Lifetime Of Photogenerated Carriers Research Articles

Efficient photocatalytic removal of ciprofloxacin through in-situ growth of g-C3N4 on the surface of clinoptilolite

Natural mineral clinoptilolite has many advantages such as porous structure, stability, low price, environmental protection, and simple modification process, making it an ideal choice for wastewater treatment materials. Loading photocatalysts on the surface of zeolite can effectively exert adsorption degradation synergy in wastewater treatment, improve pollutant removal and mineralization capabilities, and further reduce the harm of wastewater to the environment. In this work, g-C3N4 was in-situ grown on the surface of clinoptilolite using a one-step calcination method for efficient photocatalytic removal of the pollutant ciprofloxacin from water. In-situ growth of g-C3N4 on clinoptilolite enables the catalyst to have strong adsorption capacity for pollutants. At the same time, the large specific surface area and extended photo-generated carrier lifetime make the composite photocatalyst exhibit excellent visible light adsorption degradation ability. The CN/CLI-60 with the best photocatalytic performance showed a removal rate of over 90 % of ciprofloxacin within 60 min, much higher than pure g-C3N4 and clinoptilolite. In addition, the pH value, pollutant concentration, catalyst quantity, and cycle stability have all been investigated to evaluate the practical application potential of this catalyst. This work can provide industrial guidance for the rational design of low-cost and high-efficiency photocatalysts using natural clinoptilolite.

Ligand modulation of active center to promote lead-free Cs2AgInCl6 photocatalytic CO2 reduction

Metal halide perovskites (MHP) are potential candidates for the photocatalytic reduction of CO2 due to their long photogenerated carrier lifetime and charge diffusion length. However, the conventional long-chain ligand impedes the adsorption and activation of CO2 molecules in practical applications. Here, a ligand modulation technology is employed to enhance the photocatalytic CO2 reduction activity of lead-free Cs2AgInCl6 microcrystals (MCs). The Cs2AgInCl6 MCs passivated by Oleic acid (OLA) and Octanoic acid (OCA) are used for photocatalytic CO2 reduction. The results show that the surface defects and electronic properties of Cs2AgInCl6 MCs can be adjusted through ligand modulation. Compared with the OLA-Cs2AgInCl6, the OCA-Cs2AgInCl6 catalyst demonstrated a significant improvement in the catalytic yield of CO and CH4. The CO and CH4 catalytic yields of OCA-Cs2AgInCl6 reached 171.88 and 34.15 µmol g−1 h−1 which were 2.03 and 12.98 times higher than those of OLA- Cs2AgInCl6, and the total electron consumption rate of OCA-Cs2AgInCl6 was 615.2 µmol g−1 h−1 which was 3.25 times higher than that of OLA-Cs2AgInCl6. Furthermore, in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs2AgInCl6 MCs induced by ligand modulation. This study illustrates the potential of lead-free Cs2AgInCl6 MCs for efficient photocatalytic CO2 reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts.

Regulating Sulfur Redox Kinetics by Coupling Photocatalysis for High-Performance Photo-Assisted Lithium-Sulfur Batteries.

Challenges such as shuttle effect have hindered the commercialization of lithium-sulfur batteries (LSBs), despite their potential as high-energy-density storage devices. To address these issues, we explore the integration of solar energy into LSBs, creating a photo-assisted lithium-sulfur battery (PA-LSB). The PA-LSB provides a novel and sustainable solution by coupling the photocatalytic effect to accelerate sulfur redox reactions. Herein, a perovskite quantum dot-loaded MOF material serves as a cathode for the PA-LSB, creating built-in electric fields at the micro-interface to extend the lifetime of photo-generated charge carriers. The band structure of the composite material aligns well with the electrochemical reaction potential of lithium-sulfur, enabling precise regulation of polysulfides in the cathode of the PA-LSB system. This is attributed to the selective catalysis of the liquid-solid reaction stage in the lithium-sulfur electrochemical process by photocatalysis. These contribute to the outstanding performance of PA-LSBs, particularly demonstrating a remarkably high reversible capacity of 679 mAh g-1 at 5 C, maintaining stable cycling for 1500 cycles with the capacity decay rate of 0.022% per cycle. Additionally, the photo-charging capability of the PA-LSB holds the potential to compensate for non-electric energy losses during the energy storage process, contributing to the development of lossless energy storage devices.

