Search

Two-dimensional (2D) transition metal dichalcogenides (TMDs) hold immense promise as ultrathin-body semiconductors for cutting-edge electronics and optoelectronics. In particular, their sustained charge mobility even at atomic-level thickness as well as their absence of surface dangling bonds, versatile band structures, and silicon-compatibility integration make them a prime candidate for device applications in both academic and industrial domains. Despite such high expectations, group-VI TMDs reportedly exhibit a range of enigmatic properties, such as substantial contact resistance, Fermi level pinning, and limited unipolar charge transport, which are all rooted in their inherent defects. In other words, intrinsic physical properties resulting from their native defects extend their influence beyond the material level. Bridging point-defect-induced material properties and their behavior at the device level, this Perspective sheds light on the significance of crystalline defects beyond a rather simple defect–property relationship. As a distinctive approach, we briefly review the well-established defect model of conventional III–V semiconductors and further apply it to the emergent defect behaviors of 2D TMDs such as their defect-induced gap states. Within the main discussion, we survey a range of behaviors caused by the most prevalent intrinsic defect, namely, vacancies, within 2D TMDs, and their implications for electronic and optoelectronic properties when employed at the device level. This review presents an in-depth summary of complexities in material properties as well as device characteristics arising from intrinsic point defects and provides a solid foundation for the cross-links among native defects and material/device properties. [ABSTRACT FROM AUTHOR]

This work investigates exciton localization and dynamics in semiconductor GaNAsP nanowires (NWs) with varying nitrogen concentrations. Through detailed time-resolved photoluminescence studies, we identify a nitrogen composition-dependent difference in exciton transfer between localized states formed due to alloy disorder. With [N] = 0.1%, the localized states exhibit cluster-like, non-interacting behavior, whereas at [N] = 1.1%, a continuous band of localized states is observed. Additionally, the phosphorous incorporation in the NWs appears to enhance the exciton spatial confinement compared to behaviors observed in phosphorous-free GaNAs NWs, emphasizing the role of the alloy composition in the nature of exciton localization. Temperature is highlighted as a significant factor affecting exciton mobility, enabling efficient transfer between the localized states at higher temperatures. This, in turn, influences exciton lifetimes. Our findings, therefore, shed light on the nature of exciton dynamics in GaNAsP NWs, enriching our understanding of these materials and paving the way for their applications in optoelectronics. [ABSTRACT FROM AUTHOR]

Chiral hybrid lead halide perovskites show interesting chiral optoelectronic properties. The extent of chirality is often estimated by their circular dichroism (CD) response. Here, we show that the CD data depend strongly on film morphology. Four of the six chiral hybrid lead halide films prepared, 2D (R- and S-MBA)2PbI4 and 1D (R- and S-MBA)PbI3 (MBA: methylbenzylammonium), form homogenous non-textured films and show an isotropic CD signal. In contrast, the other two samples, 1D (R- and S-MBA)PbBr3, form textured films, showing uncorrelated CD signals from different parts of the film. Therefore, the role of film morphology needs to be verified before designing and comparing the chiroptic and chiral optoelectronic properties of hybrid perovskites. [ABSTRACT FROM AUTHOR]

Nanosheets of transition metal dichalcogenides with prospects of photocatalysis and optoelectronics applications have significant potential in device fabrication due to their low-cost production and easily controllable morphology. Here, non-degenerate pump-probe differential transmission studies with varying pump-fluence have been carried out on single-phase 2H–MoSe2 and mixed-phase 1T/2H–MoSe2 nanosheets to characterize their excited carrier dynamics. For both the samples, the differential probe transmission data show photo-induced bleaching at earlier pump-probe delay followed by photo-induced absorption unveiling signatures of exciton-state filling, exciton trapping, defect-mediated photo-induced probe absorption and recombination of defect bound excitons. The exciton trapping and photo-induced absorption by the trapped-carriers are estimated to occur with time constant of ∼430 to 500 fs based on multi-exponential modelling of the differential transmission till pump-probe delay of ∼3.5 ps. Biexponential modeling of the subsequent slow-recovery of the negative differential transmission at pump-probe delay ≳3.5 ps reveals that the exciton recombination happens via two distinct decay channels with ∼25 to 55 ps (τ1) and ≳1 ns (τ2) time constants. Pump-fluence dependent reduction in τ1 and further modelling of exciton population using higher order kinetic rate equation reveals that the two-body exciton-exciton annihilation governs the exciton recombination initially with a decay rate of ∼ 10 − 8 cm3s−1. The detailed analysis suggests that the fraction of total excitons that decay via long decay channel decreases with increasing exciton density for 2H–MoSe2, in contrast to 1T/2H–MoSe2 where the fraction of excitons decaying via long decay channel remains constant. [ABSTRACT FROM AUTHOR]

γ-GeSe has recently emerged as a promising material for electronics and optoelectronics due to its unique band structure and excellent electrical properties. However, controllable growth of γ-GeSe remains a significant challenge. In this work, the controllable growth of γ-GeSe microflakes (MFs) on a mica substrate was reported by vapor phase deposition via a rapid cooling strategy. The screw dislocation-driven growth behavior is confirmed based on systematic characterizations. Our experimental results demonstrate that the stress induced during the rapid cooling process is critical for the controllable synthesis of γ-GeSe MFs and corresponding growth mechanism was proposed. Our work provides a new experimental strategy for the controlled growth of γ-GeSe MFs, which is beneficial for constructing GeSe-based nanoelectronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Quaternary III–V semiconductors are one of the most promising material classes in optoelectronics. The bandgap and its character, direct or indirect, are the most important fundamental properties determining the performance and characteristics of optoelectronic devices. Experimental approaches screening a large range of possible combinations of III- and V-elements with variations in composition and strain are impractical for every target application. We present a combination of accurate first-principles calculations and machine learning based approaches to predict the properties of the bandgap for quaternary III–V semiconductors. By learning bandgap magnitudes and their nature at density functional theory accuracy based solely on the composition and strain features of the materials as an input, we develop a computationally efficient yet highly accurate machine learning approach that can be applied to a large number of compositions and strain values. This allows for a computationally efficient prediction of a vast range of materials under different strains, offering the possibility of virtual screening of multinary III–V materials for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Self-powered photodetectors (PDs) with distinguishable wavelength detection have great application potential in intelligent optoelectronics. However, slow response speed, low responsivity, and signal interference prevent its development and applications. Here, an asymmetric bipolar p-NiO/n-ZnO/p-Si heterojunction is designed as a wavelength-distinguishable PD by using two tandem p–n junctions to reduce the wavelength interference and effectively separate photo-generated carriers. Bidirectional transient photocurrents are achieved in the external circuit for ultraviolet and visible detection by smartly using the pyro-phototronic effect induced by the variations of spontaneous polarization and interface-induced polarization within the p–n–p junction. The transient peak-to-peak current are thus significantly improved by 2310% for 325 nm lasing and by 5950% for 442 nm lasing. This approach can be used to realize wavelength-distinguishable detection through flexibly selecting materials and using the pyro-phototronic effect. The designed PD might have potential applications in the fields of environmental detection, smart imaging, and intelligent optoelectronics. [ABSTRACT FROM AUTHOR]

