4H-SiC-based polarization-multiplexed metalens balancing high NA and focusing efficiency in near-infrared bands.

High-performance polarization-multiplexed metalenses (PMMs) hold remarkable transformative potential in optical platforms. However, balancing the numerical aperture (NA), focusing efficiency, and spectral bandwidth remains a significant challenge in the existing PMMs, thus restricting their extensive applications. To circumvent these challenges, we theoretically demonstrate two unique orthogonal (linear and circular) PMMs based on all 4H-silicon carbide (4H-SiC) with superior NA, sound focusing efficiency, and broad wavelength range.

Titanium-nitride localized-plasmon hot-electron photodetector covering the entire optical-communication band.

Wide-spectrum photodetectors play a crucial role in applications such as communication, environmental monitoring, and infrared imaging. However, conventional semiconductor-based photodetectors suffer from intrinsic bandgap limitations, restricting the detectable spectral range. Hot-electron photodetectors (HE-PDs) based on plasmon-induced hot-electron transfer (PHET) offer an alternative approach, enabling sub-bandgap photodetection.

Sensitive and Ultrafast Perovskite/Organic Hybrid Photodetectors With a Broad Spectral Response From Ultraviolet to the Telecommunication Band.

Fast and sensitive photodetectors (PDs) with broadband spectral responses are crucial in numerous fields, including image sensing, optical communication, and biochemical applications. While organic PDs offer broadband spectral responses, their response speed is typically limited to the microsecond range. This study demonstrates a sensitive, ultrafast PD with a broad spectral response by combining a 2D perovskite layer with an organic heterojunction of poly[(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b'] dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th) and (2,20-((2Z,20Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,30':4',50]thieno[20,30:4,5]pyrrolo[3,2-g]thieno[20,30: 4,5]thieno[3,2-b]indole-2,10-diyl)bis(me-thanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dima-lononitrile) (Y6) as the active layer.

Radiation-Hardened Position-Sensitive Photodetector Based on Undoped 4H-SiC.

Position-sensitive photodetectors (PSDs) have been widely used for seamless, high-resolution light tracking, but applications such as aerospace and prolonged field operations require stable performance in extreme environments. Conventional PSDs, typically based on the lateral photovoltaic effect of silicon or other semiconductor junctions, are prone to radiation damage and material degradation, limiting their reliability under harsh conditions. Silicon carbide (SiC), with its wide bandgap, high mobility, low defect density, and strong resistance to radiation damage, offers a promising alternative for developing robust detectors.

Imaging ultra-weak UV light below 100 pW cm using a 4H-SiC photodetector with an AlO interfacial layer.

Weak light detection is crucial in various practical applications such as night vision systems, flame monitoring, and underwater operations. Decreasing the dark current of a photodetector can effectively mitigate noises, consequently enhancing the signal-to-noise ratio and overall weak light detection performance. Herein, we demonstrate a 4H-SiC UV photodetector capable of detecting extremely weak UV light.

Detecting Visible to Near-Infrared II Light via CsPbBr Nanocrystals/Y6 Heterojunctions.

In the endeavor to develop advanced photodetectors (PDs) with superior performance, all-inorganic perovskites, recognized for their outstanding photoelectric properties, have emerged as highly promising materials. Due to their unique electronic structure and band characteristics, the majority of all-inorganic perovskite materials are not sensitive to near-infrared (NIR) light. Here, we demonstrate the fabrication of a high-performance broadband PD comprising CsPbBr perovskite NCs/Y6 planar heterojunctions.

High-Quality Solution-Processed Quasi-2D Perovskite for Low-Threshold Lasers.

Spin-coated quasi-two-dimensional halide perovskite films, which exhibit superior optoelectronic properties and environmental stability, have recently been extensively studied for lasers. Crystallinity is of great importance for the laser performance. Although some parameters related to the spin-coating process have been studied, the in-depth understanding and effective control of the acceleration rate on two-dimensional perovskite crystallization during spin-coating are still unknown.

High-Q two-dimensional perovskite topological laser.

Quasi-two-dimensional perovskites have attracted widespread interest in developing low-cost high-quality small lasers. The nano cavity based on topologically protected valley edge states can be robust against special defects. Here, we report a high-quality two-dimensional perovskite topological photonic crystal laser based on the quantum valley Hall effect.

Atomic-level chemical reaction promoting external quantum efficiency of organic photomultiplication photodetector exceeding 10% for weak-light detection.