Vanadium-doped metal-organic framework@Znln2S4 core-shell heterojunction-attenuated photoelectrochemical immunoassay

Considering that cancer has become the second leading cause of death in humans, it is essential to develop an analytical approach that can sensitively detect tumor markers for early detection. We report an attenuated photoelectrochemical (PEC) immunoassay based on the organic-inorganic heterojunction 10MIL-88B(FeV)/ZnIn2S4 (10M88B(FeV)/ZIS) as a photoactive material for monitoring carcinoembryonic antigen (CEA). The 10M88B(FeV)/ZIS heterojunctions have excellent light-harvesting properties and high electrical conductivity, which are attributed to the advantages of both organic and inorganic semiconductors, namely, remarkable photogenerated carrier separation efficiency and long photogenerated carrier lifetime. Horseradish peroxidase (HRP) in the presence of H2O2 can catalyze 3,3′-diaminofenamide (DAB) producing brown precipitates (oxDAB), which is then loaded onto the 10M88B(FeV)/ZIS heterojunction to reduce the photocurrent and enable the quantitative detection of CEA. Under optimal conditions, the photocurrent values of the PEC biosensor are linearly related to the logarithm of the CEA concentrations, ranging from 0.01 ng mL−1 to 100 ng mL−1 with a detection limit (LOD) of 4.0 pg mL−1. Notably, the accuracy of the PEC biosensor is in agreement with that of the human CEA enzyme-linked immunosorbent assay (ELISA) kit.

Rapid and Noise‐Resilient Mapping of Photogenerated Carrier Lifetime in Halide Perovskite Thin Films

AbstractHalide perovskite materials offer significant promise for solar energy and optoelectronics yet understanding and enhancing their efficiency and stability require addressing lateral inhomogeneity challenges. While photoluminescence imaging techniques are employed for the measurement of their opto‐electronic and transport properties, going further in terms of precision requires longer acquisition times. Prolonged exposure of perovskites to light, given their high reactivity, can substantially alter these layers, rendering the acquired data less meaningful for analysis. In this paper, a method to extract high‐quality lifetime images from rapidly acquired, noisy time‐resolved photoluminescence images is proposed. This method leverages concepts of the field of constrained reconstruction and includes the Huber loss function and a specific form of total variation regularization. Through both simulations and experiments, it is demonstrated that the approach outperforms conventional pointwise methods. Optimal acceleration and optimization parameters tailored for decay time imaging of perovskite materials, offering new perspectives for accelerated experiments crucial in degradation process characterization are identified. Importantly, this methodology holds the potential for broader applications: it can be extended to explore additional beam‐sensitive materials, and other imaging characterization techniques and employed with more complex physical models to treat time‐resolved decays.

Photocatalytic Hydrogen Production from Pure Water Using a IEF-11/g-C3N4 S-Scheme Heterojunction.

