of the 2DEG wave function with the surface layer. The mobility then increases more gradually up to 10 nm, corresponding to a reduced fraction of the 2DEG within the first 0.5 nm near the AlN/GaN interface, namely, the region affected by interface roughness. The mobility saturates at approximately 400 cm²·V⁻¹·s⁻¹, probably limited by dislocations and the overlap with deep traps inside the AlN back barrier. If the GaN thickness exceeds 15 nm, the mobility decreases, likely due to the onset of gradual relaxation and appearance of misfit dislocations. Finally, we note that the temperature-dependent mobility exhibits an unexpected contribution proportional to $ T^{-2} $ for all GaN channels on N-polar AlN, including those reported in the literature. Such observation may be explained by a 50% higher effective mass of the electron, which amplify the electron−phonon scattering, ultimately limiting the room-temperature mobility to about 750 cm²·V⁻¹·s⁻¹ and confining the sheet resistivity to values above 200 Ω/□.

Ⅲ-nitride semiconductors with continuously tunable bandgaps are promising for white light emission and full-color displays. The mainstream RGB LED integration approach suffers from low long-wavelength efficiency and complex packaging. Herein, we demonstrate a novel single-chip dual-wavelength LED structure, which integrates blue (upper) and green (bottom) multiple quantum wells (MQWs) separated by a GaN intermediate spacer layer. The device exhibits two distinct emission peaks at 446 and 528 nm, with excellent luminescence stability. We investigate the role of the spacer layer and reveal its critical effect on the carrier distribution and radiative recombination behavior. The maximum wall-plug efficiency (WPE) of the device reaches approximately 36.7%, and its abnormal droop curve indicates a transition of the green emission mechanism from electroluminescence (EL) to photoluminescence (PL). By tuning the injection current, the dual-wavelength LED achieves a continuous color transition from green to blue, which corresponds to chromaticity coordinates ranging from (0.2584, 0.7098) to (0.1771, 0.2649) in the CIE 1931 chromaticity diagram. This work provides a feasible and flexible strategy for emission color modulation, and also lays a foundation for the development of high-performance solid-state lighting devices.

Achieving aluminum nitride (AlN) epilayers with dislocation densities below 10⁷ cm⁻² on sapphire remains critical for ultraviolet (UV) optoelectronics applications. However, the lattice and thermal mismatches inherent to heteroepitaxial growth hinder the simultaneous suppression of threading dislocations and surface cracking. In this work, a 10.2-μm-thick, 4-inch AlN film was fabricated on an AlN/sapphire substrate. A strain-modulated buffer was embedded beneath the AlN epilayer to pre-introduce a well-balanced compressive strain, which counteracted tensile strain accumulation during thick-layer growth while maintaining continuous two-dimensional epitaxy for effective defect suppression. This strain management strategy, combined with progressive dislocation annihilation as the layer thickness increased, yielded a surface dislocation density of 7.6 × 10⁶ cm⁻² and limited cracking to within approximately 2 mm from the wafer edge. This scalable and cost-effective approach enables the growth of crack-suppressed, high-quality AlN epilayers on sapphire, offering a practical pathway for UV optoelectronic devices in light of the current limitations of bulk AlN substrates.

Electrode design is critical for the performance and reliability of flip-chip AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs). We propose a semi-surround n-electrode design to achieve better current spreading for a relatively small DUV LED with a size of 8×15 mil². It is found that an optimal semi-surround n-electrode can reduce the operating voltage and increase the chip reliability due to the larger ohmic contact area. Moreover, the semi-surround n-electrode introduces multiple current injection paths, which causes the improvement of the current spreading in both the directions parallel (X) and perpendicular (Y) to the electrode fingers. However, an excessively long semi-surround n-electrode will decrease the light output power because of the severely reduced active region area. Furthermore, experiments and simulations reveal that the semi-surround n-electrode can improve the current spreading in the Y direction at high injection current. Meanwhile, it is also found that a short semi-surround n-electrode causes deteriorated current spreading in the X direction due to the unbalanced resistance between n-electrode and p-electrode. Our work highlights the importance of two-dimensional current management in electrode design and provides a practical strategy for developing high-performance and reliable DUV LEDs with a relatively small chip size.