Phyllosilicate minerals are an emerging class of naturally occurring layered insulators with large bandgap energy that have gained attention from the scientific community. This class of lamellar materials has been recently explored at the ultrathin two-dimensional level due to their specific mechanical, electrical, magnetic, and optoelectronic properties, which are crucial for engineering novel devices (including heterostructures). Due to these properties, phyllosilicate minerals can be considered promising low-cost nanomaterials for future applications. In this Perspective article, we will present relevant features of these materials for their use in potential 2D-based electronic and optoelectronic applications, also discussing some of the major challenges in working with them. [ABSTRACT FROM AUTHOR]

PbS semiconductor nanocrystals (NCs) have been heavily explored for infrared optoelectronics but can exhibit visible-wavelength quantum-confined optical gaps when sufficiently small (⌀ = 1.8–2.7 nm). However, small PbS NCs traditionally exhibited very broad ensemble absorption linewidths, attributed to poor size-heterogeneity. Here, harnessing recent synthetic advances, we report photophysical measurements on PbS ensembles that span this underexplored size range. We observe that the smallest PbS NCs pervasively exhibit lower brightness and anomalously accelerated photoluminescence decays—relative to the idealized photophysical models that successfully describe larger NCs. We find that effects of residual ensemble size-heterogeneity are insufficient to explain our observations, so we explore plausible processes that are intrinsic to individual nanocrystals. Notably, the anomalous decay kinetics unfold, surprisingly, over hundreds-of-nanosecond timescales. These are poorly matched to effects of direct carrier trapping or fine-structure thermalization but are consistent with non-radiative recombination linked to a dynamic surface. Thus, the progressive enhancement of anomalous decay in the smallest particles supports predictions that the surface plays an outsized role in exciton–phonon coupling. We corroborate this claim by showing that the anomalous decay is significantly remedied by the installation of a rigidifying shell. Intriguingly, our measurements show that the anomalous aspect of these kinetics is insensitive to temperature between T = 298 and 77 K, offering important experimental constraint on possible mechanisms involving structural fluctuations. Thus, our findings identify and map the anomalous photoluminescence kinetics that become pervasive in the smallest PbS NCs and call for targeted experiments and theory to disentangle their origin. [ABSTRACT FROM AUTHOR]

Nanosheets of transition metal dichalcogenides with prospects of photocatalysis and optoelectronics applications have significant potential in device fabrication due to their low-cost production and easily controllable morphology. Here, non-degenerate pump-probe differential transmission studies with varying pump-fluence have been carried out on single-phase 2H–MoSe2 and mixed-phase 1T/2H–MoSe2 nanosheets to characterize their excited carrier dynamics. For both the samples, the differential probe transmission data show photo-induced bleaching at earlier pump-probe delay followed by photo-induced absorption unveiling signatures of exciton-state filling, exciton trapping, defect-mediated photo-induced probe absorption and recombination of defect bound excitons. The exciton trapping and photo-induced absorption by the trapped-carriers are estimated to occur with time constant of ∼430 to 500 fs based on multi-exponential modelling of the differential transmission till pump-probe delay of ∼3.5 ps. Biexponential modeling of the subsequent slow-recovery of the negative differential transmission at pump-probe delay ≳3.5 ps reveals that the exciton recombination happens via two distinct decay channels with ∼25 to 55 ps (τ1) and ≳1 ns (τ2) time constants. Pump-fluence dependent reduction in τ1 and further modelling of exciton population using higher order kinetic rate equation reveals that the two-body exciton-exciton annihilation governs the exciton recombination initially with a decay rate of ∼ 10 − 8 cm3s−1. The detailed analysis suggests that the fraction of total excitons that decay via long decay channel decreases with increasing exciton density for 2H–MoSe2, in contrast to 1T/2H–MoSe2 where the fraction of excitons decaying via long decay channel remains constant. [ABSTRACT FROM AUTHOR]

Preparing halide perovskite films by solvent-free, powder-based processing approaches currently attracts more and more attention. However, working solar cells employing dry, powder-based halide perovskite thin films, have not been demonstrated so far. Herein, perovskite solar cells are presented where the absorber layer is prepared by transferring readily synthesized perovskite powders into a compact thin film using a fully dry-powder-processing concept. Compact thin films are deposited via an optimized powder aerosol deposition (PAD) process. Pressing at 120 °C further improves the morphology and the optoelectronic film properties. Integrating the perovskite films in a solar cell configuration results in fully working devices, with champion power conversion efficiencies of >6%. While the (optoelectronic) properties of the PAD-processed films are found to be comparable with their solution-processed counterparts, investigations of the solar cell stack suggest deterioration of the electron-transport layer properties due to the PAD process, and the presence of hydrates at the perovskite surface to be important factors that contribute to the limited solar cell efficiency. Herein, perspectives to overcome the identified limitations are outlined, emphasizing the high potential and realizability of efficient perovskite solar cells based on dry-powder-processing approaches in the future.

Abstract The ability to modulate optical and electrical properties of two-dimensional (2D) semiconductors has sparked considerable interest in transition metal dichalcogenides (TMDs). Herein, we introduce a facile strategy for modulating optoelectronic properties of monolayer MoSe2 with external light. Photochromic diarylethene (DAE) molecules formed a 2-nm-thick uniform layer on MoSe2, switching between its closed- and open-form isomers under UV and visible irradiation, respectively. We have discovered that the closed DAE conformation under UV has its lowest unoccupied molecular orbital energy level lower than the conduction band minimum of MoSe2, which facilitates photoinduced charge separation at the hybrid interface and quenches photoluminescence (PL) from monolayer flakes. In contrast, open isomers under visible light prevent photoexcited electron transfer from MoSe2 to DAE, thus retaining PL emission properties. Alternating UV and visible light repeatedly show a dynamic modulation of optoelectronic signatures of MoSe2. Conductive atomic force microscopy and Kelvin probe force microscopy also reveal an increase in conductivity and work function of MoSe2/DAE with photoswitched closed-form DAE. These results may open new opportunities for designing new phototransistors and other 2D optoelectronic devices.

