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The features of photoluminescence (PL) of hybrid nanostructures based on InP/InAsP/InP nanowires array with deposited colloidal CdSe/ZnS-trioctylphosphine oxide quantum dots at increasing pump power have been studied. Pumping was carried out by 10 ps laser pulses duration with 1 MHz repetition rate at 532 nm wavelength in the quasi-resonant region of QDs absorption. It has been established, that PL maximum of the nanostructure shifts hypsochromically with increasing of laser power, revealing a gradual dominance of the bands of its components. This PL manifestation is explained by the cascade filling of excited excitonic states, accompanied by the Auger recombination processes and light quenching. The role of free carriers absorption and energy exchange between excitonic states at high pump intensities is noted, as well as a sharp PL duration reduction associated with an increase of stimulated processes in absorption. [ABSTRACT FROM AUTHOR]

An innovative strategy to reduce water pollution is adsorption-assisted photocatalysis. A novel mesoporous heterogeneous adsorbent MOF-5-based photocatalysts were successfully synthesized by a green method from plastic waste through a one-step solvothermal process. Additionally, ZnFe2O4 nanocrystals were physically ground with commercial Degussa P25 at room temperature to prepare ZF/P nanocomposite catalysts. These catalysts demonstrated significant photocatalytic activity for the removal of BTX from wastewater. BTX was successfully degraded in an aqueous solution utilizing integrated adsorption and photocatalytic degradation using the newly developed ZF/P@MOF-5 samples with 0.01% of ZF/P. The in-depth characterization of the ZF/P@MOF-5 confirmed its positive physicochemical properties, such as porous nature, stability, high surface area, beneficial functional groups on its surface, and photocatalytic activity. PL spectroscopy also shows that the ZF/P-incorporated MOF-5 nanocomposite has a lower electron-hole recombination rate. The as-prepared ZF/P@MOF-5 mesoporous heterogeneous adsorbent-photocatalyst presented high adsorption and maximum degradation of BTX under visible radiations after 180 min. The reusability results demonstrated that 20 P/ZF @MOF-5 composite can be used effectively for up to four cycles, which makes the process more economical. This experimental study demonstrates that the novel ZF/P-incorporated MOF-5 is a potential route to producing photocatalysts for dissociating BTX wastewater that is highly effective, stable, economical, and sustainable. [ABSTRACT FROM AUTHOR]

Multi-exciton generation by multi-photon absorption under low-energy photons can be thought a reasonable method to reduce the risk of optical damage, especially in photoelectric quantum dot (QD) devices. The lifetime of the multi-exciton state plays a key role in the utilization of photon-induced carriers, which depends on the dynamics of the exciton generation process in materials. In this paper, the exciton generation dynamics of the photon absorption under low-frequency light in CdSe QDs are successfully detected and studied by the temporal resolution transient absorption (TA) spectroscopy method. Since the cooling time of hot excitons extends while the rate of auger recombination is accelerated when incident energy is increased, the filling time of defect states is irregular, and exciton generation experiences a transition from single-photon absorption to multi-photon absorption. This result shows how to change the excitation. Optical parameters can prolong the lifetime of excitons, thus fully extracting excitons and improving the photoelectric conversion efficiency of QD optoelectronic devices, which provides theoretical and experimental support for the development of QD optoelectronic devices. [ABSTRACT FROM AUTHOR]

Wide bandgap semiconductor-based photocatalysts are usually limited by their low solar energy conversion efficiency due to their limited absorption solar wavelength, their rapid surface recombination of the photogenerated electron–hole pairs, and their low charge-carrier mobility. Here, we report a novel stepwise solution synthesis for achieving a new photocatalytic core–shell consisting of a titanate nanowire/reduced graphene oxide shell (or titanate/rGO) 1D-nanocomposite. The new core–shell nanocomposite maximized the specific surface area, largely reduced the charge transfer resistance and reaction energy barrier, and significantly improved the absorption of visible light. The core–shell nanocomposites' large on/off current ratio and rapid photo-responses boosted the photocurrent by 30.0%, the photocatalysis rate by 50.0%, and the specific surface area by 16.4% when compared with the results for the pure titanate nanowire core. Our numerical simulations support the effective charge separation on the new core–shell nanostructure, which can help further advance the novel photocatalysis. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysts are being recognized as innovative materials for enhancing water quality and environmental optimization. Nevertheless, the limited activity and quick electron–hole pair recombination under visible light have hindered their widespread use in photocatalysis. Nanomaterials based on carbon dots (CDs) show promising applications due to their excellent light absorption ability. Notably, CDs/semiconductor photocatalysts have emerged as advanced photocatalytic materials. This review summarizes strategies to improve the performance of conventional semiconductor photocatalysts by incorporating CDs. These include TiO2, g‐C3N4, Bi‐based, Cu2O, and ZnO photocatalysts. Various effective synthesis routes for composites are discussed, including morphology optimization, heteroatom doping, heterojunction building, and creation of polymeric hybrids. Ultimately, the challenges and future prospects of CDs/semiconductor photocatalysts are discussed. [ABSTRACT FROM AUTHOR]

Nowadays, environmental problems are increasingly varied and the development of various diseases. Due to its ability to create defect in band gap energy and strong antibacterial activity against a variety of microorganisms, ZnO is used to solve both issues. However, ZnO has a large band gap energy, so it is necessary to decrease band gap by doping. In this study, the synthesis of ZnO and ZnO doped materials (N- and (Mg,B,N)-doped ZnO) through the solid-state was carried out. The phases of doped ZnOs are hexagonal wurtzite, according to the results of the characterization using XRD, Raman spectroscopy, and HR-TEM. Surface morphology for N-doped ZnO does not form agglomeration, while in (Mg,B,N)-doped ZnO, agglomeration occurs due to the difference in charge of B with Zn. The existence of dopant in ZnO lattice was confirmed by EDS and XPS. (Mg,B,N)-doped ZnO has the highest specific surface area (14.388 m2/g) according to the BET analysis. The formation of peaks in 358 nm, 520 nm, and 650 nm during PL examination indicates a reduction in the rate of electron-hole recombination and defects. The recombination rate was confirmed by EIS Nyquist spectra result. The band gap energy owing to doping decreased from 3.13 eV to 3.10 eV and 3.12 eV for N- and (Mg,B,N)-doped ZnO, respectively. The lifetime of undoped ZnO, N-doped ZnO, and (Mg,B,N)-doped ZnO is 0.526, 0.610, and 0.695 ns, respectively. Photocatalyst test results showed that N-doped ZnO and (Mg,B,N)-doped ZnO materials were optimum for degradation of methyl violet for under visible light with degradation efficiency of 89.28 % and 93.24 %, respectively. N-doped ZnO and (Mg,B,N)-doped ZnO produce inhibition zone of 7.18 mm and 14.15 mm for Escherichia coli bacteria and 7.50 mm and 11.80 mm for Staphylococcus aureus bacteria. Additionally, molecular docking studies were used to explain a potential mechanism for in vitro bacterial activity. [ABSTRACT FROM AUTHOR]

The rational design of Z‐scheme heterojunction photosystems based on covalent organic frameworks (COFs) is a promising strategy for harnessing solar energy for hydrogen conversion. Herein, a direct Z‐scheme single‐atom photocatalyst based on COF and metal‐organic ring has been constructed through the supramolecular interactions of coral‐like COF (S‐COF) and photosensitized Pd2L2 type metal‐organic ring (MAC‐FA1). The MAC‐FA1/S‐COF heterojunction exhibits good light absorption, efficient charge separation and transfer, slow electron‐hole recombination, and highly dispersed Pd active sites, enabling an efficient and stable H2 evolution reaction. The optimized 4% MAC‐FA1/S‐COF achieves an H2 evolution rate of 100 mmol g−1 h−1 within 5 h and obtains a total accumulated turn‐over number relative to Pd (TONPd) of 437,685 within 20 h, far superior to S‐COF, MAC‐FA1, M‐5/S‐COF, Pd/S‐COF, and M‐5/Pd/S‐COF, which is one of the highest records among COF‐based photocatalysts for solar‐driven H2 evolution. This is the first work to incorporate photosensitized metal‐organic rings/cages into porous crystalline COFs to form a supramolecular Z‐scheme heterojunction, which has significant potential as a high‐performance photocatalyst for solar‐driven H2 production. [ABSTRACT FROM AUTHOR]