Construction of S-scheme heterojunction offers a promising way to enhance the photocatalytic performance of photocatalysts for converting solar energy into chemical energy. However, the photocatalytic H2 production in pure water without sacrificial agents is still a challenge. Herein, the IEF-11 with the best photocatalytic H2 production performance in MOFs and suitable band structure was selected and firstly constructed with g-C3N4 to obtain a S-scheme heterojunction for photocatalytic H2 production from pure water. As a result, the novel IEF-11/g-C3N4 heterojunction photocatalysts exhibited significantly improved photocatalytic H2 production performance in pure water without any sacrificial agent, with a rate of 576 μmol/g/h, which is about 8 times than that of g-C3N4 and 23 times of IEF-11. The novel IEF-11/g-C3N4 photocatalysts also had a photocatalytic H2 production rate of up to 92 μmol/g/h under visible light and a good photocatalytic stability. The improved performance can be attributed to the efficient separation of photogenerated charge carriers, faster charge transfer efficiency and longer photogenerated carrier lifetimes, which comes from the forming of S-scheme heterojunction in the IEF-11/g-C3N4 photocatalyst. This work is a promising guideline for obtaining MOF-based or g-C3N4-based photocatalysts with great photocatalytic water splitting performance.

Construction of S-scheme BiOCl/layered bimetallic oxide heterojunction for enhanced photocatalytic degradation of bisphenol A

Constructing heterogeneous photocatalysts to enhance the visible light absorption and photo-generated charge carrier separation for efficient degradation of organic pollutants in water samples remained a significant challenge. An S-scheme BiOCl/ZnCrZr-layered bimetallic oxide (LBMO) heterojunction was constructed by depositing BiOCl nanoparticles on ZnCrZr-LBMO. The characterization of material samples were by XRD, SEM, TEM, XPS, FTIR, UV–Vis-DRS, transient photocurrent response, and electrochemical impedance spectroscopy. The photocatalytic efficiency of BiOCl/ZnCrZr-LBMO heterojunction was obviously improved, about 3.95 and 1.68 folds higher than that of pristine BiOCl and ZnCrZr-LBMO, respectively. The fast separation and migration and the prolonged lifetime of photo-generated carriers in the BiOCl/ZnCrZr-LBMO heterojunction were validated by photoelectrochemical tests. The influence factors, versatility, and reusability of the heterojunction were also evaluated. Free radical scavenging test and ESR experiment revealed that ·O2– and h+ active radicals were the dominant active radicals in the BPA degradation. Additionally, BPA degradation intermediates were detected by LC-MS, and the possible degradation pathway of BPA was deduced using density functional theory. This novel S-scheme model heterojunction was expected to provide new ideas for the study of the photocatalytic mechanism and the BPA removal.

Photocatalytic activity of dual defect modified graphitic carbon nitride is robust to tautomerism: machine learning assisted ab initio quantum dynamics.

Two-dimensional graphitic carbon nitride (GCN) is a popular metal-free polymer for sustainable energy applications due to its unique structure and semiconductor properties. Dopants and defects are used to tune GCN, and dual defect modified GCN exhibits superior properties and enhanced photocatalytic efficiency in comparison to pristine or single defect GCN. We employ a multistep approach combining time-dependent density functional theory and nonadiabatic molecular dynamics (NAMD) with machine learning (ML) to investigate coupled structural and electronic dynamics in GCN over a nanosecond timescale, comparable to and exceeding the lifetimes of photo-generated charge carriers and photocatalytic events. Although frequent hydrogen hopping transitions occur among four tautomeric structures, the electron-hole separation and recombination processes are only weakly sensitive to the tautomerism. The charge separated state survives for about 10 ps, sufficiently long to enable photocatalysis. The employed ML-NAMD methodology provides insights into rare events that can influence excited state dynamics in the condensed phase and nanoscale materials and extends NAMD simulations from pico- to nanoseconds. The ab initio quantum dynamics simulation provides a detailed atomistic mechanism of photoinduced evolution of charge carriers in GCN and rationalizes how GCN remains photo-catalytically active despite its multiple isomeric and tautomeric forms.

Integrating ultraviolet sensing and memory functions in gallium nitride-based optoelectronic devices.