Using first-principles calculations, we have studied the structural and electronic properties of ZrOX (X = S, Se, and Te) monolayers and their van der Waals heterostructures in the tetragonal structure. Our results show that these monolayers are dynamically stable and are semiconductors with electronic bandgaps ranging from 1.98 to 3.16 eV as obtained with the GW approximation. By computing their band edges, we show that ZrOS and ZrOSe are of interest for water splitting applications. In addition, the van der Waals heterostructures formed by these monolayers show a type I band alignment for ZrOTe/ZrOSe and a type II alignment for the other two heterostructures, making them potential candidates for certain optoelectronic applications involving electron/hole separation. [ABSTRACT FROM AUTHOR]

The structural, optoelectronics, and transport properties of TlTaO3 compounds were determined utilizing the full potential augmented plane wave approach using first‐principle method. We have considered the generalized gradient approximation for structural optimization and modified Becke–Johnson for electronic properties. The electronic properties reveal that the studied TlTaO3 possesses direct bandgap of magnitude 1.52 eV. Between 0 and 12 eV, optical spectra calculations are made, taking into account the real and imaginary parts of the dielectric function, refractive index, and loss function. The transport properties are estimated considering Boltzmann transport theory. The Seebeck coefficient, electrical conductivity, thermal conductivity, and power factor are all assessed using the Boltzmann transport theory. The optimized thermoelectric response of the examined TlTaO3 is produced by the improved carrier mobility, which also improves the thermoelectric efficiency of the TlTaO3. The obtained results will act as a theoretical road map for upcoming experimental and commercial TlTaO3 applications. [ABSTRACT FROM AUTHOR]

All-inorganic perovskites have garnered significant attention in optoelectronics. Herein, square CsPb2Br5 nanosheets, with lateral dimensions of up to 200 μm and a thickness of less than 50 nm, were successfully synthesized via a straightforward aqueous method using HBr as a morphology-tailoring agent. A photodetector composed of a single nanosheet was subsequently fabricated and exhibited remarkable photodetection capabilities, demonstrating a detectivity of 5.98 × 109 Jones. These findings offer new perspectives on the synthesis and utilization of CsPb2Br5 and other perovskite nanostructures in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Recent optoelectronics domain studies concluded the increased need to provide improved, stable, and efficient designs to operate high-power NIR (Near-infrared) laser diodes. The existing current regulators provide either stability or high efficiency, with the actual studied design representing a solution providing both advantages in a complex constant current driver. Therefore, this study covers the LTI (Linear Time-Invariant) analysis of a cascade feedback loop current regulator, aiming to achieve a constant current through a high transconductance load. Furthermore, this analysis also refers to such transconductance loads as NIR laser diode bars, having their emission spectrum closely matching one major absorption band of Nd:YAG (Neodymium-dopped Yttrium Aluminum Garnet) solid-state lasers, potentially providing an increased-stability solution to high power, continuous wave side-pumped applications, as well as various DPSS (Diode-Pumped Solid-State) laser prototypes. This design is a suitable solution for an infinite transconductance load, allowing the indefinite power increase in either direct diode or pumped laser applications while maintaining adequate stability. However, as it will be covered, multiple constraints occur for this hardware design. [ABSTRACT FROM AUTHOR]

Chalcogenide composites, a category of non-oxide glasses, have shown great potential in various applications such as optoelectronics, thermal imaging, memory-switching devices, lasers, and more. Owing to the distinctive physical properties inherent in chalcogenide glasses, these materials have garnered significant interest across various technological domains. This study aims to analyze the impact of incorporating sulfur (S) and antimony (Sb) into (S3Sb2)x(S2Ge)100−x:x = 10, 20, 30 chalcogenide composites, assessing their radiation shielding, structural, physical, and electrical properties. Three distinct composites, designated as SSbGe-10, SSbGe-20, and SSbGe-30, are irradiated with gamma photons across an energy range of 0 to 15 MeV. The assessment of the radiation shielding attributes is conducted through the utilization of the FLUKA Monte Carlo (MC) Code. Phillips and Thorpe's theory is employed to analytically estimate structural and physical attributes such as Coordination Number (CN), bond-bending constraints (NS), bond-stretching constraints (NC), constraints Number (Ncons), Floppy mode (F), and stoichiometry (R). The electrical features of the provided specimens are analyzed through the utilization of the effective electron conductivity (Ceff), as ascertained by the Phy-X: PSD software. The findings indicate that the augmentation of the x value within the range of 10–30 wt.% positively augments the gamma photon shielding efficacy of the composite materials. Both NS and NC demonstrate diminishing patterns, encompassing the range of 2.64 to 2.575 and 7.56 to 7.30, respectively. Additionally, the stoichiometry (R > 1) for the investigated samples indicates that the chosen glasses are rich chalcogenide composites. The exhaustive examination of the physical, radiation shielding, and electrical characteristics of the prepared chalcogenide glasses provides valuable insights for subsequent investigations into various chalcogenide glass formulations. [ABSTRACT FROM AUTHOR]

Herein, a lead-free double perovskite is synthesized utilizing an antisolvent recrystallization technique. The double perovskite Na 2 AgBiBr 6 is studied in detail, including its crystal structure, stability, morphology, electronic, optical, and thermoelectric properties. X-ray diffraction (XRD) confirms the formation of Na 2 AgBiBr 6 double perovskite and demonstrates remarkable structural stability. Crystals of uniform multifaceted Na 2 AgBiBr 6 are seen by scanning electron microscopy (SEM). Polycrystalline-Na 2 AgBiBr 6 crystals in a cubic ordered phase by the solution synthesis approach are ensured by TEM and electron diffraction analysis. Furthermore, energy-dispersive X-ray spectroscopy (EDX) mapping indicates the overlapping of Na, Ag, Bi, and Br elements and the uniform content of each element in the synthesized material. According to UV–vis spectroscopy, a band gap of 2.6 eV is observed. Further, the density functional theory (DFT) calculations suggested the structural as well as thermal stability acquired by tolerance factor and negative formation energy, respectively. DFT-predicted lattice parameter and band gap are verified by XRD and UV–vis spectroscopy, respectively. Elastic properties confirmed the mechanical stability, anisotropy, and ductile nature. The optical properties revealed the higher absorbance and low reflectivity in the energy range 0–6 eV. The thermoelectric attributes ensure the higher electrical conductivity and low thermal conductivity resulting in a figure of merit (ZT) value of 0.77. The outcomes of this research propose that the lead-free and eco-friendly Na 2 AgBiBr 6 double perovskite holds considerable potential as absorber layer material for solar cells and for thermoelectric device applications. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) self‐powered photodetectors have attracted considerable attention due to their exceptional sensitivity, and low dark current. However, the poor responsivity of single heterojunctions with type‐III band alignment is primarily attributed to band‐to‐band tunneling. The implementation of a double heterojunction has the potential to enhance photovoltaic responsivity, enable broadband detection, and improve response speed. In this study, a back‐to‐back type‐III band alignment based on SnSe2/Bi2Se3/MoTe2 double heterostructure by dry transfer method is designed. As a result, it exhibited an impressive photovoltaic performance in the overlapping region. Achieving a maximum responsivity (R), external quantum efficiency (EQE), photoelectric conversion efficiency (PCE), and specific detectiviy (D*) of 493 mA W−1, 76 %, 3 % and 1.8 × 1011 Jones at a gate voltage (Vg) of 60 V under 808 nm illumination. It can be ascribed to the effective depletion region at the SnSe2/Bi2Se3 interface and the reversed band edge from depletion to accumulation mode at Bi2Se3/MoTe2 interface. In addition, a faster response speed of 553/583 µs and a lower dark current of 2.9 pA can be obtained. Moreover, this double heterostructure achieves better photovoltaic performance with Vg compared to the single MoTe2/SnSe2 heterojunction. These results demonstrates the potential as a candidate for back‐to‐back type‐III band alignment in low power optoelectronics. [ABSTRACT FROM AUTHOR]