Single-photon avalanche diode (SPAD) image sensors are widely used in direct time-of-flight (D-TOF) imaging, but their ranging performance is often constrained by limited laser power. This article presents a SPAD-based D-TOF imaging system that combines a reconfigurable macro-pixel sensor architecture with a lightweight depth completion algorithm to achieve long-range depth imaging with enhanced spatial resolution under low optical power. The proposed sensor adopts a back-side illuminated (BSI) 3D-stacked architecture with programmable macro-pixels that enhance detection sensitivity and enable flexible sensitivity–resolution trade-offs. An injection-locked ring-oscillator-based time-to-digital converter (RO-TDC) array achieves a time resolution of 152.5 ps, enabling accurate TOF measurement at an optical power of 10 mW. To compensate for macro-pixel-induced resolution loss, a probabilistic normalized convolutional neural network (pNCNN) is employed for depth completion using sparse depth inputs only. Experimental results demonstrate that up to 30 × effective resolution enhancement of the system can be achieved via the depth completion algorithm without changing the physical resolution of the sensor. Additionally, the proposed system achieves a maximum ranging distance of 90 m and a range-to-power figure-of-merit (FOM) of 9 m/mW, which validates the effectiveness of the system.

In this article, a vertical SnO/β-Ga₂O₃ mesa heterojunction diode (mesa-HJD) fabricated through self-aligned etching is reported. The mesa structure eliminates the influence of lateral depletion at the region, leading to an improved breakdown characteristics in comparison with its unterminated heterojunction diode (UT-HJD) counterpart. The SnO/β-Ga₂O₃ mesa-HJD, featuring a 500 nm mesa depth, achieves a breakdown voltage (BV) of 1100 V, which can be improved to 1631 V by sidewall passivation. With the increase of mesa depth, BV increases, accompanied by the increase of specific on-resistance (R_on,sp). Therefore, a maximum Baliga’s power figure of merit (PFOM) can be achieved for the optimized device with 500 nm mesa depth, giving the value of 0.93 GW/cm² for the passivated device. The mesa-HJD demonstrates considerable potential for application in high BV β-Ga₂O₃ power electronic devices in the future.

Large-area perovskite solar cell modules efficiency remains lower than small-area devices, perovskite crystallization between small and large areas difference could be one reason. Previously, diluted solution was often used to reduce viscosity to achieve uniform perovskite thin films, but this approach could narrow the crystallization window and leave insufficient time for controlled crystal growth. Meanwhile, insufficient solute supply often results in interrupted material availability for grain growth, leading to the formation of excessive small crystal nuclei and thus poor thin-film quality. Here, we developed a strategy that use a bi-functional group additive to stabilize the δ-FAPbI₃ intermediate phase, which delays the direct and rapid conversion of lead iodide into α-FAPbI₃ during large-area perovskite film growth. Based on this strategy, the efficiencies of perovskite modules with aperture areas of 14.6, 70.5, and 285.6 cm² developed in this work are 24.4% (certified steady-state efficiency: 24.4%), 23.1%, and 22.4%, respectively. The efficiency loss per order-of-magnitude increase in area was reduced from 2.0% to 1.3%, which is approaching the state of the art of traditional thin-film CdTe solar cells (0.8%). In addition, the large-area module (155 cm²) retained 86% of its initial efficiency after 1053 h of maximum power point (MPP) tracking.

Spin-orbit torque (SOT) is widely considered as the key technology for next-generation magnetic random-access memory (MRAM), leveraging ultrafast operating speed and unlimited endurance. However, integrating perpendicular magnetic anisotropy (PMA) SOT-MRAM stacks with the back-end-of-line (BEOL) thermal budget remains a critical challenge, as PMA degradation and Pt-Fe interdiffusion typically occur under 400 °C annealing. Here we propose a double CoFeB reference layer (DCFB) structure to address these issues. The additional CoFeB reference layer and two extra CoFeB/W interfaces significantly enhance the PMA of the reference layers, while improving the crystallization of the overlying Pt/Co multilayers. Furthermore, the DCFB stack effectively acts as a diffusion barrier against Pt-Fe interdiffusion. Consequently, a fabricated magnetic tunnel junction (MTJ) incorporating the DCFB stack achieves a high tunneling magnetoresistance (TMR) of 137% even after annealing at 400 °C. Our work provides a robust, simplified approach for the design of SOT-MRAM stacks with BEOL thermal budget tolerance.