The effect of the simultaneous presence of fluoride (0.15–1.2 mg L−1), bicarbonates (83.6–596 mg L−1), and synthesized goethite (0.3 mg L−1) at typical concentrations often found in groundwater samples was evaluated on the degradation of 2,4‐dichlorophenoxyacetic acid (2,4‐D) at pH 6.9 under simulated sunlight irradiation (300 W m−2) and H2O2 concentrations of 10 mg L−1. The 2,4‐D removal was strongly enhanced by the presence of fluoride. F− could modify the surface of iron (hydr)oxide, leading to the formation of surface Fe–F bonds benefiting the formation of free •OH, producing upward band bending, reducing the electron‐hole recombination, and enhancing the electron transfer to H2O2. On the other hand, bicarbonate may react with •OH generating CO3−• species that could participate in pollutant oxidation, while solar light‐induced H2O2 photolysis also played an important role in removing 2,4‐D. These findings suggest that tuning of iron (hydr)oxides by fluoride could take place in real groundwater, generating photocatalysts with a high activity that could participate, by adding H2O2, in the enhancement of sunlight photoinduced natural abiotic processes for pollutant abatement. [ABSTRACT FROM AUTHOR]

The current study reports on the facile two-step hydrothermal synthesis of heterojunction m-ZnWO4/m-WO3 composite powders for visible light sensitive photocatalytic applications. The ZnWO4 particles start crystallizing on the surface of the WO3 powder in the second stage of the reaction in a basic medium. The phases of the composite powders were confirmed using x-ray diffraction analysis. The monoclinic cubic shaped WO3 and rod shaped ZnWO4 morphologies were disclosed from the field emission scanning electron microscope images. Strong interfacial adhesion between ZnWO4 and WO3 was unveiled from the high-resolution transmission electron microscopy study. The optimized composite 5ZW exhibits a calculated bandgap of 2.58 eV, positioning it within the visible light wavelength range (λ = 400–700 nm). Furthermore, there is a notable enhancement in the average lifetime of the electron–hole pair recombination rate, which is extended to 30.3 ns. The composite 5ZW demonstrated 96% methylene blue dye degradation efficiency within 420 min under visible light irradiation at pH 12. Due to the optimal phase fraction and strong interfacial adhesion between ZnWO4 and WO3, the heterojunction scheme seemed to be highly efficient in the 5ZW composite. Hence, it is believed that a two-step hydrothermal method can be a proficient route to prepare heterojunction composites m-ZnWO4/m-WO3 in alkali conditions with visible light active photodegradation efficiency. [ABSTRACT FROM AUTHOR]

The present work focuses on the synthesis of Prosopis juliflora bark activated carbon supported on TiO2 (PJBAC/TiO2) composite through the sol-gel method for the decolourization of Direct Brown 2 (DB2). The prepared composite was characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. The surface area and pore diameter were explored by the Brunauer−Emmett−Teller method (N2 adsorption/desorption). Furthermore, high-performance liquid chromatography (HPLC) and total organic carbon (TOC) analysis of the treated solution revealed a complete degradation of the dye molecule. The degradation efficiency of the prepared composite was analysed via batch equilibration studies. Maximum removal of DB2 (98%) was achieved at an initial concentration of 100 mg/L, contact time of 210 min, composite dose of 100 mg, and at pH 3. The well-known Freundlich and Langmuir isotherm equations were applied for the evaluation of equilibrium adsorption data. Lagergren and Ho−McKay kinetic models were employed to determine the adsorption rate constant. Additionally, the antimicrobial activity of PJBAC/TiO2 was tested against Staphylococcus aureus, Escherichia coli, and Candida species. These results indicate that doping of TiO2 on PJBAC inhibits the recombination of electron−hole pairs to improve photocatalytic performance in the visible region. [ABSTRACT FROM AUTHOR]

We propose an electrically pumped laser diode based on multiple HgTe quantum wells with band structure engineered for Auger recombination suppression. A model for accounting for hot phonons is developed for calculating the nonequilibrium temperature of electrons and holes. Using a comprehensive model accounting for carrier drift and diffusion, Auger recombination, and hot-phonon effects, we predict of lasing at λ ∼ 3 μ m at room temperature in the 2.1 nm HgTe/Cd 0.85 Hg 0.15 Te quantum well heterostructure. The output power in the pulse can reach up to 600 mW for 100 nanosecond-duration pulses. [ABSTRACT FROM AUTHOR]

The description of carrier dynamics in spatially confined semiconductor nanocrystals (NCs), which have enhanced electron–hole and exciton–phonon interactions, is a great challenge for modern computational science. These NCs typically contain thousands of atoms and tens of thousands of valence electrons with discrete spectra at low excitation energies, similar to atoms and molecules, that converge to the continuum bulk limit at higher energies. Computational methods developed for molecules are limited to very small nanoclusters, and methods for bulk systems with periodic boundary conditions are not suitable due to the lack of translational symmetry in NCs. This perspective focuses on our recent efforts in developing a unified atomistic model based on the semiempirical pseudopotential approach, which is parameterized by first-principle calculations and validated against experimental measurements, to describe two of the main nonradiative relaxation processes of quantum confined excitons: exciton cooling and Auger recombination. We focus on the description of both electron–hole and exciton–phonon interactions in our approach and discuss the role of size, shape, and interfacing on the electronic properties and dynamics for II–VI and III–V semiconductor NCs. [ABSTRACT FROM AUTHOR]

In conventional hexagonal InGaAlN multiple-quantum-well (MQW) (h-) light-emitting diodes (LEDs), carrier leakage from QWs is the main source of internal quantum efficiency (IQE) degradation without contributing to the LED efficiency droop. Our analysis based on the newly developed Open Boundary Quantum LED Simulator indicates that radiative recombination is hampered by the poor electron–hole wavefunction overlap induced by strong internal polarization for which QW carriers mostly recombine via Auger scattering rather than by radiative processes. By contrast, in non-polar h-LEDs, the IQE peak doubles its value compared to conventional h-LEDs while quenching the efficiency droop by 70% at current density of 100 A/cm2. Those effects are further enhanced in cubic InGaAlN MQW (c-) LEDs for which the IQE peak increases by an additional 30%, and the efficiency droop is further reduced by 80% compared to non-polar h-LEDs, thanks to the larger optical transition matrix element and the strong electron–hole wavefunction overlap in c-LEDs. Overall, a c-LED with a low efficiency droop of 3% at 100 A/cm2 is anticipated, paving a clear pathway toward ultimate solid-state lighting. [ABSTRACT FROM AUTHOR]

We applied hot-carrier extraction to particulate photocatalysts for artificial photosynthetic reactions including water splitting for H2 production and CO2 reduction to CO and HCOOH, and elucidated promising features of hot-carrier photocatalysts (HC-PCs). We designed a specific structure of the HC-PC; a semiconductor core in which thermalization of photo-generated carriers is significantly suppressed is surrounded by a shell whose bandgap is wider than that of the core. Among the photo-generated hot carriers in the core, only carriers whose energies are larger than the shell bandgap are extracted passing through the shell to the active sites on the shell surface. Thus, the shell functions as an energy-selective contact. We calculated the upper bounds of the rates of the carrier supply from the core to the active sites using a newly constructed detailed-balance model including partial thermalization and nonradiative recombination of the carriers. It has been revealed that the HC-PCs can yield higher carrier-supply rates and thus potentially higher solar-to-chemical energy conversion efficiencies for H2 and CO production than those of conventional photocatalysts with the assistance of intraband transition and Auger recombination/impact ionization. It should be noted, however, that one of the necessary conditions for efficient hot-carrier extraction is sufficiently large carrier density in the core, which, in turn, requires concentrated solar illumination by several hundreds. This would raise rate-limiting problems of activities of the chemical reactions induced by the photo-generated carriers and material-transfer properties. [ABSTRACT FROM AUTHOR]