This study investigates into the synthesis, characterization, and multifaceted analysis of a composite material comprised of copper vanadium oxide (CVO) and graphitic Carbon Nitride g-C 3 N 4 (GCN). The fabrication of the composite was achieved through wet-chemical method followed by annealing at 600 °C for 3 h, ensuring controlled composition and structure. The characterization process encompassed X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–visible spectroscopy, unveiling the composite's crystalline structure, novel nano-rod morphology with decorated flakes, and UV–visible light activation capability. The obtained band gap of approximately 2.7 eV signified the composite's optical properties. Electrochemical analysis, including cyclic voltammetry (CV), highlighted the composite's robust biosensing attributes, particularly in response to ascorbic acid. The conducting and metallic characteristics of the composite enhanced its reactivity, promising applications in biosensors and energy storage devices. This comprehensive investigation elucidates the multifaceted potential of the CVO/GCN nano-composite across diverse optoelectronic realms. [ABSTRACT FROM AUTHOR]

A synthesis and characterization of luminescent nano‐heterostructures consisting of CdSe nanorod (NR) cores and a ZnO shell with up to three monolayers of ZnO is reported. The core/shell heterostructures show a tunable, dual photoluminescence (PL) in visible and Near Infrared (NIR) spectral ranges. Upon shelling the visible PL band attributed to the carrier recombination within the CdSe core shifts to lower energy by ≈0.05 to 0.15 eV relative to the bare CdSe NRs, due to a reduced quantum confinement. A NIR band, observed ≈0.4 – 0.5 eV below the PL energy of the CdSe core, is attributed to a type‐II carrier recombination across the CdSe/ZnO interface. The total PL quantum yield (PLQY) in the brightest heterostructures reaches ≈20%, increasing ≈100‐fold over the PLQY of the corresponding bare CdSe NRs. The average lifetimes of the visible PL in some heterostructures exceeds 100 ns, compared to ≈5 ns lifetime typical for bare CdSe NRs. The average PL lifetimes attributed to the type‐II charge separated states exceed one microsecond. Strong NIR PL, tunable in the 800–900 nm spectral range and the long‐lived charge separated state make the CdSe/ZnO core‐shell NRs appealing materials for exploitation in applications such as bioimaging, photocatalysis and optoelectronics. [ABSTRACT FROM AUTHOR]

Emerging nano-kirigami/origami technology enables the flexible transformations of 2D planar patterns into exquisite 3D structures in situ and has aroused great interest in the areas of nanophotonics and optoelectronics. This paper briefly reviews some milestone research and breakthrough progresses in nano-kirigami/origami from the aspects of stimuli approaches and application directions. Versatile stimuli for kirigami/origami, including capillary force, residual stress, mechanical force, and irradiation-induced stress, are introduced in the micro/nanoscale region. Appealing optical applications and reconfigurable schemes of nano-kirigami/origami structures are summarized, offering effective routes to realize tunable nanophotonic and optoelectronic devices. Future challenges and promising pathways are also envisioned, including design methods, innovative materials, multi-physics field driving, and reprogrammable devices. [ABSTRACT FROM AUTHOR]

Solid‐state hybrid materials with designability in topology and tunable photo‐responsiveness hold great promise for multitudinous applications from optoelectronics to information storage/communication. However, the judicious design and synthesis of metal–organic frameworks (MOFs) with intrinsically custom‐made nonlinear optical (NLO) properties including multiple photon absorption and harmonic generation effects suitable for miniaturized devices remain highly challenging. Herein, the design and synthesis of a novel pillared framework named after Zn‐TCPE‐DPNI MOF coordinated by zinc ions (Zn2+), aggregation induced emission (AIE) featured [1,1′‐biphenyl]‐4‐carboxylic acid (H4TCPE), and N,N′‐di(4‐pyridyl)‐1,4,5,8‐naphthalenetetracarboxydiimide (DPNI) are reported. The highly ordered Zn‐TCPE‐DPNI MOF single crystal exhibits tunable NLO responses by switching incident excitation wavelengths of a femtosecond laser from 900 to 1500 nm. The noticeable transformation from two‐ or three‐photon excited photoluminescence (2PL or 3PL) to the concurrent occurrence of 3PL and third harmonic generation (THG), and eventually to the mere emergence of THG with a high effective susceptibility χ(3) (3ω) of 2.9 × 10−12 esu is observed. This study paves a novel avenue for the design and synthesis of photoluminescent MOF crystals with tunable NLO responses toward the fabrication of multifunctional NLO devices targeted for optoelectronics and information communication. [ABSTRACT FROM AUTHOR]

Efficient characterization of optoelectronic material properties represents a crucial step in the development of next‐generation infrared (IR) materials and devices. For the first time, a sensitive, contact‐free optoelectronic material characterization platform is demonstrated that exploits the unique properties of radio frequency (RF) topological edge states implemented in a topological microstrip waveguide. The topological device is compatible with standard printed circuit board (PCB) processes with no additional materials, stubs, or resonators. The waveguide and topological properties computationally are designed and then experimentally the results are validated with S‐parameter and near‐field measurements. Finally, as a proof of principle, the room temperature spectral response of a micron‐scale thick mid‐wave infrared (MWIR) mercury cadmium telluride (Hg0.70Cd0.30Te) is measured using the topological microstrip and a five‐fold and 20‐fold increase is demonstrated in response when compared to a plain microstrip and trivial bandgap device, respectively. These results open the door to straightforward, low‐cost characterization of optoelectronic films. [ABSTRACT FROM AUTHOR]