Low-cost, solution-processed photomultiplication organic photodetectors (PM-OPDs) with external quantum efficiency (EQE) above unity have attracted enormous attention. However, their weak-light detection is unpleasant because the anode Ohmic contact causes exacerbation in dark current. Here, we introduce atomic-level chemical reaction in PM-OPDs which can simultaneously suppress dark current and increase EQE via depositing a 0.

Localized Bound Multiexcitons in Engineered Quasi-2D Perovskites Grains at Room Temperature for Efficient Lasers.

Reducing the excitation threshold to minimize the Joule heating is critical for the realization of perovskite laser diodes. Although bound excitons are promising for low threshold laser, how to generate them at room temperature for laser applications is still unclear in quasi-2D perovskite-based devices. In this work, via engineering quasi-2D perovskite PEA (CH NH ) Pb Br microscopic grains by the anti-solvent method, room-temperature multiexciton radiative recombination is successfully demonstrated at a remarkably low pump density of 0.

Organic Photodetectors with Extended Spectral Response Range Assisted by Plasmonic Hot-Electron Injection.

Organic photodetectors (OPDs) have aroused intensive attention for signal detection in industrial and scientific applications due to their advantages including low cost, mechanical flexibility, and large-area fabrication. As one of the most common organic light-emitting materials, 8-hydroxyquinolinato aluminum (Alq) has an absorption wavelength edge of 460 nm. Here, through the introduction of Ag nanoparticles (Ag NPs), the spectral response range of the Alq-based OPD was successfully extended to the near-infrared range.

Enhancing Hot-Electron Photodetection of a TiO/Au Schottky Junction by Employing a Hybrid Plasmonic Nanostructure.

Hot-electron photodetectors (HEPDs) are triggering a strong surge of interest in applications of image sensors and optics communication, since they can realize photoelectric responses when the incident photon energy is lower than the bandwidth of the semiconductor. In traditional HEPD systems, the metal layers are dressed with regular gratings, which can only excite plasmonic resonance over a narrow bandwidth, limiting the hot-electron photoelectric effect. To break this limitation, hybrid plasmonic nanostructures should be applied in HEPDs.

2D Perovsktie Substrate-Assisted CsPbI Film Growth for High-Efficiency Solar Cells.

High-quality perovskite films are beneficial for fabricating perovskite solar cells (PSCs) with excellent photoelectric performance. The substrate on which the perovskite film grows plays a profound role in improving the crystallization quality of the perovskite film. Here, we proposed a novel method for optimizing CsPbI perovskite films, that is, two-dimensional (2D) perovskite substrate-assisted growth (2D-PSAG) method.

Transfer Printing of Perovskite Whispering Gallery Mode Laser Cavities by Thermal Release Tape.

The outstanding optoelectrical properties and high-quality factor of whispering gallery mode perovskite nanocavities make it attractive for applications in small lasers. However, efforts to make lasers with better performance have been hampered by the lack of efficient methods for the synthesis and transfer of perovskite nanocavities on desired substrate at quality required for applications. Here, we report transfer printing of perovskite nanocavities grown by chemical vapor deposition from mica substrate onto SiO substrate.

Multifunction Sandwich Structure Based on Diffusible 2-Chloroethylamine for High-Efficiency and Stable Tin-Lead Mixed Perovskite Solar Cells.

Low-bandgap tin-lead mixed perovskites (PVKs) are necessary for all-perovskite tandem solar cells. This work proposes a multifunctional sandwich structure with 2-chloroethylamine (CEA) as the top and bottom interface layer and perovskite as the core layer. The sandwich structured CEA allows large ClCHCHNH and small Cl to diffuse into the crystal lattice and grain boundaries of perovskites, endowing an excellent antioxidation property by forming Sn(0), coordinating with SnI, and controlling the perovskite crystallization process.

Boosting Continuous-Wave Laser-Driven Nonlinear Photothermal White Light Generation by Nanoscale Porosity.

The irradiation of an optically absorptive medium by a continuous-wave (CW) near-infrared (NIR) laser can result in a spectral continuum emission covering both the visible and NIR regions, which is attractive for applications as continuum light sources in diverse fields. It is shown here that this NIR-laser-driven light emission can be effectively modulated with nanoscale architecture in the medium. By using porous silica as the model matrix and Yb ions as the photothermally active centers, up to 100 folds increment in NIR-laser-induced emission intensity and dramatic decrease in threshold excitation density are demonstrated.

Sunlight-Activated Orange Persistent Luminescence from Bi-Doped SrBaZnGaO for Warm-Color Optical Applications.