Plasmon-induced charge transfer has been studied for the development of plasmonic photodiodes and solar cells. There are two mechanisms by which a plasmonic nanoparticle can transfer charge to an adjacent material: indirect transfer following plasmon decay and direct transfer as a way of plasmon decay. Using single-particle dark-field scattering and photoluminescence imaging and spectroscopy of gold nanorods on various substrates, we identify linewidth broadening and photoluminescence quantum yield quenching as key spectroscopic signatures that are quantitatively related to plasmon-induced interfacial charge transfer. We find that dark-field scattering linewidth broadening is due to chemical interface damping through direct charge injection via plasmon decay. The photoluminescence quantum yield quenching reveals additional mechanistic insight into electron–hole recombination as well as plasmon generation and decay within the gold nanorods. Through these two spectroscopic signatures, we identify charge transfer mechanisms at TiO2 and indium doped tin oxide interfaces and uncover material parameters contributing to plasmon-induced charge transfer efficiency, such as barrier height and resonance energy. [ABSTRACT FROM AUTHOR]

We report on the spin and occupation noise of a single, positively charged (InGa)As quantum dot emitting photons in the telecommunication C-band. The spin noise spectroscopy measurements are carried out at a temperature of 4.2 K in dependence on intensity and detuning in the regime beyond thermal equilibrium. The spin noise spectra yield in combination with an elaborate theoretical model the hole-spin relaxation time of the positively charged quantum dot and the Auger recombination and the electron-spin relaxation time of the trion state. The extracted Auger recombination time of this quantum dot emitting at 1.55 μ m is comparable to the typical Auger recombination times on the order of a few μ s measured in traditionally grown InAs/GaAs quantum dots emitting at around 900 nm. [ABSTRACT FROM AUTHOR]

Experiments reported that alkaline earth metal dopants greatly prolong carrier lifetime and improve the performance of perovskite solar cells. Using state-of-the-art ab initio time-domain nonadiabatic molecular dynamics (NAMD), we demonstrate that incorporation of alkaline earth metals, such as Sr and Ba, into MAPbI3 (MA = CH3NH3+) lattice at the lead site is energetically favorable due to the largely negative formation energies about −7 eV. The replacement widens the bandgap and increases the open-circuit voltage by creating no trap states. More importantly, the substitution reduces the mixing of electron and hole wave functions by pushing the hole charge density away from the dopant together with no contribution of Sr and Ba to the conduction band edge state, thus decreasing the NA coupling. The high frequency phonons generated by enhanced atomic motions and symmetry breaking accelerate phonon-induced loss of coherence. The synergy of the three factors reduces the nonradiative recombination time by a factor of about 2 in the Sr- and Ba-doped systems with respect to pristine MAPbI3, which occurs over 1 ns and agrees well with the experiment. The study highlights the importance of various factors affecting charge carrier lifetime, establishes the mechanism of reduction of nonradiative electron–hole recombination in perovskites upon alkaline earth metal doping, and provides meaningful insights into the design of high performance of perovskite solar cells and optoelectronics. [ABSTRACT FROM AUTHOR]

Transition metal-based perovskites have emerged as highly promising and economically advantageous semiconductor materials due to their exceptional performance in optoelectronics, photovoltaic, photocatalysis, and photoluminescence. In this study, we employed a microwave-assisted hydrothermal process to produce a Cu-doped NiMnO3 nanocomposite electrode material. The appearance of a peak corresponding to the (110) plane with a 2θ value of 36.6° confirmed the growth of the rhombohedral NiMnO3 crystal structure. The presence of metal–oxygen bonds in NiMnO3 was confirmed through FTIR spectra. XPS validates the chemical composition, providing additional support for the results obtained from XRD and FT-IR analyses. FE-SEM affirmed the anisotropic growth of small sphere-like structures that agglomerated to form broccoli-like shapes. Cu doping modified the band gap, reducing it from 2.2 to 1.7 eV and enhancing its photoluminescent (PL) activity by introducing defects. The increase in PL intensity (visible light luminescent intensity) can be attributed to a concurrent rise in complex defects and the rate of recombination of electron–hole pairs. Finally, the electrochemical activity demonstrated the pseudo-capacitor behavior of the synthesized material, with capacitance values increasing as the copper (Cu) content in the parent lattice increased. [ABSTRACT FROM AUTHOR]

In the photocatalytic processes of ferroelectric semiconductor materials, how to induce a depolarized electric field (Edp) by polarization to reduce the electron–hole recombination rate is still a big problem. Here, the ABO3-type K0.5Na0.5NbO3 (KNN) material is modified by Nd and Ni elements at A/B sites to narrow the band gap and maintain the room-temperature ferroelectric behavior. The 0.96KNN–0.04NdNiO3 sample shows the narrowed band gap (∼2.75 eV) and high residual polarization value (∼11.56 μC cm−2). After high-field poling, the hydrogen production rate of the sample in the full spectrum reaches 926.28 μmol g−1 h−1, indicating an increase of approximately 5 times compared to the 170.45 μmol g−1 h−1 of the unpoled sample. The improved performance of photocatalytic hydrogen production mainly results from the reduction of band gap and the formation of Edp after polarization. The change in the position of the top of the valence band after sample polarization reveals that high-field poling can improve charge transport efficiency by energy band bending. [ABSTRACT FROM AUTHOR]

Designing efficient catalysts with strong redox characteristics and high visible light absorption is of particular interest in the field of photocatalysis. In this study, we synthesized an active and cost-effective photocatalyst by combining MOF-derived La/Fe bimetallic LaFeO3 porous nanosheets with hydrothermally synthesized CdS nanorods. Several p-LaFeO3/n-CdS photocatalysts with different concentrations (wt%) of LaFeO3 were synthesized, and their physicochemical properties were characterized by standard analytical techniques such as UV-vis DRS, FTIR, XRD, BET, SEM, TEM, EDX and XPS. The photocatalytic degradation performance of the synthesized materials was evaluated using chromophoric dyes such as rhodamine B (RhB) and congo red (CR) and antibiotics such as tetracycline (TC) and oxytetracycline (OTC) under visible light irradiation in aqueous suspension. The as-synthesized 15 wt% p-LaFeO3/n-CdS (15 LC) heterojunction photocatalyst exhibited remarkable photocatalytic degradation performance against RhB (96%, 30 min), CR (98%, 25 min), TC (80%, 100 min), and OTC (78.6%, 75 min). The reactive oxygen species such as O2˙−, h+, and ˙OH were involved in the degradation process, which was monitored through scavenger tests. The heterojunction photocatalyst effectively suppressed photoinduced electron–hole pair recombination and facilitated interfacial charge transfer. Based on experimental data and projected energy band positions, a type II mechanism is proposed to elucidate the photocatalytic degradation of organic contaminants, emphasizing the redox capabilities and broad visible light absorption of the synthesized photocatalyst. The phototransformation of 4-nitrophenol to 4-aminophenol and adsorption isotherms were also done using the 15 LC heterojunction photocatalyst, whereas in the case of the adsorption isotherms the curve fitted the Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