In this paper, optical and transport properties of Polyvinyl Alcohol/Silver incorporated Zinc Oxide (PVA/Ag–ZnO) nanocomposites of varying Ag–ZnO nanoparticles content prepared by solution casting method are studied to explore their multifunctional applications. The nanocomposites are characterized using X-ray diffraction, Scanning electron microscope, Energy-dispersive X-ray analysis, UV–Visible spectroscopy and Fourier transform infra-red spectroscopy. The UV–visible spectra showed zero transmittance in the UV region with increasing Ag–ZnO nanoparticles content in the PVA matrix suggesting that the nanocomposites could be used as a potential UV shielding material. The optical band gap energy decreases from 5.77 to 1.54 eV with increasing Ag–ZnO nanoparticles content in the PVA matrix. Frequency- and temperature-dependent dielectric measurement of the samples reveals maximum dielectric constant at PVA/15 wt% Ag–ZnO nanocomposite. Dielectric loss results showed a lossless behaviour at higher frequencies (< 0.2), suggesting that the prepared samples are suitable for use in high-frequency applications. The AC conductivity studies reveal that electrical conduction mechanism in the nanocomposites is governed by the correlated barrier hopping mechanism. Activation energy calculation indicates the involvement of two different types of conduction mechanism in the samples. The Nyquist plot for all the samples is fitted using the equivalent circuit model. The studied results show that the PVA/Ag–ZnO nanocomposites can serve as potential candidates for optoelectronic and electronic device application. [ABSTRACT FROM AUTHOR]

The electronic, optoelectronic, linear and nonlinear optical (NLO) properties of some corannulenes of formula C5n2H5n (with n = [2,4]), doped with boron–nitride units at the rim position, have been studied using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. This work aims to substitute B–N units at the rim position in some corannulene structures in order to propose new materials for electronic, optoelectronic and nonlinear optical applications. According to the investigations carried out, the analysis of the cohesive energies of the studied corannulene derivatives indicates that they are energetically stable materials. Based on the |HOMO–LUMO| energy gap values, we find that corannulenes doped with B–N units at the rim position exhibit the same semiconducting nature as the parent structure from which they derive. Moreover, the value of first-order hyperpolarizability (β0) of structures containing B–N isoelectronic units at the rim position in corannulenes is higher than that of the urea molecule considered as a reference molecule commonly used in nonlinear optics (NLO). We hope that the present work will also pave the way for the design of high-performance nonlinear optical materials based on boron–nitride-doped corannulene at the rim position. TD/B3LYP-D3/6–31 + G(d) calculations revealed that among the proposed derivatives, the compounds C35B5N5H15 and C70B5N5H20 exhibit high photo-current response in the visible range. This gives these new materials good performances for optoelectronic applications. Although all the studied properties of the doped structures with B–N units at the rim position are not better than those at the spoke position reported in the literature, these proposed systems have good capabilities to be used as suitable organic semiconductors in the photovoltaic field. [ABSTRACT FROM AUTHOR]

All-solution-processed organic optoelectronic devices can enable the large-scale manufacture of ultrathin wearable electronics with integrated diverse functions. However, the complex multilayer-stacking device structure of organic optoelectronics poses challenges for scalable production. Here, we establish all-solution processes to fabricate a wearable, self-powered photoplethysmogram (PPG) sensor. We achieve comparable performance and improved stability compared to complex reference devices with evaporated electrodes by using a trilayer device structure applicable to organic photovoltaics, photodetectors, and light-emitting diodes. The PPG sensor array based on all-solution-processed organic light-emitting diodes and photodetectors can be fabricated on a large-area ultrathin substrate to achieve long storage stability. We integrate it with a large-area, all-solution-processed organic solar module to realize a self-powered health monitoring system. We fabricate high-throughput wearable electronic devices with complex functions on large-area ultrathin substrates based on organic optoelectronics. Our findings can advance the high-throughput manufacture of ultrathin electronic devices integrating complex functions. [ABSTRACT FROM AUTHOR]

In contrast to conventional atomic crystals, two‐dimensional inorganic molecular crystals (2DIMCs) possess a unique crystal structure composed of small molecules held together by van der Waals force. Such distinctive structure grants them specific chemical and physical properties highly suitable for electronic and optoelectronic applications. However, the synthesis of 2DIMCs has posed significant challenges due to the inherent issues such as uncontrollable growth orientation stemming from their natural crystalline isotropy and poor stability resulting from the weak intermolecular connections. Addressing these obstacles, the preparation of large‐scale and highly‐stable 2DIMC BiBr3, and its heterostructure are reported here by developing crystallization orientation engineering strategies. This approach has successfully yielded centimeter‐scale 2DIMC BiBr3 with a clean and dense surface, showcasing exceptional long‐term air‐stability exceeding 80 days. Furthermore, the universal growth of large‐scale 2DIMC BiBr3 is demonstrated on diverse substrates, including SiO2, Al2O3, and MoS2 monolayers. Notably, the resultant 2D BiBr3/MoS2 heterostructure exhibits remarkable photoluminescence enhancement. This contribution paves a universal avenue for the mature synthesis of large‐scale 2DIMCs with superior stability, holding great promise for prompting their integration in practical electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Solution‐processed low‐bandgap semiconductors are crucial to next‐generation infrared (IR) detection for various applications, such as autonomous driving, virtual reality, recognitions, and quantum communications. In particular, III–V group colloidal quantum dots (CQDs) are interesting as nontoxic bandgap‐tunable materials and suitable for IR absorbers; however, the device performance is still lower than that of Pb‐based devices. Herein, a universal surface‐passivation method of InAs CQDs enabled by intermediate phase transfer (IPT), a preliminary process that exchanges native ligands with aromatic ligands on the CQD surface is presented. IPT yields highly stable CQD ink. In particular, desirable surface ligands with various reactivities can be obtained by dispersing them in green solvents. Furthermore, CQD near‐infrared (NIR) photodetectors are demonstrated using solution processes. Careful surface ligand control via IPT is revealed that enables the modulation of surface‐mediated photomultiplication, resulting in a notable gain control up to ≈10 with a fast rise/fall response time (≈12/36 ns). Considering the figure of merit (FOM), EQE versus response time (or −3 dB bandwidth), the optimal CQD photodiode yields one of the highest FOMs among all previously reported solution‐processed nontoxic semiconductors comprising organics, perovskites, and CQDs in the NIR wavelength range. [ABSTRACT FROM AUTHOR]