Optoelectronic devices present a promising avenue for emulating the human visual system. However, existing devices struggle to maintain optical image information after removing external stimuli, preventing the integration of image perception and memory. The development of optoelectronic memory devices offers a feasible solution to bridge this gap. Simultaneously, the artificial vision for perceiving and storing ultraviolet (UV) images is particularly important because UV light carries information imperceptible to the naked eye. This study introduces a multi-level UV optoelectronic memory based on gallium nitride (GaN), seamlessly integrating UV sensing and memory functions within a single device. The embedded SiO2 side-gates around source and drain regions effectively extend the lifetime of photo-generated carriers, enabling dual-mode storage of UV signals in terms of threshold voltage and ON-state current. The optoelectronic memory demonstrates excellent robustness with the retention time exceeding 4 × 104 s and programming/erasing cycles surpassing 1 × 105. Adjusting the gate voltage achieves five distinct storage states, each characterized by excellent retention, and efficiently modulates erasure times for rapid erasure. Furthermore, the integration of the GaN optoelectronic memory array successfully captures and stably stores specific UV images for over 7 days. The study marks a significant stride in optoelectronic memories, showcasing their potential in applications requiring prolonged retention.

Porphyrin-Based Two-Dimensional Metal-Organic framework nanosheets for efficient photocatalytic CO2 transformation

2D metal − organic framework (MOF) nanosheets have been demonstrated to exhibit excellent properties and prospects in various aspects, especially in photocatalysis. However, the design and direct preparation of 2D MOF photocatalyst is highly desirable but still challenging. Herein, a novel 2D porphyrin-based MOF Fe-DBP(Co), which is assembled by dicarboxylic porphyrin ligands and the unprecedented undecametallic ferric-oxo clusters, is designed and developed. The unique nanosheet morphology and assembled layered structure endows the photocatalyst with higher electron-hole separation efficiency and longer photogenerated carrier lifetime compared to the analogous MOFs. Consequently, Fe-DBP(Co) exhibits strikingly excellent and stable photocatalytic performance in CO2 cycloaddition, and the reaction rate of 103.2 mmol∙g−1∙h−1 is among the state-of-the-art cases for MOF-photocatalyzed CO2 cycloaddition. The underlying mechanism investigation suggested that photogenerated electrons transferred from CoDBP ligands to the Fe clusters, and the abundant electrons and holes promoted the generation of Fe(II) and Co(III) respectively, leading to excellent catalytic performance. This work proposes a new strategy to design and develop efficient MOF photocatalysts for photocatalytic transformation of CO2.

Ultraviolet photo-memory with image storage functions by controlling carriers’ lifetime

Ultraviolet (UV) photodetectors (PDs) have been widely developed for multifunctional applications such as flame detection, space communication and missile detection etc. However, limited attention has been paid to developing UV PDs with photo-memory capabilities, despite their enormous potential for applications in the field of imitating human learning and memory. In this work, we propose a ZnS/ZnO/ZnS heterojunction for UV optoelectronic synapse with optoelectronic memory functions. Through the incorporation of a ZnS shell layer, we achieved a substantial enhancement in the near-band photoluminescence of ZnO and a marked improvement in the lifetime of photo-generated carriers. The ZnS/ZnO/ZnS-3 h UV PD demonstrate a responsivity of 3.6 A/W (5 V bias 0.28 mW/cm2 365 nm light.), which is 12 times of that of ZnO UV PD (0.3 A/W). Additionally, by controlling the thickness of ZnS shell, we extend the decay time of ZnS/ZnO/ZnS-3 h UV PD from 95 s (ZnO) to 378 s, indicating its potential for UV image storage. Also, it shows versatile synaptic functions, including photonic potentiation, paired-pulse facilitation, short-/long-term memory, as well as a “learning” behavior. These results show that UV PDs with long decay time have new potential applications in UV image storage.