Understanding Auger recombination in (In,Ga)N-based quantum wells is of central importance to unravelling the experimentally observed efficiency 'droop' in modern (In,Ga)N light emitting diodes (LEDs). While there have been conflicting results in the literature about the importance of non-radiative Auger recombination processes for the droop phenomenon, it has been discussed that alloy fluctuations strongly enhance the Auger rate. However, these studies were often focused on bulk systems, not quantum wells, which lie at the heart of (In,Ga)N-based LEDs. In this study, we present an atomistic analysis of the carrier density dependence of the Auger recombination coefficients in (In,Ga)N/GaN quantum wells. The model accounts for random alloy fluctuations, the connected carrier localisation effects, and carrier density dependent screening of the built-in polarisation fields. Our studies reveal that at low temperatures and low carrier densities the calculated Auger coefficients are strongly dependent on the alloy microstructure. However, at elevated temperatures and carrier densities, where the localised states are starting to be saturated, the different alloy configurations studied give (very) similar Auger coefficients. We find that over the range of carrier densities investigated, the contribution of the electron-electron–hole related Auger process is of secondary importance compared to the hole-hole-electron process. Overall, for higher temperatures and carrier densities, our calculated total Auger coefficients are in excess of 10−31 cm6 s−1 and may reach 10−30 cm6 s−1, which, based on current understanding in the literature, is sufficient to result in a significant efficiency droop. Thus, our results are indicative of Auger recombination being an important contributor to the efficiency droop in (In,Ga)N-based light emitters even without defect-assisted processes. [ABSTRACT FROM AUTHOR]

A library of large organic cation spacers is available for engineering the performance of layered two‐dimensional (2D) halide perovskite devices. Despite extensive photophysics studies, there remains a research gap over the structure‐function relations in 2D perovskites, especially the underlying factors influencing the Auger recombination (AR) process. Herein, the contributions of exciton binding energy, exciton‐phonon coupling, and defects/film morphology to the AR process in 2D perovskites are examined. Phenyl‐alkyl‐ammonium cations with different lengths of attached alkyl groups, commonly used in blue light‐emitting diodes, are investigated. The findings reveal an order of magnitude higher threshold carrier density for the AR onset as well as a reduced AR in cations with longer alkyl chain length. Although possessing similar exciton binding energies, the exciton‐phonon coupling strength is found to play a major role in reducing the AR rate, with a smaller contribution from the defect states/film morphology. The findings can help provide further guidance on organic spacer cation engineering for highly efficient 2D perovskite light emitters. [ABSTRACT FROM AUTHOR]

Our successfully prepared an efficient photo-Fenton composite catalyst, denoted as 1T-2H MoS 2 @TP/PPy (MTP), by copolymerizing tea polyphenol (TP) and polypyrrole (PPy) onto the surface of 1T-2H MoS 2. The inclusion of tea polyphenol and the iron coupling structure (TP-Fe2+/Fe3+) not only resolved the iron source issue but also significantly broadened the pH range within which MTP operates effectively. The introduction of PPy brought about remarkable improvements in the catalyst's stability, and it played a pivotal role in modifying the energy band structure of 1T-2H MoS 2 , thus facilitating the separation of photogenerated electron-hole pairs. Additionally, elevating the solution temperature promotes the photo-Fenton process. [Display omitted] In this study, we present the successful development of a unique photo-Fenton catalyst, 1T-2H MoS 2 @TP/PPy (MTP), achieved through the coating of a copolymer of tea polyphenol (TP) and polypyrrole (PPy) onto the surface of heterophase molybdenum disulfide (1T-2H MoS 2). This innovative approach involves the integration of hydrothermal synthesis with copolymerization techniques. Our strategy utilizes nanoflower-like 1T-2H MoS 2 as the foundational framework, which is then enveloped in TP and PPy copolymer. This innovative approach involves the integration of hydrothermal synthesis with copolymerization techniques. Our strategy utilizes nanoflower-like 1T-2H MoS 2 as the foundational framework, which is then enveloped in TP and PPy copolymer. This distinctive architecture demonstrates exceptional catalytic performance owing to the hetero-phase entanglement of 1T-2H MoS 2 , which provides a diverse array of active sites. The coupled structure of TP and iron (TP-Fe2+/Fe3+) effectively overcome the limitation associated with the iron source. The incorporation of PPy not only reduces the recombination of photogenerated electron-hole pairs but also enhances the stability of 1T-2H MoS 2. Remarkably, our experiments on the degradation of methylene blue (MB) and tetracycline (TC) degradation demonstrate that TP-Fe2+/Fe3+ significantly expands the pH applicability range of the MTP composite catalyst. Additionally, we examine several factors, including different catalysts, H 2 O 2 addition, variations in light intensity, solution pH, temperature fluctuations, and the role of active species, to comprehensively understand their impact on the photo-Fenton degradation process. In conclusion, MTP composite exhibits robust catalytic stability and demonstrates a broad pH utilization range in the photo-Fenton oxidation process, highlighting its promising potential for a wide range of applications. [ABSTRACT FROM AUTHOR]

Hydrogen is becoming more widely accepted as a potential energy carrier due to zero emissions, superior energy capacity, and ecological sustainability. It can be produced in a number of ways, but photocatalytic water splitting using sunlight has recently attracted attention as a sustainable option. Photocatalysts based on semiconductors, especially TiO 2 photocatalysts, have been the subject of extensive study because of their desirable physicochemical properties. There are still obstacles to overcome, however, including a wide bandgap, sluggish electron-hole recombination, and the potential for excessive H 2 generation. Numerous strategies such as doping, defect engineering, dye sensitization, and semiconductor coupling have been investigated with the goal of improving the performance of TiO 2 by discovering solutions to these limitations. This article summarizes current research on the multiple parameters affecting the photocatalytic process in dynamic H 2 generation. Surface area, particle size, TiO 2 loading, pH, temperature, light source, light intensity, sacrificial reagents, and band gap energy are all important characteristics of photocatalysts. The techno-feasible analysis, current challenges, possibility for subsequent research, and the potential for H 2 production by the photocatalytic water-splitting process are further addressed in this article. [Display omitted] • Recent attempts involving TiO 2 -based photocatalysts to produce H 2 via photocatalytic water-splitting have been addressed. • Various strategies to improve TiO 2 photocatalytic efficiency have been proposed for practical applications. • Factors affecting the TiO 2 -based photocatalytic efficiency were reviewed. • Techno feasibility analysis water-splitting have been addressed for commercialization. • Several challenges, future perspectives and strategies for development have been proposed. [ABSTRACT FROM AUTHOR]

Direct Z-schemes for photocatalytic overall water splitting for hydrogen generation are constructed for Sc 2 CCl 2 /MoTe 2 and Sc 2 CCl 2 /Hf 2 CO 2 heterostructures on the basis of the calculated band alignment and built-in electric field. Solar-to-hydrogen efficiency (η STH ′), which is evaluated using the overpotentials of the band edges and band gaps, can reach 22.09 % for Sc 2 CCl 2 /MoTe 2 and 19.07 % for Sc 2 CCl 2 /Hf 2 CO 2. Tensile strains have little effect on η STH ′. Compressive strains substantially increase the η STH ′ of Sc 2 CCl 2 /MoTe 2 and boost that of the Sc 2 CCl 2 /Hf 2 CO 2 heterostructure only slightly. Nonadiabatic dynamics simulations reveal that the lifetime of the photogenerated electron in one of the stacking patterns of Sc 2 CCl 2 /MoTe 2 is much larger than that of the other configurations, indicating that the reduction ability of the electron is well protected. However, the interlayer electron–hole recombination in Sc 2 CCl 2 /MoTe 2 is faster than that in Sc 2 CCl 2 /Hf 2 CO 2 , implying that the Z-schemes with the former are more efficient than the Z-schemes with the latter. The hydrogen and oxidation evolution reactions with the two heterostructures are thermodynamically feasible but the reactions cannot proceed spontaneously. These findings provide a helpful guide for the development of photocatalytic materials for photocatalytic hydrogen generation from overall water splitting based on the title heterostructures. [Display omitted] • Maximum solar-to-hydrogen efficiency of the constructed schemes can reach 22.09 %. • 4 % compressive biaxial strain can boost the efficiency of Sc 2 CCl 2 /MoTe 2 to 33.77 %. • Reduction ability of SM-AA is well protected by its long electron transfer time. • Minimum Gibbs free energy of HER/OER on the heterostructures reaches 0.89/1.99 eV. [ABSTRACT FROM AUTHOR]