One hindrance in transparent electronics is the lack of high‐performance p‐type transparent conductors (TCs). The state‐of‐the‐art p‐type TC, CuI, has a conductivity two orders of magnitude lower than n‐type TCs like ITO. While doping strategies have shown promise in enhancing the hole carrier density in CuI, they often come at the expense of hole mobility. Therefore, understanding how extrinsic dopants affect the mobility of CuI is critical to further improve the performance of CuI‐based TCs. Here the structural and electronic properties of Cs‐doped CuI are investigated. It is demonstrated that ≈4 at.% Cs doping in CuI increases the carrier density from 2.1 × 1019 to 3.8 × 1020 cm−3 while preserving the film microstructure and local coordination of Cu, as confirmed by HRTEM and XAS analysis. Introducing S as a co‐dopant in Cs:CuI boosts the carrier density to 8.2 × 1020 cm−3, reaching a stable conductivity of ≈450 S cm−1. In all cases, the enhanced carrier density negatively affects the hole mobility with ionized impurity scattering and increased Seebeck hole effective mass as mobility limiting mechanisms. Nonetheless, the new Cs, S co‐doped CuI exhibits high p‐type conductivity, Vis–NIR transparency, and stability, presenting an attractive candidate for future transparent electronic devices. [ABSTRACT FROM AUTHOR]

The work reported here deals with fabricating iron oxide nanoparticles incorporated polyvinyl alcohol nanocomposite films via the solution‐casting green route, characterized using various characterization techniques. X‐ray diffraction analysis shows interaction of nanoparticles with the polyvinyl alcohol matrix, scanning electron microscopy shows surface morphology of crack‐free films, energy dispersive spectroscopy indicates elemental purity, tensiometer analysis shows changing behavior of hydrophilic to hydrophobic, thermogravimetric analysis shows improved thermal stability, ultraviolet‐visible spectroscopy shows tunable optical properties, and frequency response analysis shows improved electrical properties. A small incorporation (1 wt. %) of iron oxide nanoparticles has induced significant alternations in structural, wetting, thermal, optical, and electrical properties of the polyvinyl alcohol‐based nanocomposite films. Results showed notable changes in the structural phases, water contact angle (39.5° to 97.7°), optical absorption edge (5.12 eV to 4.84 eV), indirect band gap (4.99 eV to 4.68 eV), direct bandgap (5.41 eV to 5.21 eV), and band tail (0.57 eV to 0.89 eV) from native polyvinyl alcohol to polyvinyl alcohol/iron oxide nanocomposite films. Enhancements were observed in refractive indices, optical conductivity, optical dielectric loss, thermal stability, dielectric constant, and dielectric loss on incorporating iron oxide nanoparticles into the polyvinyl alcohol matrix. The fabricated nanocomposite films might be a potential material for optoelectronic and microelectronics applications. [ABSTRACT FROM AUTHOR]

Silver (Ag) nanowires, as an important one-dimensional (1D) nanomaterial, have garnered wide attention, owing to their applications in electronics, optoelectronics, sensors, and other fields. In this study, an alternative hydrothermal route was developed to synthesize Ag nanowires via modified reduction of Ag+. Silver sulfamate plays an important role in the formation of Ag nanowires via controlled release of free Ag+. Results of controlled experiments and characterizations such as UV–vis spectroscopy, FTIR, XPS, and 1H NMR revealed that sulfamic acid does not function as a reductant, supporting by the generation of free Ag+ instead of Ag nanostructures in hydrothermally treated silver sulfamate solution. The initial reduction of Ag+ was induced by the combination of poly (vinylpyrrolidone) (PVP) end group and degradation products. This phenomenon was supported by abundant free Ag+ in the mixed preheated silver sulfamatic and preheated PVP aqueous solutions, indicating a second and distinct Ag+ autocatalytic reduction. Thus, the roles of different reagents and Ag+ reduction must be studied for nanomaterial syntheses. [ABSTRACT FROM AUTHOR]

The present work explores the significance of charge transfer band (CTB) excitation, with large absorption capacity, of Pr3+ doped Sr 3 LiSbO 6 phosphor materials for bluish-green emission. Phosphor materials were synthesized via the conventional high-temperature solid-state method. The formation of phase structure was confirmed by XRD. The structural parameter was estimated from Rietveld refinement. Field emission scanning electron microscopy (FESEM) and High-resolution transmission electron microscopy (HRTEM) coupled with mapping and EDX spectroscopy were employed to get high-resolution images of morphologic structure. Raman and FTIR spectra were investigated to detect the presence of different vibrational levels and functional groups respectively. The elemental compositions were further confirmed via XPS survey scan spectrum and their oxidation state was also explored. The optical band-gap was found to increase first with doping concentration and then start to decrease after doping of 2 mol%, this result was further supported by photoluminescence (PL) emission spectra. PL emission spectra presented the characteristic peaks of Pr3+ due to f-f transitions. PL emission spectra illustrated that the concentration quenching took place at 2 mol% doping of Pr3+, which was governed by dipole-dipole coupling. The decay curves of each sample were recorded for specific excitation and emission wavelengths of 262 nm and 490 nm respectively. All the decay curves were well-fitted with single exponential function. The observed average decay time was 10.5 μs. Afterward, photometric studies including Chromaticity International d'Eclairage (CIE), correlated color temperature (CCT) and color purity (CP) were performed. Calculated CIE values were found to lie in bluish-green regions with lower CP and higher CCT. These results obtained from various characterizations conclude that the proposed Sr 3 LiSbO 6 phosphor, doped with various concentrations of Pr3+ (0 mol% to 7 mol% of Pr3+), reveal their applicability in the field of solid-state lighting for white light emitting diodes. [ABSTRACT FROM AUTHOR]

The ability to modulate optical and electrical properties of two-dimensional (2D) semiconductors has sparked considerable interest in transition metal dichalcogenides (TMDs). Herein, we introduce a facile strategy for modulating optoelectronic properties of monolayer MoSe2 with external light. Photochromic diarylethene (DAE) molecules formed a 2-nm-thick uniform layer on MoSe2, switching between its closed- and open-form isomers under UV and visible irradiation, respectively. We have discovered that the closed DAE conformation under UV has its lowest unoccupied molecular orbital energy level lower than the conduction band minimum of MoSe2, which facilitates photoinduced charge separation at the hybrid interface and quenches photoluminescence (PL) from monolayer flakes. In contrast, open isomers under visible light prevent photoexcited electron transfer from MoSe2 to DAE, thus retaining PL emission properties. Alternating UV and visible light repeatedly show a dynamic modulation of optoelectronic signatures of MoSe2. Conductive atomic force microscopy and Kelvin probe force microscopy also reveal an increase in conductivity and work function of MoSe2/DAE with photoswitched closed-form DAE. These results may open new opportunities for designing new phototransistors and other 2D optoelectronic devices. [ABSTRACT FROM AUTHOR]