Passivation of CdTe/MgCdTe double heterostructure by dielectric thin films deposited using atomic layer deposition

This work reports a study of the passivation effects of different dielectric thin films deposited on monocrystalline CdTe/MgCdTe double heterostructures (DHs) using atomic layer deposition (ALD). Enhanced photoluminescence intensity was observed in all DHs with surface passivation, and increased photogenerated carrier lifetime was observed in DHs with HfO2, TiO2, Al2O3, and TiN passivated CdTe/MgCdTe DHs. These results have demonstrated effective suppression of the undesired surface recombination of CdTe/MgCdTe DHs by dielectric thin films deposited via ALD.

Construction of S-Scheme Co2SnO4/graphdiyne heterojunction to promote carrier transfer for efficiently photocatalytic hydrogen evolution characterized with in situ XPS

Graphdiyne (g-CnH2n-2), a novel two-dimensional carbon isomeric material consisting of a network of sp and sp2 co-hybridized hybridized carbons, has been highly regarded for its excellent chemical and physical properties and unique structure since it was first synthesized in 2010. However, as a photocatalyst, its application in the field of hydrogen production is still rare, which is a good opportunity for the field of photochemical catalyze hydrogen production. In this work, a binary catalyst Co2SnO4/graphdiyne was constructed by calcining graphdiyne and CoSn(OH)6 together after grinding. The structure of high-temperature calcination closely linked Co2SnO4 and graphdiyne, which led to an increased contact area and more active sites with faster photogenerated electron transfer efficiency. Therefore, Co2SnO4/graphdiyne showed good photocatalytic hydrogen production efficiency. Under the optimum amount of EY the hydrogen production rate reached 8.79 mmol g−1 h−1, which was 80.11 and 33.70 times higher than that of Co2SnO4 and graphdiyne, respectively. The construction of Co2SnO4/graphdiyne S-scheme heterojunction proved by in-situ XPS, EPR (DMPO-•O2−) experiment and the hydroxyl radical detection experiment retains high redox potential and prolongs the lifetime of photo-generated carriers. The catalyst preparation method in this work is innovative, which provides a general and high-efficiency strategy for applying the graphdiyne-based S-scheme heterojunction photocatalyst to solar energy-hydrogen energy conversion for photocatalytic water decomposition into hydrogen.

Significant sensitivity enhancement of single crystal CdSe x-ray detector by liquid nitrogen cooling

Owing to the large x-ray attenuation coefficient, appropriate bandgap, high resistivity, and high mobility-lifetime (μτ) product, binary II–VI semiconductor CdSe is a promising x-ray detection material and it has exhibited excellent x-ray detection at room temperature (RT). For further improving the characteristics of CdSe x-ray detectors, the electrical properties of CdSe single crystals (SCs) grown through the pressure-assisted vertical Bridgman method and their x-ray detection performance have been investigated at RT and liquid nitrogen temperature (LNT), respectively. The significantly enhanced x-ray photocurrent and the prolonged response time of the devices operating at LNT indicate the photogenerated carrier lifetime could be increased by the enhanced trapping–detrapping effect obviously, and the μτ product of CdSe SCs increases from 1.39 × 10−5 to 5.34 × 10−4 cm2 V−1 with temperature lowering from RT to LNT. Meanwhile, an ultrahigh sensitivity of 5.24 × 106μC Gyair−1 cm−2 and an extremely low detection limit of 3.68 nGyair s−1 have been acquired by the CdSe SC based x-ray detectors at LNT, which is 140 times higher and 5.8 times lower than it has been at RT. Compared with conventional semiconductor x-ray detectors, the ultra-high sensitivity and extremely low detection limit of CdSe SC based detectors make their application prospects very promising.