A warm persistent luminescence (PersL) material SrBaZnGaO:Bi was prepared using the conventional high-temperature solid-phase reaction method. We first investigated the PersL properties of SrBaZnGaO:Bi in detail via PersL spectra, PersL excitation spectrum, PersL decay curves, and thermoluminescence (TL) spectra. The highlight of this study is that in addition to the 254 nm light source, the low-energy light source of 365 nm and sunlight can effectively excite electrons and charge traps, resulting in preferable orange PersL performance.

Interface modification of an electron transport layer using europium acetate for enhancing the performance of P3HT-based inorganic perovskite solar cells.

In recent years, although the power conversion efficiency (PCE) of thermally stable all-inorganic CsPbI perovskite solar cells (PSCs) had shown a great progress, the most reported CsPbI PSCs suffered from the large open-circuit voltage () loss, which is related to severe nonradiative recombination and a mismatch in energy level at the transport layer/perovskite interface. In this work, europium acetate (EuAc) as a multifunction interface material is chosen to modify the TiO/perovskite interface, the crystal quality of CsPbI perovskite films is improved, and both bulk and interfacial defects are reduced effectively. Meanwhile, the energy levels arrangement between TiO and CsPbI perovskites is also optimized, corresponding the raised built-in electric field afford a strength force to accelerate the transport and extraction of charge carriers from CsPbI perovskites to TiO.

Application of quantum dots in perovskite solar cells.

Perovskite solar cells (PSCs) are important candidates for next-generation thin-film photovoltaic technology due to their superior performance in energy harvesting. At present, their photoelectric conversion efficiencies (PCEs) are comparable to those of silicon-based solar cells. PSCs usually have a multi-layer structure.

Interface Modification of a Perovskite/Hole Transport Layer with Tetraphenyldibenzoperiflanthene for Highly Efficient and Stable Solar Cells.

Interface engineering has been recognized as a very effective method to simultaneously improve both efficiency and stability in perovskite solar cells (PSCs). In this work, we report using an excellent small molecular material tetraphenyldibenzoperiflanthene (DBP) to modify the perovskite/Spiro-OMeTAD interface to achieve significantly improved solar cell performance. It is found that the ultrathin DBP interlayer accelerates hole transfer across the FAMAPbIBr/Spiro-OMeTAD interface and effectively reduces the nonradiative recombination.

High performance flexible organic photomultiplication photodetector based on an ultra-thin silver film transparent electrode.

Flexible and lightweight photomultiplication-type organic photodetectors (PM-OPDs) have attracted wide attention for their broad application prospects, especially in the field of wearable electronic products. However, the commonly used indium tin oxide (ITO) conductive anode is not conducive to realize high-performance flexible PM-OPDs due to its rigidity and fragility. Here, on the flexible polyethylene terephthalate (PET) substrate, we successfully fabricate highly sensitive poly 3-hexylthiophene:phenyl-C-butyric acid methyl ester (P3HT:PCBM, 100:1) based PM-OPDs using ultra-thin silver films as transparent anodes.

Broadband and wide-angle light absorption of organic solar cells based on multiple-depths metal grating.

A silver grating containing three grooves with different depths in one period was proposed as the back electrode for improving light absorption in organic solar cells. We found that the broadband absorption enhancement of the active layer covering the visible and near-infrared bands can be obtained due to the excitation of surface plasmon resonance and the multiple resonances of cavity mode. The integrated absorption efficiency of the proposed structure under TM polarization between 350 nm to 900 nm is 57.

Research Progress in Organic Photomultiplication Photodetectors.

Organic photomultiplication photodetectors have attracted considerable research interest due to their extremely high external quantum efficiency and corresponding high detectivity. Significant progress has been made in the aspects of their structural design and performance improvement in the past few years. There are two types of organic photomultiplication photodetectors, which are made of organic small molecular compounds and polymers.

High Performance Ultrathin MoO₃/Ag Transparent Electrode and Its Application in Semitransparent Organic Solar Cells.

In this paper, we demonstrate high performance ultrathin silver (Ag) transparent electrodes with a thin MoO₃ nucleation layer based on the thermal evaporation method. The MoO₃/Ag transparent electrodes fabricated at different deposition rates were compared systematically on aspects of the transmission spectrum, surface resistance, and surface morphology. Our study indicates that with the presence of the MoO₃ nucleation layer, an Ag film of only 7 nm thick can achieve percolation and the film is porous instead of forming isolated islands.