Antimony selenosulfide (Sb₂(S,Se)₃) is a promising photovoltaic absorber material for both outdoor and indoor application scenarios. Nevertheless, the performance of Sb₂(S,Se)₃ solar cells remains constrained by the severe interface trap-induced nonradiative recombination. Interface engineering has been recognized as an effective approach to suppress recombination and boost charge transport. In this work, we introduce an organic modifier (O-BDT) between Sb₂(S,Se)₃ absorber and hole transport layer. The theoretical and experimental results evidence that O-BDT can simultaneously passivates interface defects and optimizes the energy-level alignment, leading to a significantly reduced voltage loss. Finally, the O-BDT modified solar cell achieves a power conversion efficiency (PCE) of 8.01% under AM 1.5G illumination. Moreover, the device delivers a PCE of 19.04% under 1000 lux, 3312 K LED lighting, among the best list of IPVs based on antimony chalcogenide compounds.

Impact ionization probabilities were calculated in a CdHgTe quantum well, where the distance between electron subbands is close to the band gap energy. This band structure enables impact ionization with small momentum transfer for electrons in the second subband. The study demonstrates that such processes increase the impact ionization probability by approximately two orders of magnitude compared to the impact ionization probability for electrons in the first subband, for which transitions with small momentum changes are impossible. The probability of single impact ionization during the electron energy loss due to optical phonon emission is estimated. Experimental methods for detecting impact ionization in this structure are discussed.

Integrating electrochromic (EC) and photochromic (PC) functions within a single material system holds great significance for the development of next-generation intelligent responsive materials. Traditional organic photochromic materials are all small molecules and oligomers, which require the photochemical response of specific photosensitive groups. However, PEDOT:PSS, a classic electrochromic polymer, has never been reported to exhibit photochromic properties due to the absence of photosensitive groups. Herein, we report for the first time the photochromic properties of PEDOT:PSS films, demonstrating their simultaneous capability of multi-field coupling response in the aspects of light, electricity and chemistry. The composite film undergoes a rapid color change from light blue to dark blue under ultraviolet light irradiation. This is attributed to the transformation process from the bipolarons state to the polarons state in the PEDOT:PSS, induced by photogenerated electrons as confirmed by EPR and Raman analyses. Furthermore, the developed hydrogel system enhances charge separation, yielding a 30.1% relative transmittance change and month-long stability. This work fills the long-standing gap in the understanding of the photochromic and electrochromic mechanisms of PEDOT:PSS, providing fundamental insights into carrier dynamics at organic−inorganic interfaces and laying the foundation for the development of multi-mode stimuli-responsive devices.

High performance flexible pressure sensors, as a very important group of electronic component for information transmission and collection, have gained widespread attention. Herein, Ti₂CT_x MXene nanosheets were vertically grown on carbon cloth substrate (Ti₂CT_x@CC) via the simple sintering and subsequent etching process. Flexible pressure sensors featuring the Ti₂CT_x MXene nanosheets as the sensitive material were then fabricated using polyvinylidene fluoride (PVDF) film weaved by the electrospinning route between the sensitive material and the interdigital electrodes to improve the sensitivity. As-fabricated flexible sensor exhibited superior performances including high sensitivity up to 3109.2 kPa⁻¹, good response and recovery time of 80/80 ms, and favorable stability over 8000 loading/unloading cycles. Boasting the high sensitivity across a broad range, the sensor can in real-time capture a spectrum of human activities—from the faint pulse signal to the large pressure of joint activities and shows promising capability for mapping spatial pressure distribution.