Co-passivation of perovskite film towards stable and efficient perovskite solar cell

Inverted perovskite solar cells (PSCs) have attracted tremendous attention due to their compatibility in flexible and tandem devices, thus with great commercialization potential. However, abundant crystal defects and energy level mismatch still remain throughout the devices, which cause nonradiative recombination and become the two main issues impeding the performance that need to be solved urgently. In this work, we have adopted a co-passivation strategy by incorporating PEACl (phenethylammonium chloride) into perovskite films and adding PPF (2,8-Bis(diphenyl-phosphoryl)-dibenzo[b,d]furan) in anti-solvent. It is found that PEACl could significantly passivate the defects in the perovskite bulk and grain boundaries. PPF could reinforce the passivation efficacy by forming coordination bond between PPF and Pb2+ (P=O→Pb). It also forms a thin n-type hole-blocking layer between perovskite film and electron transport layer, which increases photo-generated charge carrier lifetimes and decreases nonradiative recombination at carrier transport interfaces. Furthermore, after being co-passivated with PEACl and PPF (PEACl/PPF treated), an energy level gradient is formed between the perovskite and passivated layer, which is conducive to electron extraction and hole blocking, further resulting in less energy loss in the charge transfer process. As a result, the PEACl/PPF treated device obtained a power conversion efficiency (PCE) of 22.70% with an impressive open-circuit voltage (Voc) of 1.19 V, much higher than the corresponding values (19.51% and 1.06 V) of the control device.

Photoexcitation induced magnetic phase transition and spin dynamics in antiferromagnetic MnPS3 monolayer

Antiferromagnetic spin dynamics is the key issue to develop spintronic devices. We adopt ab initio nonadiabatic molecular dynamics with spin–orbit-coupling (SOC) to investigate photoinduced spin dynamics in an antiferromagnetic semiconductor MnPS3 monolayer. Optical doping triggers MnPS3 from Néel antiferromagnetic to ferromagnetic phase at an experimentally achievable electron–hole pair density of 1.11 × 1014 cm−2. This phase transition can be ascribed to the light-induced mid-gap states of S-p orbitals, which lower the electron excitation energy and strengthen the SOC effect between S-p and Mn-d orbitals. The excited S-p electrons first decay to the mid-gap states due to p–p electron–phonon-coupling and then relax to the spin-down Mn-d orbitals via SOC. Such a dramatic relaxation process prolongs the photogenerated carrier lifetime up to 648 fs, providing an explanation for the unusual optoelectronic performance of MnPS3. The reversible switching of magnetic order via optical means gives an important clue for information storage and highly efficient photocatalysts utilizing antiferromagnetic semiconductors.

The construction of lattice-matched CdS-Ag2S heterojunction photocatalysts: High-intensity built-in electric field effectively boosts bulk-charge separation efficiency

The built-in electric field of heterojunction can effectively promote carrier separation and transfer. While, its interface orientation is often random, leading to lattice mismatch and high resistance, thus limiting the efficiency of interfacial charge transfer. Herein, the lattice-matched heterojunction (CdS-Ag2S) was constructed by ion-exchange epitaxial growth. The results of surface photovoltage spectroscopy (SPV), transient photovoltage spectroscopy (TPV), and time-resolved photoluminescence (TRPL) show that the lattice-matched heterojunction has higher charge separation efficiency and longer photogenerated carrier lifetime than that of lattice-mismatched one. The lattice-matched CdS-Ag2S has a high built-in electric field (BIEF) value of 103.42 and a bulk-charge separation (BCS) efficiency of 68.71%, which is about three times higher than that of the lattice-mismatched heterojunction (CdS-Ag2S-M). In addition, the photodegradation efficiency of CdS-Ag2S towards norfloxacin (NOR) was also 3.4 times higher than that of CdS-Ag2S-M. The above results and density functional theory (DFT) calculations indicate that improving the lattice matching at the heterojunction is beneficial for establishing a high-intensity built-in electric field and effectively promoting bulk-charge separation efficiency, thus achieving excellent photocatalytic performance. This work provides an essential reference for the research of high-performance heterojunction photocatalysts.