Heterostructure engineering stands out as a potent strategy for advancing photocatalytic H2 production. In the present study, various ratios of 1T/2H‐MoSe2 are synthesized by modulating the quantity of the reducing agent. Notably, the sample characterized by the highest 1T phase content exhibits the lowest charge transfer resistance and superior absorption of visible light. Subsequently, MoSe2 is incorporated with CdZnS to form the heterostructures. Remarkably, the highest H2 production rate at 6.4 mmol g−1 h−1 of the sample, surpassing that of CdZnS by a factor of six, is demonstrated. The improved H2 production performance is attributed to the increased absorption of visible light and the suppression of electron–hole recombination, thereby enhancing overall H2 production. The heterostructures exhibit unparalleled photocatalytic efficiency, owing to the fast electron mobility inherent in the 1T‐MoSe2, resulting in a substantial improvement in carrier separation. These findings highlight the significance of tuning the 1T/2H ratio of MoSe2 for augmenting photocatalytic H2 production, showing the potential of heterostructure engineering for catalytic applications. [ABSTRACT FROM AUTHOR]

Synthesis of ammonia from photocatalytic N2 reduction is challenging due to the fast recombination of electron–hole pairs and the low selectivity of N2 on catalysts. This can be addressed by creating heterojunctions to separate the photogenerated carriers adequately. In this regard, BW/g‐C3N4 is synthesized and the weight percentage of g‐C3N4 is varied. The best photocatalytic activity for N2 reduction reaction (N2RR) is achieved with a ratio of BW/gC3N4 in 3.5:2 ratio, deemed to be the optimized heterojunction. N2‐temperature programmed desorption analysis shows outstanding chemisorption of N2 adsorbed on the BW/g‐C3N4 surface compared to pristine g‐C3N4 and BW. Additionally, forming a heterojunction enhances the charge transfer process and well‐separated electron–hole pairs, significantly boosting the water oxidation process on the catalytic surface. Photoelectrochemical analysis reveals that BW/g‐C3N4 exhibits the shortest hole relaxation lifetime and higher current density than its pristine counterparts. The robust contact between g‐C3N4 and BW reduces the work function of BW/g‐C3N4 based on ultraviolet photoelectron spectroscopy data. Ammonia production with the optimized BW/gC3N4‐3.5:2 is 5.3 and 2.1 times higher than pure g‐C3N4 and Bi2WO6, respectively. Meanwhile, BW/g‐C3N4 demonstrates excellent photocatalytic activity toward antibiotic pollutant degradation as well. After 150 min of visible light irradiation, the removal of 94% ciprofloxacin (CIP) is observed. Finally, a possible mechanism is proposed for photocatalytic N2RR and CIP degradation. [ABSTRACT FROM AUTHOR]

The demand for effective sterilization methods, particularly in the wake of the Covid-19 pandemic, has sparked interest in the use of deep ultraviolet (DUV) radiation for disinfection. The high risk of skin/eye exposure to the high-energy DUV radiation requires the integration of DUV and visible (VIS) LED chips to sterilize and indicate its operation simultaneously in the portable sterilization devices. However, conventional double-chip integration suffers from high power consumption and fabrication complexity. This study sets out to explore the monolithic integration of DUV and VIS LEDs for the radiative sterilization application. This is accomplished by cascading AlGaN/AlGaN/AlGaN multiple quantum wells (QWs) and GaN/InGaN/GaN QWs through the compositional grading AlGaN cascade region. The inevitable overflown electrons from DUV QWs are deliberately introduced into the VIS QWs, allowing for the electron–hole recombination and the simultaneous emission of VIS light. Both experiment and simulation results confirm the feasibility of the proposed dual-wavelength LED integration. The proposed DUV&VIS LED shows an external quantum efficiency and wall-plug efficiency of 2.03% and 1.54% at 40 mA, respectively. This study establishes a quantitative framework for the monolithic integration of DUV and VIS LEDs for radiative sterilization, which has the potential to replace the current technique of using discrete DUV and VIS double-chip configurations. [ABSTRACT FROM AUTHOR]

Herein, magnetic (Co3+/Co2+)-integrated SnO2, SnO2/ZnFe2O4, and ZnFe2O4 composites have been prepared from triply distilled water and 30% of isopropanol in the water medium. The phase evolution, microstructure, and magnetism were investigated successfully and tested for cationic dye wastewater degradation containing Rhodamine 6G and Methylene Blue under ultra-violet irradiation. Composite spheres are attributed to efficient heterojunction interfaces between ZnFe2O4 and SnO2 semiconductors with the support of (Co3+/Co2+) nanoparticles. The results provide a simple, low-cost, environmentally friendly, and scalable method of ternary composites to degrade mixed dyes. Co3+/Co2+-implanted SnO2/ZnFe2O4 offered narrowed bandgap energy, more light absorption, diminishing electron–hole recombination, and more charge carriers toward cationic dye wastewater than the binary components. The rate constant of Rhodamine 6G degradation was observed at 0.0237 min−1, and Methylene Blue degradation was observed at 0.0187 min−1 at 90 min under UV (λ = 365 nm) irradiation. Capturing studies of various organic reactive species and mechanisms of composites was also proposed in detail. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials have emerged as highly promising photocatalysts for solar-driven water splitting. They have garnered significant interest owing to their large specific surface areas and short carrier migration distances. Our study focused on the theoretical prediction of promising photocatalysts for solar-driven water splitting in XAu 4 Y (X, Y= Se, Te) monolayers and their corresponding heterostructures using first-principles calculations. XAu 4 Y are semiconductors with indirect bandgaps of 1.27–1.54 eV. Owing to their appropriate band edges, SeAu 4 Se and SeAu 4 Te were found to be suitable for solar-driven water splitting. Importantly, SeAu 4 Te achieved a Janus-induced internal electric field of 0.80 V/Å, which favored the separation of photogenerated carriers, thus improving the photocatalytic efficiency. Further, SeAu 4 Se/TeAu 4 Te and SeAu 4 Se/TeAu 4 Se heterostructures were predicted to be high-performance Z(S)-scheme photocatalysts for hydrogen evolution with strong redox abilities, efficient separation of photogenerated carriers, and enhanced light absorptions. Our findings may provide valuable insights for realizing high-performance photocatalysts for water splitting. [Display omitted] • SeAu 4 Se and SeAu 4 Te are promising solar-driven photocatalysts for water splitting. • Janus SeAu 4 Te achieve a built-in electric field to restrain electron-hole recombination. • SeAu 4 Se/TeAu 4 Te, SeAu 4 Se/TeAu 4 Se, and TeAu 4 Te/SeAu 4 Te are staggered band alignments. • SeAu 4 Se/TeAu 4 Te and SeAu 4 Se/TeAu 4 Se are efficient Z(S)-scheme charge transport mechanisms. [ABSTRACT FROM AUTHOR]

