Academy of Opto-Electronics

Perovskite solar cells (PSCs) have attracted considerable scientific interest due to their remarkable power conversion efficiency (PCE) and economically viable manufacturing processes. However, the commercialization has faced obstacles such as limited operational stability and susceptibility to moisture, which usually stem from the inferior quality of perovskite film. In this study, we present Di-p-toluenesulfonamide (D-pTSAD) as triple-functional ligand featuring multi-site synergistic coordination with the perovskite lattice. Through this mechanism, D-pTSAD simultaneously facilitates oriented crystal growth and mitigates defect formation, achieving a top-performing device with a PCE of 26.22%. Comprehensive analysis reveals that D-pTSAD forms stronger coordination with both Pb2 + and I- ions compared to bifunctional ligands, effectively passivating defects, suppressing ion migration, and reducing nonradiative recombination. After 1,000h of continuous maximum power point tracking, PSCs with D-pTSAD maintained 82.5% of initial PCE. This research underscores the potency of multisite coordination chemistry in elevating both performance and stability of PSCs.

ABSTRACT InP/InGaAs‐based heterojunction phototransistors (HPTs) are promising for ultrasensitive short‐wave infrared (SWIR) detection due to their high internal gain, low excess noise, and low power consumption. This work demonstrates an HPT achieving a high optical gain of ∼1200 at −2 V bias, with dark current lower than state‐of‐the‐art avalanche photodiodes (APD). To further push its sensitivity to the limit for weak light/ultra‐long‐distance imaging, the noise mechanism in low frequency (LF) regime and its origins have been investigated, by which generation current in depletion region caused by the defect‐related traps is explored and studied. In particular, the LF noise power is found to be independent of the internal gain. A Hooge's constant of 2.1 × 10 −5 is reported for the first time in gain‐based detectors, comparable to HgCdTe devices. Remarkably, temperature‐dependent multi‐level random telegraph signal (RTS) analysis reveals two dominant origins of the generation current, corresponding to relaxation processes of two typical types of mid‐gap traps. One is Zn‐related extrinsic defects caused by Zn diffusion into the InP emitter, while the other is Ga‐related intrinsic defects in InGaAs collector. As the guideline for optimizing the HPT detector design, this work paves the way to further improve the sensitivity for low‐flux SWIR photodetection.

ABSTRACT Revolutionary optical imaging enabled by vectorial and flat optics marks a transformative paradigm that unites subwavelength photonic engineering, full‐vector light‐field control (amplitude, phase, and polarization), and planar optical architectures. Conventional imaging systems, constrained by curved‐optics geometry and scalar diffraction theory, face intrinsic trade‐offs among spatial resolution, field of view (FOV), and system compactness. By harnessing flat optical elements such as metasurfaces and catenary‐phase devices together with vectorial manipulation, this emerging field transcends those limitations. The review highlights three fundamental breakthroughs: (1) Abrupt phase shifts in subwavelength scale enabling ultrathin, wide‐FOV planar imaging; (2) Evanescent–propagating wave conversion under appropriate near‐field coupling conditions, and vectorial optical synthetic apertures achieving far‐field super‐resolution beyond the diffraction limit; (3) Computational optics that integrates sensing and computing in a unified physical platform. These advances enable intelligent, programmable imaging systems that transcend the limitations of traditional optics, with applications spanning biomedical nanoscopy, remote sensing, and quantum information.

ABSTRACT In this paper, a large‐diameter diffuse argon plume is generated through being excited by a negatively‐biased sinusoidal voltage. The diffuse plume increases in length with increasing peak voltage and argon flow rate, which transitions to a nonuniform plume when voltage amplitude exceeds a threshold. The diffuse plume initiates at the rising voltage edge, while the nonuniform plume initiates at the rising and falling edges. From fast photography, the diffuse plume originating from the discharges at the rising voltage edge is speculated to operate in a Townsend discharge regime, while the discharge at the falling voltage edge is filamentary in the nonuniform plume. By optical emission spectroscopy, plasma parameters including electron temperature, electron density, and atomic oxygen concentration have been investigated.