Grating couplers that interconnect photonic chips to off-chip components are crucial for various optoelectronics applications. Despite numerous efforts in past decades, the existing grating couplers are still far from optimal in energy efficiency and thus hinder photonic integration toward a larger scale. Here, we propose a strategy to achieve ultralow-loss grating couplers by using unidirectional guided resonances (UGRs), suppressing the useless downward radiation with no mirror on the bottom. By engineering the dispersion and apodizing the geometry of grating, we experimentally realize a grating coupler with a record-low loss of -0.34 dB and 1-dB bandwidth exceeding 30 nm at the telecom wavelength of 1550 nm and further demonstrate an optic via with a loss of only -0.94 dB. Given that UGRs ubiquitously exist in a variety of grating geometries, our work sheds light on a systematic method to achieve energy-efficient optical interconnect and paves the way to large-scale photonic integration. [ABSTRACT FROM AUTHOR]

Marrying nanostructures with thin films is a recent trend in flexible optoelectronics to improve light trapping and mechanical stability. Radial junction (RJ) a‐Si:H thin film optoelectronics, directly deposited upon the vapor‐liquid‐solid (VLS) grown silicon nanowires (SiNWs), can pave the way to achieving excellent flexibility and a high power‐to‐weight ratio (PTWR). Thanks to their vertical‐standing geometry, SiNWs framework can enhance the mechanical stability of RJ units, by keeping the working region far away from the stress‐rich substrate surface. Using low‐melting‐point metals as catalysts, the SiNW array can be fabricated at a low temperature down to 350 °C in a PECVD system, making it possible to directly construct robust RJ units on flexible, low‐cost substrates, such as Al foil. In this review, the recent progress of the flexible RJ a‐Si:H thin film solar cells/photodetectors that are directly fabricated on the surface of low‐cost flexible substrates is reviewed. Moreover, these RJ flexible optoelectronics are demonstrated for use in wearable and real‐time health monitoring, and as cardiac pacemakers for heart stimulation. This RJ technology highlights a promising potential to establish high‐performance, low‐cost, mechanically stable flexible optoelectronic for wearable, portable applications. [ABSTRACT FROM AUTHOR]

The emergence of novel topological semimetal materials, accompanied by exotic non‐equilibrium properties, not only provides a fertile playground for a fundamental level of interest but also opens exciting opportunities for inventing new applications by making use of different light‐induced effects such as nonlinear optics, optoelectronics, especially for the highly pursued terahertz (THz) technology due to the gapless electronic structures. Exploring type‐II Weyl semimetal endowed with the richness of quantum wavefunction and peculiar band structure, underlie strong nonlinear coupling with THz waves. Here, the selective growth of type‐II Weyl semimetal NbIrTe4 by means of a self‐flux approach is reported, which hosts strongly tilted Weyl cones and exotic Fermi arcs. The oscillating THz field induced by the antenna is engineered in terms of planar metal‐topological semimetal‐metal structure, along with van der Waals stacking, which allows for self‐powered photodetection at room temperature. The results elucidate the superior performance of NbIrTe4‐graphene heterostructure‐based photodetectors with responsivity up to 264.6 V W−1 at 0.30 THz, fast response of 1 µs as well as low noise equivalent power ˂0.28 nW Hz−0.5 is achieved, already exhibiting high‐quality imaging at THz frequency. The results promise superb impacts in exploring topological Weyl semimetals for efficient low‐energy photon harvesting. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) material photodetectors have gained great attention as potential elements for optoelectronic applications. However, the linearity of the photoresponse is often compromised by the carrier interaction, even in 2D photodiodes. In this study, a new device concept of dual‐floating van der Waals heterostructures (vdWHs) photodiode is presented by employing ambipolar MoTe2 and n‐type MoS2 2D semiconductors. The presence of type II heterojunctions on both sides of channel layers effectively depletes carriers and restricts the photocarrier trapping within the channel layers. As a result, the device exhibits robust linear photoresponse under photovoltaic mode from the visible (405 nm) to near‐infrared (1600 nm) band. With the built‐in electric field of the vdWHs, a linear dynamic range of ≈100 dB, responsivity of ≈1.57 A W−1, detectivity of ≈4.28 × 1011 Jones, and response speed of ≈30 µs are achieved. The results showcase a promising device concept with excellent linearity toward fast and low‐loss detection, high‐resolution imaging, and logic optoelectronics. [ABSTRACT FROM AUTHOR]

Conventional methods for pathogen detection in water rely on time-consuming enrichment steps followed by biochemical identification strategies, which require assay times ranging from 24 hours to a week. However, in recent years, significant efforts have been made to develop biosensing technologies enabling rapid and close-to-real-time detection of waterborne pathogens. In previous studies, we developed a plastic optical fiber (POF) immunosensor using an optoelectronic configuration consisting of a U-Shape probe connected to an LED and a photodetector. Bacterial detection was evaluated with the immunosensor immersed in a bacterial suspension in water with a known concentration. Here, we report on the sensitivity of a new optoelectronic configuration consisting of two POF U-shaped probes, one as the reference and the other as the immunosensor, for the detection of Escherichia coli. In addition, another methos of detection was tested where the sensors were calibrated in the air, before being immersed in a bacterial suspension and then read in the air. This modification improved sensor sensitivity and resulted in a faster detection time. After the immunocapture, the sensors were DAPI-stained and submitted to confocal microscopy. The histograms obtained confirmed that the responses of the immunosensors were due to the bacteria. This new sensor detected the presence of E. coli at 104 CFU/mL in less than 20 min. Currently, sub-20 min is faster than previous studies using fiber-optic based biosensors. We report on an inexpensive and faster detection technology when compared with conventional methods. [ABSTRACT FROM AUTHOR]

Optoelectronic devices, such as light‐emitting diodes, have been demonstrated as one of the most demanded forthcoming display and lighting technologies because of their low cost, low power consumption, high brightness, and high contrast. The improvement of device performance relies on advances in precisely designing novelty functional materials, including light‐emitting materials, hosts, hole/electron transport materials, and yet which is a time‐consuming, laborious and resource‐intensive task. Recently, machine learning (ML) has shown great prospects to accelerate material discovery and property enhancement. This review will summarize the workflow of ML in optoelectronic materials discovery, including data collection, feature engineering, model selection, model evaluation and model application. We highlight multiple recent applications of machine‐learned potentials in various optoelectronic functional materials, ranging from semiconductor quantum dots (QDs) or perovskite QDs, organic molecules to carbon‐based nanomaterials. We furthermore discuss the current challenges to fully realize the potential of ML‐assisted materials design for optoelectronics applications. It is anticipated that this review will provide critical insights to inspire new exciting discoveries on ML‐guided of high‐performance optoelectronic devices with a combined effort from different disciplines. [ABSTRACT FROM AUTHOR]