A supramolecular photovoltaic strategy is applied to enhance power conversion efficiencies (PCE) of photoelectrochemical devices by suppressing electron–hole recombination after photoinduced electron transfer (PET). Here, the author exploit supramolecular localization of the redox mediator—in close proximity to the dye—through a rotaxane topology, reducing electron–hole recombination in p‐type dye‐sensitized solar cells (p‐DSSCs). Dye PRotaxane features 1,5‐dioxynaphthalene recognition sites (DNP‐arms) with a mechanically‐interlocked macrocyclic redox mediator naphthalene diimide macrocycle (3‐NDI‐ring), stoppering synthetically via click chemistry. The control molecule PStopper has stoppered DNP‐arms, preventing rotaxane formation with the 3‐NDI‐ring. Transient absorption and time‐resolved fluorescence spectroscopy studies show ultrafast (211 ± 7 fs and 2.92 ± 0.05 ps) PET from the dye‐moiety of PRotaxane to its mechanically interlocked 3‐NDI‐ring‐acceptor, slowing down the electron–hole recombination on NiO surfaces compared to the analogue. p‐DSSCs employing PRotaxane (PCE = 0.07%) demonstrate a 30% PCE increase compared to PStopper (PCE = 0.05%) devices, combining enhancements in both open‐circuit voltages (VOC = 0.43 vs 0.36 V) and short‐circuit photocurrent density (JSC = −0.39 vs −0.34 mA cm−2). Electrochemical impedance spectroscopy shows that PRotaxane devices exhibit hole lifetimes (τh) approaching 1 s, a 16‐fold improvement compared to traditional I−/I3−‐based systems (τh = 50 ms), demonstrating the benefits obtained upon nanoengineering of interfacial dye‐regeneration at the photocathode. [ABSTRACT FROM AUTHOR]

The document titled "Advanced Inorganic Semiconductor Materials" is a summary of a special issue that explores current research and ideas in the field of inorganic semiconductors. The issue includes nine articles and two topical reviews that cover various topics, such as 2D materials, quantum dots, avalanche photodiodes, and perovskites. Each article delves into different aspects of these materials, including their optical, mechanical, and electronic properties, as well as their potential applications in optoelectronic devices. The findings presented in the articles contribute to the understanding and development of advanced inorganic semiconductor materials for various applications. The document expresses gratitude to the contributors and reviewers for their valuable contributions to the special issue. [Extracted from the article]

The rapid growth of industrialization has led to the uncontrolled pollution of the environment, and rapid action is needed. This study synthesized Ag/TiO2/polyvinyl alcohol (PVA) nano photocatalyst for promising light-derived photocatalytic removal of heavy metal ions. The design of experiment (DOE) was used to study the effect of important factors (pH, reaction time, and photocatalyst dosage) to maximize the final performance of the photocatalyst. In the optimized condition, the Ag/TiO2/PVA nano-photocatalyst removed more than 94% of Cr6+ in 180 min, and the efficiency was more than 70% for Cu2+, Zn2+, and Ni2+ metal ions. The adsorption of the heavy metal ions on the photocatalyst was described well with the Langmuir isotherm, while the pseudo-second-order linear kinetic model fitted with the experimental data. The nano-photocatalyst's stability was confirmed after maintaining its performance for five successive runs. The enhanced photocatalytic activity for the heavy metal ions removal can be attributed to the presence of metallic silver nanoparticles (electron transfer and plasmonic fields mechanisms) and PVA, which delayed the recombination of electron–hole. The synthesized ternary Ag/TiO2/PVA nano-photocatalyst showed promising performance for the elimination of heavy metal ions and can be used for environmental remediation purposes. [ABSTRACT FROM AUTHOR]

This paper presents a Computer‐aided design (CAD) model for a‐IGZO thin film transistors (TFTs) by adapting SPICE level‐61 RPI a‐Si: H (Hydrogenated Amorphous Silicon) TFT model and level‐62 RPI Poly‐Si (Poly Silicon) TFT model. This work provides a complete understanding of SPICE level‐61 and 62 model parameters, which must be tuned for a‐IGZO TFT simulation. The adapted SPICE models of level‐61 and level‐62 could model all regions of operation of the TFT, that is, above‐threshold and below‐threshold regions. Adapted RPI poly‐Si model also shows the kink effect in ZnO thin film transistors (TFTs) due to the recombination of electron–hole pairs in the channel via boundary trap states present in the poly‐Si TFTs thereby increasing the drain current in the transistors above pinch‐off region. The extracted performance parameters of the adapted models were found to be contiguous with experimental results. The maximum deviation in the subthreshold slope is approximately 5 mV/decade for level‐61 a‐Si TFT, and for level‐62 poly‐Si TFT, deviation in the subthreshold slope is even less, that is, 0.2 mV/decade. The experimental and simulated characteristics, extracted on‐to‐off ratio, negative bias reverse saturation current, and threshold voltage were almost similar. However, an average deviation of 2.4% and 2.27% was observed in the output characteristics of the adapted level‐61 and level‐62 models, respectively. [ABSTRACT FROM AUTHOR]

Dual‐band optical signals, consisting of visible and infrared wavelengths, hold significant potential in various fields such as night vision, vehicle safety, bioimaging, and optical communications. Consequently, considerable attention has focused on modulation techniques for visible‐infrared dual‐band signals, including various electrochromic devices. However, these devices often suffer from low speeds and complex structures, making them unsuitable for satisfying the current demand for ultrafast on‐chip nanophotonics. Here, an ultrafast, dual‐band selective optical switching is presented in thallium selenide (TlSe), a layered nanomaterial with low‐symmetry. Transient absorption microscopy directly reveals distinct modulation bands in the visible and near‐infrared (NIR) regions. Notably, these bands exhibit orthogonal polarization dependencies, enabling the selective modulation of visible and NIR light via polarization control. Theoretical analysis reveals that the modulation bands in the visible and NIR regions arise from the perpendicularly anisotropic excited‐state absorption of electrons and holes, respectively. This is supported by distinct ultrafast cooling times observed for electrons and holes. The modulations exhibit picosecond‐scale dynamics owing to efficient Auger recombination. These exceptional characteristics highlight the promising nature of low‐symmetry TlSe as a novel material for ultrafast dual‐band nanophotonics. Furthermore, this work provides fundamental insights into anisotropic carrier dynamics, including effective mass‐dependent cooling and many‐body interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] Suppressing the electron-hole recombination rate of catalyst legitimately is one of the effective strategies to improve photocatalytic hydrogen evolution. Herein, carbon-coated metal oxide, ZnFe 2 O 4 @C (ZFO@C), nanoparticles were synthesized and employed to couple with quadrupedal Cd 0.9 Zn 0.1 S (CZS) via an ordinary ultrasonic self-assembly method combined with calcination to form a novel ZFO@C/CZS catalyst with step-scheme (S-scheme) heterojunction. The photocatalytic hydrogen evolution reaction (HER) was conducted to verify the enhanced photoactivity of ZFO@C/CZS. The optimal ZFO@C/CZS exhibits an extraordinary photocatalytic HER rate of 111.3 ± 0.9 mmol g-1 h−1 under visible-light irradiation, corresponding to an apparent quantum efficiency as high as (76.2 ± 0.9)% at 450 nm. Additionally, the as-synthesized ZFO@C/CZS composite exhibits high stability and recyclability. The excellent photocatalytic hydrogen evolution performance should arise from the formed S-scheme heterojunction and the unique ZFO@C core–shell structure, which inhibit electron hole recombination as well as provide more reactive sites. The pathway of S-scheme charge transfer was validated through density functional theory calculations and electrochemical measurements. This work provides a rational strategy for the synthesis of unique magnetic S-scheme heterojunction photocatalysts for water splitting under visible light irradiation. [ABSTRACT FROM AUTHOR]