ABSTRACTThe success of data-driven deep learning in computational imaging is often constrained by the need for extensive labeled datasets. Recent progress in physics-informed neural networks has mitigated this issue by integrating analytical physical models, allowing data-free training. However, for challenging imaging tasks, such as to simultaneously acquire complex amplitude light-field information, the weak physical constraints of conventional imaging hardware largely limit the spatiotemporal imaging resolution. Here, we propose an extremely simple yet powerful monocular camera for complex amplitude imaging based on a liquid-crystal (LC)-lens-informed Fourier neural network. Combining a polarization-multiplexed bifocal LC lens with a polarization image sensor, the camera acts as a polarization phase-shifting radial shearing interferometer. Without any labeled data, the LC-lens-informed Fourier neural network can reconstruct the complex amplitude of a variety of scenes from captured polarization images in a single shot with high fidelity. We experimentally demonstrate the reconstruction of wavefront aberrations involving 136 Zernike modes with a phase accuracy of λ/35 as well as static hologram retrieval and dynamic monitoring of air flow and flame fields. This complementary hardware-algorithm framework offers a promising pathway for developing compact, versatile and high-performance complex amplitude imaging systems for adaptive optics, hologram reconstruction and material diagnosis applications.

ABSTRACT Transition metal oxides (TMOs) such as MoO x , featuring a high work function and a wide optical bandgap, are competitive alternatives to p‐type a‐Si:H or nano crystalline silicon in silicon heterojunction solar cells to form silicon compound heterojunction (SCH) solar cells. However, the thermal instability of MoO x during the curing process of screen‐printing restrains its massive production in industry. In this work, silver grids are printed on the MoO x side of MoO x SCH solar cells, and the influence of annealing atmosphere and temperature on the performance of the solar cells is investigated. After annealing in O 2 or air, the device performance is significantly degraded, while it remains almost unchanged after annealing in N 2 at 136°C. A conversion efficiency of 22.40% is achieved on the SCH solar cells with screen‐printed Ag grids when annealed at 136°C for 40 min in N 2 atmosphere, which is equivalent to that of the solar cells with thermally evaporated grids. To reveal the annealing effect, systematic research is conducted on changes in optoelectronic property, contact resistivity, and compositional distribution of MoO x , brought about by annealing in N 2 , O 2 , and air at different temperatures. Oxygen vacancies and conductivity both increase after annealing in N 2 , contributing to more efficient hole carrier collection through defect state‐assisted band‐to‐band transition. However, dipoles formed at the c‐Si/MoO x interface during N 2 annealing, proposed according to the calculation of differential charge density, might hinder the hole transportation from c‐Si to MoO x . A 1‐nm Al 2 O 3 layer inserted between a‐Si:H(i) and MoO x is found to be effective for mitigating the V oc drop after annealing in air. The approaches exhibit great potential for implementing screen‐printing on MoO x SCH solar cells, rendering industrial production of MoO x SCH solar cells feasible.

Abstract To overcome Boltzmann thermal limitation, the study investigates isolated‐state field‐effect transistors based on armchair SnSe nanoribbons using first‐principles calculations and quantum transport simulations with various edge passivation strategies, particularly fluorine (‐F) passivation. The results show that ‐F passivation enabling sub‐60 mV decade −1 switching behavior. Key parameters including E sub‐Gap , E Gap , and Δ E play a crucial role in device performance improvement. By introducing asymmetric underlap (UL), the design achieves a steep subthreshold swing (SS) of 46 mV decade −1 and an ON‐state current of 502 µA µm −1 . Compared to symmetric UL, asymmetric UL designs enable better device integration and enhanced performance, thereby meeting the scaling requirements for advanced devices. Further performance enhancement is realized through strain engineering: a 2% uniaxial tensile strain reduces the carrier effective mass and improves band alignment, increasing ON‐state current to 644 µA µm −1 . Incorporating a gate‐all‐around FETs further boosts the current to 796 µA µm −1 without strain and up to 1019 µA µm −1 with strain, while maintaining SS below 60 mV decade −1 , satisfying the International Technology Roadmap for Semiconductors requirements for both high‐performance and low‐power devices. The findings provide theoretical guidance for MOSFET‐based devices with both steep SS and enhanced ON‐state currents, contributing to the advancement of electronic technologies.