Enhanced photocatalytic Cr(Ⅵ) reduction over the Z-scheme ZnO/ZnIn2S4 composite under visible light

In the present study, a series of ZnO/ZnIn2S4 photocatalysts with different mass ratios were synthesized for Cr(VI) removal. The surface morphology and chemical composition analysis results showed a well-distributed presence of ZnO nanoparticles on the surface of ZnIn2S4 with self-assembled microporous or mesoporous flower-like structure. The Mott−Schottky diagram indicated compatibility between the band structures of ZnO and ZnIn2S4. Moreover, the maximum Cr(VI) removal efficiency was achieved with 5% ZnO/ZnIn2S4 at pH 4.0, 1.6-fold and 14.5-fold higher than pristine ZnIn2S4 and ZnO, respectively. The pseudo-first-order kinetic model effectively simulated the Cr(VI) removal by ZnO/ZnIn2S4. The enhanced performance of ZnO/ZnIn2S4 was mainly attributed to the interaction between ZnO and ZnIn2S4, resulting in a Z-scheme heterojunction that improved visible-light absorption and charges separation efficiency. Fourier transform infrared and X-ray photoelectron spectroscopy indicated a partial reduction of Cr(VI) to Cr(III). At the same time, TR-PL tests demonstrated longer showed that the photogenerated carrier lifetimes in the compared heterojunction materials were higher than those of ZnO and ZnIn2S4. Free radical capture and electron paramagnetic resonance (EPR) experiments further confirmed that photogenerated electrons (e−) and superoxide radicals (·O2−) were the primary active species in the photoreduction of Cr(VI). These results highlight the potential of ZnO/ZnIn2S4 Z-scheme heterojunction as an efficient photocatalyst for wastewater treatment under visible light irradiation.

ZnSe nanoflakes/ ZnO quantum dots heterojunction-based bandgap engineered, flexible broadband photodetector on paper substrate

ZnO-based photodetectors exhibit high responsivity and high photon absorption coefficients. However, they show absorption in a narrow range and a low photogenerated carrier lifetime, limiting their potential applications in optoelectronics. This work demonstrates a high-performance broadband photodetector using Zinc Selenide nanoflakes (ZnSe) - Zinc Oxide (ZnO) quantum dots (QDs) heterojunction. Using a simple hydrothermal method on a flexible paper substrate, this work overcomes the complexity of previously reported fabrication techniques that involve electrospinning, electron beam lithography, spin coating, etc. Detailed chemical and structural characterization reveal the formation of cubic phase of ZnSe nanoflakes-like structure showing broad absorption in the visible region. In contrast, ZnO QDs show a hexagonal structure and absorption in the ultraviolet region, improving the photodetector's detection range. The device shows superior responsivity (Rʎ) of 17.2 µA/W, and 30 µA/W, with specific detectivity (D*) of 4.74×107 Jones, and 9.39×107 Jones, for ultraviolet, and visible, respectively. Detailed studies based on energy band diagrams are performed to understand the charge transport mechanism. The device shows excellent reliability and high stability for 500 bending cycles, thus, presenting a low-cost, facile approach for developing high-performance photodetectors that find utility in wearables, healthcare, and security/defense applications.

Insight into the Molecular Mechanism for Enhanced Longevity of Supramolecular Vesicular Photocatalysts.

Supramolecular self-assembly is a promising strategy for stabilizing the photo-sensitive components in photocatalysis. However, the underlying correlation between the enhanced photostability and supramolecular structure at the molecular level has not yet been fully understood. Herein, we develop a biomimetic vesicular membrane-based polyporphyrin photocatalyst exhibiting excellent photocatalytic stability with at least activity time of 240 h in hydrogen generation. Time-domain ab Initio modelling together with transient absorption spectroscopy, visual frontier orbitals and Gibbs free energy calculation disclose that the ordered aggregation of porphyrin units in the vesicle membrane facilitates "hot" electron relaxation, a longer photo-generated carrier lifetime and the rapid dissipation of photo-generated charges, which contribute to the longevity. This work deepens the molecular-level understanding on photostability and photocatalytic mechanism of supramolecular photocatalysts.