In this concept, we showcase the upsurge in the studies of dynamic ultralong room‐temperature phosphorescence (RTP) materials containing inorganic and/or organic components as versatile photo‐responsive platforms. The goal is to provide a comprehensive analysis of photo‐controllable RTP, and meanwhile delve into the underlying RTP properties of various classes of photochromic materials including metal‐organic complexes, organic‐inorganic co‐crystals, purely organic small molecules and organic polymers. In particular, the design principles governing the integration of the photochromic and RTP moieties within a single material system, and the tuning of dynamic RTP in response to light are emphasized. As such, this concept sheds light on the challenges and opportunities of using these tunable RTP materials for potential applications in optoelectronics, particularly highlighting their use of reversible information encryption, erasable light printing and rewritable smart paper. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) with high porosity have garnered considerable interest for various applications owing to their robust and customizable structure. However, conventional COFs are hindered by their narrow pore size, which poses limitations for applications such as heterogeneous catalysis and guest delivery that typically involve large molecules. The development of hierarchically porous COF (HP‐COF), featuring a multi‐scale aperture distribution, offers a promising solution by significantly enhancing the diffusion capacity and mass transfer for larger molecules. This review focuses on the recent advances in the synthesis strategies of HP‐COF materials, including topological structure design, in‐situ templating, monolithic COF synthesis, defect engineering, and crystalline self‐transformation. The specific operational principles and affecting factors in the synthesis process are summarized and discussed, along with the applications of HP‐COFs in heterogeneous catalysis, toxic component treatment, optoelectronics, and the biomedical field. Overall, this review builds a bridge to understand HP‐COFs and provides guidance for further development of them on synthesis strategies and applications. [ABSTRACT FROM AUTHOR]

Mode selecting plays a vital role in the field of optoelectronics, such as optical communication, signal processing, on-chip light manipulation, mode conversion, and frequency synthesis. In this work, flexible selection and enhancement of the frequency modes in an unidirectional coupled Su–Schrieffer–Heeger (SSH) frequency lattice are obtained with Floquet exceptional points (EPs) and chiral Zener tunneling (ZT). The unidirectional coupled non-Hermitian SSH frequency lattices are synthesized by a double-ring system with complex dynamical modulations. Under an effective direct current (dc) force induced by the phase-mismatching of the modulations, the two Floquet bands of the non-Hermitian frequency lattices are degenerated and the Floquet EPs arise. Therefore, the unidirectional and irreversible frequency mode conversion takes place, which is the chiral ZT. Moreover, through perturbation analysis and numerical simulations, we prove that the frequency modes of the two-band system can be selected and enhanced by a multi-photon resonance dc force. [ABSTRACT FROM AUTHOR]

III–V Indium Arsenide (InAs) nanowire photodetectors have attracted intensive research attention due to their high carrier mobility, direct and narrow bandgap, and nanoscale dimensions, offering immense potential in nanoscale optoelectronics, particularly for applications in photonic integrated circuits. Despite extensive studies on the properties of InAs nanowires, their photoresponse remains intricate, displaying bipolar behavior (i.e., positive and negative photoresponse) within the same device under varying conditions. However, the underlying driving mechanism remains unclear. In this work, we have systematically studied the transition between the negative photoresponse and positive photoresponse in the InAs nanowire photodetector under different conditions. We found the bipolar photoresponse is directly related to the occupation status of the surface trap states, and it could be effectively regulated by the gate voltage, power intensity, as well as the illumination duration. Furthermore, we developed a waveguide-integrated InAs nanowire photodetector using electron photoresist with an optical loss as low as 0.122 dB/μm. This achievement underscores its potential for application in photonic integrated photodetectors, laying the groundwork for future integration of InAs nanowire photodetectors into photonic integrated circuits. [ABSTRACT FROM AUTHOR]

Polybenzocoumarins, characterized by unique structural features, have emerged as a promising class of compounds with diverse applications. In the realm of fluorescence, these molecules exhibit notable properties attributed to their extended π‐conjugation, aromaticity, and potential for intramolecular charge transfer. Diverse synthetic methodologies, including green chemistry approaches and transition‐metal‐catalyzed reactions, are discussed. The review explores the impact of structural modifications on fluorescence behavior, providing insights for designing fluorescent probes. The versatility of polybenzocoumarins makes them promising in bioimaging, sensors, and optoelectronics. This concise overview serves as a valuable resource for researchers interested in the dynamic field of polybenzocoumarin chemistry. [ABSTRACT FROM AUTHOR]

Pyrene‐based molecules are being explored as prospective fullerene‐free acceptors for organic solar cells (OSCs), due to their easy accessibility, structural planarity, and excellent electron delocalization. In this work, we successfully designed and analyzed pyrene‐based acceptor materials (QL1–QL8) to investigate their photophysical and electro‐optical parameters. Various geometric parameters were computed at the MPW1PW91/6‐31G(d,p). Advanced quantum chemical approaches were employed to characterize the molecules. All the tailored molecules (QL1–QL8) exhibit a lower bandgap than the reference (R), signifying their superiority. Among these, QL8 was found to have a maximum absorption (λmax) at 791.37 nm and an optical bandgap (ELUMO − EHOMO) minimum of 2.11 eV. Redshifted absorption spectra are observed in both gaseous and solvent phases for all the designed (QL1–QL8) molecules in contrast to R. Among these, QL4 exhibits the highest light harvesting efficiency (0.9826), and open‐circuit voltage. A detailed donor–acceptor investigation of QL8/PBDB‐T revealed the marvelous charge switching at the donor–acceptor interface. The approach used in this study is anticipated to facilitate the manufacturing of highly efficient OSC molecules. [ABSTRACT FROM AUTHOR]

This work elucidates the impact of strain on the optical and electronic properties of Fe-doped lithium niobate using density functional theory. The Fe-doped lithium niobate is applied with the tensile and compressive strain (10% and 20%) and optical properties are analyzed. Lithium niobate, a large bandgap material (bandgap 3.56 eV), has absorption limited to the UV region of the optical spectrum only. For the Fe-doped lithium niobate, the bandgap is 1.38 eV, with low absorption in the visible region. The computed results show that the tensile and compressive strains have significantly narrowed down the bandgap of Fe-doped lithium niobate in compression to the unstrained structures. The decrease in the bandgap is largest for the tensile strain of 20% among all the applied strains. Further, visible light absorption is also improved due to the application of strain. The improvement in visible light absorption is highest for the tensile strain of 20% with absorption completely shifted in the desired visible region. The improved visible absorption due to the applied strain makes Fe-doped lithium niobate a potential candidate for optoelectronics and solar applications. [ABSTRACT FROM AUTHOR]