The sillenite-structured bismuth titanate (Bi12TiO20) is thought to be a viable photocatalyst for environmental remediation. However, the performance of Bi12TiO20 as a photocatalyst is severely constrained by its limited range of light sensitivity and the rapid photoinduced electron-hole pair recombination. A practical and effective way to overcome these limitations is to combine Bi12TiO20 with adequate photocatalysts to create heterojunctions. Here, a one-step solvothermal technique is used to synthesize Bi12TiO20/Bi4Ti3O12 heterojunction (BTO). The electric field that exists between B12TiO20, Bi4Ti3O12 and the closed interfacial contacts had a synergistic effect on the constructed composites, which resulted in high charge transfer abilities. Therefore, the BTO heterojunction demonstrated increased photocatalytic efficacy in the presence of ultraviolet irradiation. The MO removal efficiency of optimal BTO was 97.15%, significantly higher than that of pure Bi2O3 (46.9%). Furthermore, the cycling experiment demonstrated that the BTO heterojunction is stable and reusable. The probable mechanism of photocatalytic MO oxidation over BTO heterojunction was studied by various scavengers. The •OH radicals and holes played essential roles in BTO system of photocatalytic oxidation process. [ABSTRACT FROM AUTHOR]

A novel rGO (Reduced Graphene Oxide)-ZnO/WO3 nanohybrid has tremendous commercialization potential for photocatalytic hydrogen generation because of its cheap production costs, specific optical properties, remarkable stability and conductivity. It decreases charge recombination, improves photoelectronic transit, and broadens visible light absorption with rGO. This study developed a simple nano-casting procedure to include WO3 nanocuboids into rGO-ZnO nanorods formed by hydrothermal treatment with the appropriate amount of ZnO grafted on rGO. Improved photocatalytic activity has been discovered in rGO-ZnO nanocomposite with 1:3 ratios. The optimized powder rGO/ZnO (1:3) nanocomposite paired with WO3 exhibits the maximum photocatalytic hydrogen production activity (13.29 mmoles g−1h−1), which is approximately 1.27 times more active than the powder rGO/ZnO (1:3) nanocomposite (10.46 mmoles g−1 h−1). The contributions of rGO/ZnO (1:3) and integrated WO3 to photocatalytic hydrogen evolution enhancement have been fully investigated through experiment and characterization. The logical design and bottom-up synthesis of eco-friendly energy conversion materials with high performance and low-cost lead to commercialization and become the focal point of this effort. Optimized rGO-ZnO (1:3)/ WO3 heterojunction: a robust photocatalyst with a low band gap exhibits a slow rate of electron-hole recombination and remarkable (13.29 mmole g−1 h−1) solar hydrogen production activity. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) have emerged as prominent contenders in the realm of luminescent nanomaterials over the past decade owing to their tunable optical properties, robust photostability, versatile surface functionalization and doping potential, low toxicity, and straightforward synthesis utilizing environmentally friendly precursors. In this review, we commence with a concise introduction, presenting both top‐down and bottom‐up strategies for the eco‐friendly synthesis of CQDs. Subsequently, we delve into a comprehensive examination of CQDs' structure and optical characteristics, encompassing their ultraviolet–visible absorption properties, surface confinement effects, and surface state emissions contributing to room‐temperature photoluminescence (PL). This review proceeds to elucidate recent advancements in modification strategies for CQDs, specifically focusing on surface oxidation, passivation, and the incorporation of heteroatoms. These strategies serve to afford control over the physicochemical properties, facilitating the enhancement of PL through the decoration of highly visible‐responsive CQDs. This enhancement is achieved by suppressing the nonradiative recombination of electron‐hole pairs, enabling red/blue shifts in CQDs for the generation of a full‐color emission spectrum, and regulating the band‐gap and surface states to broaden the photoabsorption range. Finally, we offer an overview of the most recent developments in the applications of fluorescent CQDs, emphasizing their utility in biomedicine, fluorescent sensors, lighting, and displays, as well as photocatalysis. [ABSTRACT FROM AUTHOR]

Hematite is one of the most promising photoanode materials for the study of photoelectrochemical (PEC) water splitting because of its ideal bandgap with sufficient visible light absorption and stability in alkaline electrolytes. However, owing to the intrinsically high electron-hole recombination, the PEC performance of hematite is still far below that expected. The efficient charge separation can be achieved via growth of FeOOH on hematite photoanode. In this study, hematite nanostructures were successfully grown on the surface of iron foil by the simple immersion deposition method and thermal oxidation treatment. Furthermore, cocatalyst FeOOH was successfully added to the hematite nanostructure surface to improve charge separation and charge transfer, and thus promote the photoelectrochemical water splitting. By utilizing the FeOOH overlayer as a cocatalyst, the photocurrent density of hematite exhibited a substantial 86% increase under 1.5 VRHE, while the onset potential showed an apparent shift towards the cathodic direction. This can be ascribed to the high reaction area for the nanostructured morphology and high electrocatalytic activity of FeOOH that enhanced the amount of photogenerated holes and accelerated the kinetics of water splitting. [ABSTRACT FROM AUTHOR]

Photocatalysts show great potential as compounds for restoring contaminated water and wastewater resources. The study aims to synthesize a composite with high photocatalytic potential under visible light to photodegrade the organic pollutants. Ag/Ag3PO4@ TiO2 were synthesized by doping Ag and Ag3PO4 on TiO2. The composite was characterized using X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy, Field emission scanning electron microscopy, and Energy-dispersive X-ray spectroscopy analyses, and its photodegradation ability was investigated by methylene blue. Utilization of pure TiO2 yielded a removal efficiency that was merely half of the efficiency achieved when using modified particles, owing to the reduction of TiO2 s band gap from 3.2 to 1.94 eV. In addition to its enhanced photocatalytic performance under visible light, the synthesized Ag/Ag3PO4@TiO2 photocatalyst demonstrated remarkable efficiency in removing dyes such as methylene blue from aqueous solutions. The removal efficiency at pH less than 7 in 50 ppm methylene blue solution using 3 g/l photocatalyst over 45 min visible light irradiation was approximately 90 percent. Under sunlight, photocatalytic reactions exhibited an efficiency of over 95 percent within 45 min. It can be concluded that the simultaneous introduction of metallic (Ag) and nonmetallic (PO43−) dopants significantly increases the efficiency of electron–hole recombination suppression in the photocatalyst and also decreases the band gap. [ABSTRACT FROM AUTHOR]

Herein, mesoporous Zn-doped g-C3N4 wrapped CdIn2S4 microsphere nanostructures were fabricated using a simple hydrothermal route. It is found that the CdIn2S4/Zn–g-C3N4 nanocomposite exhibits the most efficient photocatalytic activity for hydrogen evolution. The photocatalytic activity of the CdIn2S4/Zn–g-C3N4 composite presents the optimum performance for hydrogen evolution of 101.74 μmol h−1, which is ∼10.8 and 7.3 times that of pure g-C3N4 and bare CdIn2S4, respectively. The results of varied characterization such as TEM and XPS demonstrate that a tight heterojunction has been successfully built in CdIn2S4/Zn–g-C3N4 nanocomposites, which is highly favorable to limit the recombination of photogenerated electron–hole pairs. Furthermore, Zn could partially replace the C element in the g-C3N4 framework and enhance the separation of photo-induced electrons and holes. Moreover, the incorporation of Zn-doped g-C3N4 nanosheets with mesoporous features considerably improves the photo-stability of CdIn2S4 microspheres. We hope that these CdIn2S4/Zn–g-C3N4 nanocomposites with the tight heterojunction structure may provide new insight into designing novel photocatalysts with high efficiency and excellent stability. [ABSTRACT FROM AUTHOR]

One‐unit‐cell, single‐crystal, hexagonal CuInP2S6 atomically thin sheets of≈0.81 nm in thickness was successfully synthesized for photocatalytic reduction of CO2. Exciting ethene (C2H4) as the main product was dominantly generated with the yield‐based selectivity reaching ≈56.4 %, and the electron‐based selectivity as high as ≈74.6 %. The tandem synergistic effect of charge‐enriched Cu−In dual sites confined on the lateral edge of the CuInP2S6 monolayer (ML) is mainly responsible for efficient conversion and high selectivity of the C2H4 product as the basal surface site of the ML, exposing S atoms, can not derive the CO2 photoreduction due to the high energy barrier for the proton‐coupled electron transfer of CO2 into *COOH. The marginal In site of the ML preeminently targets CO2 conversion to *CO under light illumination, and the *CO then migrates to the neighbor Cu sites for the subsequent C−C coupling reaction into C2H4 with thermodynamic and kinetic feasibility. Moreover, ultrathin structure of the ML also allows to shorten the transfer distance of charge carriers from the interior onto the surface, thus inhibiting electron‐hole recombination and enabling more electrons to survive and accumulate on the exposed active sites for CO2 reduction. [ABSTRACT FROM AUTHOR]

With the rapid development of external minimally invasive or noninvasive therapeutic modalities, ultrasound‐based sonodynamic therapy (SDT) is a new alternative for treating deep tumors. However, inadequate sonosensitizer efficiency and poor biosecurity limit clinical applications. In this study, we prepared an oxygen‐vacancy‐engineered W18O49−x nanobrush with a band gap of 2.79 eV for highly efficient SDT using a simple solvothermal method. The suitable band structures of the W18O49−x nanobrush endows it with the potential to simultaneously produce singlet oxygen (1O2), superoxide anions (⋅O2−), and hydroxyl radicals (⋅OH) under ultrasound irradiation. Additionally, abundant oxygen vacancies that serve as further charge traps that inhibit electron‐hole recombination are incidentally introduced through one‐step thermal reduction. Collectively, the in vitro and in vivo results demonstrate that the oxygen‐vacancy‐engineered W18O49−x nanobrush delivers highly efficient reactive oxygen species (ROS) for SDT in a very biosafe manner. Overall, this study provides a new avenue for discovering and designing inorganic nanosonosensitizers with enhanced therapeutic efficiencies for use in SDT. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO-NPs) are used in various fields such as industrial, environmental remediation, catalytic, and antibacterial applications. However, their ability to absorb visible light is limited due to their high-energy bandgap and fast electron-hole recombination, which restricts their use. To enhance the efficiency of ZnO-NPs in medical and other applications, surface functionality can be modified through doping. Here, we investigated the effects of S and N doping on the energy bandgap of ZnO-NP and their antimicrobial and antioxidant activities. The results showed that the optical bandgap energy of pure ZnO-NPs was 2.98 eV while that of 6% N-ZnO, 4% S-ZnO, and S4-N6-ZnO was 2.78, 2.69, and 2.63 eV, respectively. The energy bandgap reduction is attributed to the changes in the electronic level of zinc oxide as the result of doping. The crystal size of pure ZnO-NPs, 6% N-ZnO, 4% S-ZnO, and S4-N6-ZnO was 29.06, 27.05, 29.02, and 25.06 nm, respectively, as calculated from XRD data using FWHM. Following the bandgap and particle size reduction, the antimicrobial activities of the dual-doped ZnO-NPs surpassed that of the pure ZnO-NPs. Moreover, dual doping improved the antioxidant activity of ZnO-NPs from 52.45% to 88.89% for the optimized concentration. Therefore, incorporating S and N as dual dopants can enhance the functionality and efficiency of ZnO-NPs in various fields. [ABSTRACT FROM AUTHOR]

Diatomic site catalysts (DAC) have better performance with higher metal content and more flexible active sites compared with single atomic site catalysts (SAC). Herein, the authors for the first time achieved Rh2 DAC on loose porous g‐C3N4 hollow nanospheres with N‐vacancies and applied to photocatalytic CO2 reduction reaction, overcoming the current limitations of the low electron–hole recombination rate and prolong the lifetime of the photogenerated carrier. The high specific surface area of hollow nanosphere facilitates the uniform dispersion and anchoring of Rh2 diatomic pairs, while the N‐vacancies induce a stable 3N/Rh‐Rh/1N2C coordination between the carrier and Rh2 diatomic pairs. The local charges on the support framework with N vacancies tend to be transferred to Rh2 diatomic site by 3N/Rh‐Rh/1N2C bridge, which made the charge enriched Rh2 diatomic site become the active center of reaction, enhance charge separation efficiency of Rh2/HCNS‐Nv. Compared with Rh1 SAC, further Density Functional Theory (DFT) calculation confirms that Rh2 DAC can effectively stabilize rate‐limiting intermediates CHO*, and well weaken the C─O bond strength in CH3O* species, promote the generation and separation of CH4, resulting in high CO2 reduction efficiency and CH4 electron selectivity of up to 91.65%. [ABSTRACT FROM AUTHOR]

Diatomic site catalysts (DAC) have better performance with higher metal content and more flexible active sites compared with single atomic site catalysts (SAC). Herein, the authors for the first time achieved Rh2 DAC on loose porous g‐C3N4 hollow nanospheres with N‐vacancies and applied to photocatalytic CO2 reduction reaction, overcoming the current limitations of the low electron–hole recombination rate and prolong the lifetime of the photogenerated carrier. The high specific surface area of hollow nanosphere facilitates the uniform dispersion and anchoring of Rh2 diatomic pairs, while the N‐vacancies induce a stable 3N/Rh‐Rh/1N2C coordination between the carrier and Rh2 diatomic pairs. The local charges on the support framework with N vacancies tend to be transferred to Rh2 diatomic site by 3N/Rh‐Rh/1N2C bridge, which made the charge enriched Rh2 diatomic site become the active center of reaction, enhance charge separation efficiency of Rh2/HCNS‐Nv. Compared with Rh1 SAC, further Density Functional Theory (DFT) calculation confirms that Rh2 DAC can effectively stabilize rate‐limiting intermediates CHO*, and well weaken the C─O bond strength in CH3O* species, promote the generation and separation of CH4, resulting in high CO2 reduction efficiency and CH4 electron selectivity of up to 91.65%. [ABSTRACT FROM AUTHOR]

This study aimed to synthesize a new magnetic photocatalytic nanosystem composed of Ag-CuFe2O4@rGO and to investigate its photodegradation efficiency for two organic pollutants of methylene blue (MB) 4-nitrophenol (4-NP) under visible light irradiation. The synthesized Ag-CuFe2O4@rGO nanocomposites were fully characterized by XRD, TEM, HRTEM, XPS, FTIR, UV and PL analysis which shows well controlled small sized (∼ 10 nm from Scherrer formula) CuFe2O4 NPs with dense and compact loading over rGO sheets. XRD results reveal that cubic spinel structure of CuFe2O4 with nanoparticles (5–10 nm) in shape, which is uniformly, decorated on the surface of the rGO sheets. The band gap energy values of CuFe2O4, Ag-CuFe2O4 and Ag-CuFe2O4@rGO nanoparticles are calculated as 2.76, 2.27 and 2.03 eV, respectively. After incorporation of Ag and rGO into CuFe2O4, the specific surface area was significantly improved to 154 m2/g for Ag-CuFe2O4@rGO nanocomposite. Upon inclusion of the photocatalysts, photodegradation efficiency increased and the Ag-CuFe2O4@rGO composite showed the highest efficiency towards MB (99.5%) and 4-NP (88.7%) followed by the Ag-CuFe2O4. With addition of rGO, the electron-hole recombination declines, thus resulting in a more optimum photocatalytic performance. The rate constant of Ag-CuFe2O4@rGO composite was found to be 0.0985 min−1 for MB and 0.0542 min−1 for 4-NP, respectively. Moreover, the effect of pH, catalyst dosage, and long term stability was thoroughly determined. The improved performance could be attributed to the positive synergistic effect between CuFe2O4 nanoparticles and rGO. The samples were further evaluated by EIS and dynamic photoresponse in order to identify the charge transfer efficiency. The improved photocatalytic mechanism was also explained briefly. [ABSTRACT FROM AUTHOR]