Light Illumination Research Articles

Single-atom Cu sites on covalent organic frameworks with Kagome lattices for visible-light-driven CO2 reduction to propylene

CO2 to multicarbon fuels via photocatalytic conversion, especially propylene, is a viable pathway, but propylene remains unreported due to the two C-C coupling with the eighteen-electron reduction process. Herein, [1,1′-biphenyl]-3,3′,5,5′-tetracarbaldehyde, and [2,2-bipyridine]-5,5-diamine units were condensed and synthesized in combination with a post-modification strategy, named BTA-COF-M (M = H, Cu, Fe, Co, Ni or Zn). BTA-COF-Cu has distinct kagome lattices and abundant exposed-atom Cu sites, which can induce CO2 to undergo two C-C couplings into C3H6 products under visible light illumination. According to experimental and theoretical analyses, the outstanding performance of BTA-COF-Cu can be attributed to the ideal synergistic contribution of the Kagome lattices and the atomic Cu active sites, which promote CO2 adsorption/activation, facilitate photoexcited charge carrier dynamics, and induce secondary coupling of key intermediates. This research provides an innovative perspective for the construction of Kagome lattice COF with monatomic metal sites for CO2 reduction to high value-added propylene.

The negative differential resistance of nitrogen implanted TiO2

The microstructure and negative differential resistance (NDR) effect of nitrogen implanted rutile TiO2 were investigated by measuring the XPS, Raman spectra and current voltage curves. It was found that the light illumination has large influence on the NDR effect. Under the illumination of 60 mW laser light, a large NDR with a small electric field (1250 V/cm) is obtained. This electric field is about three orders smaller than that reported in literature (1×106 V/cm). The electric field induced tunneling is the possible mechanism of electric transport at higher field region. The NDR is thought to be related to the light and nitrogen dopant induced reaction including the destroying of water, the scavenging of electron, and the surface oxidation transform of non-stoichiometric TiO2−x to stoichiometric insulating state. The results of this paper are not only useful in understanding the mechanism of NDR, but also useful in providing an effective method in manipulation NDR.

Preferentially coordinating tin ions to suppress composition segregation for high-performance tin-lead mixed perovskite solar cells

Tin-lead mixed perovskites (TLPs) with a tunable and ideal bandgap exhibit great potential in approaching the Shockley–Queisser limit of power conversion efficiency (PCE). However, two critical issues are necessary to be addressed, including the oxidation of Sn2+ and negligible composition and phase segregation. The latter derives from the unbalanced crystallization rate between Sn- and Pb-based perovskites. Here, we report a strategy to address the above critical issues by introducing 3,4-Dihydroxybenzylamine hydrobromide (DHBABr) in the TLP precursor solution. DHBABr was revealed to promote the crystallization of FAPbI3 perovskite by suppressing the formation of crystalline DMSO-FA-Pb-I intermediates and retard the crystallization rate of FASnI3 by preferentially forming a steady amorphous DHBA-FA-Sn-I intermediate. This, therefore, balances the crystallization rate between Sn- and Pb-based perovskites. As a result, the spatial distribution of Sn/Pb ratio is much more uniform across the whole TLP film, which benefits the upscaling of the manufacturing process. Relying on this doping strategy accompanied by the surface passivation with DHBABr, which reduces the defect density of TLP, inhibits the oxidation of Sn2+, and optimizes the band alignment of the device, we have achieved a PCE of 22.44 % with Voc of 0.853 V and FF of 80.0 %, along with an enhanced long-term stability of T80 = 476 h under continuously light illumination in the champion device.

Characterization of bulk trap density using fully I–V-based optoelectronic differential ideality factor in multi-layer MoS2 FETs

Abstract Molybdenum disulfide (MoS2) has excellent optoelectronic properties, chemical stability, and a two-dimensional (2D) structure, making MoS2 a very versatile field-effect device material. Herein, we characterize MoS2 and utilize a photo-responsive I–V technique for extracting the energy distribution of the bulk traps in multi-layer MoS2 field effect transistors (FET). This method uses the differential ideality factor in both dark and light conditions. The differential ideality factor enables the efficient quantitative extraction of the device trap density by considering the nonlinear characteristics of the subthreshold region (V ON < V GS < V T). To accurately differentiate between the sub-bandgap traps and the interface traps near the conduction band, near-infrared light (λ= 1530 nm) optical illumination was used for the light state characterization. The bulk trap densities under dark state and light state conditions were derived for multi-layer (7-layer and 9-layer) MoS2 FET channels, and the influence of light illumination and overall multi-layer thickness on the bulk trap density was confirmed. The accurate extraction of the trap density enables the design of MoS2 FETs with long-term stability and high optoelectronic performance.

Facile synthesis of Co-doped In2O3 integrated with tubular g-C3N4 heterostructure and their synergistic effect on the enhanced photocatalytic degradation of tetracycline and oxygen evolution reaction

In this work, we developed cost-effective and environmentally friendly bifunctional catalysts for energy and environmental applications. Tubular graphitic carbon nitrides (TCN), In2O3, In2O3/TCN, and x% cobalt (Co) doped In2O3/TCN (x = 1 %, 3 %, and 5 wt% of Co) composite materials synthesized by polymerization and hydrothermal methods. The photocatalytic activity of these materials was tested for tetracycline (TC) removal under sunlight and visible light illumination. Among them, 5 % Co-In2O3/TCN composite exhibited the highest photocatalytic efficiency, achieving 100 % and 94 % TC degradation under sunlight and visible light, respectively. PL analysis indicated that the 5 % Co-In2O3/TCN composite exhibited superior charge separation efficiency. Scavenging tests confirmed that holes (h+) and superoxide radicals (O2•−) play important roles in the photocatalytic process. The electrochemical performance of the prepared materials was investigated in 1.0 M KOH. Among the catalysts, the 5 % Co-In2O3/TCN@nickel foam (NF) composite showed the best oxygen evolution reaction (OER) performance with low overpotential (240 mV) and Tafel slope (95 mV/dec) and maintained stability for more than 24 h at 10 mA/cm2. An electrolyzer using 5 % Co-In2O3/TCN@NF||Pt/C@NF catalyst achieved cell voltages of 1.73 V and 2.23 V at 10 mA/cm² and 100 mA/cm², respectively. In this study, we developed low-cost photo and electrocatalysts that exhibited excellent environmental remediation and energy production capabilities.

Rational design of Boerhavia diffusa derived CoFe2O4-Carbon dots@Boehmite platform for photocatalysis and ultra trace monitoring of hazardous pesticide and UO22+ ions

In view of exploiting natural resources for designing of effectual materials in favor of detection and obliteration of water pollutants, a fluorescent nanomaterial (CDBHCF) based on biomass derived carbon dots (CDs) was constructed. The CDs and cobalt ferrite (CF) particles were anchored on boehmite (BH) which served as a support material for CDs. The CDBHCF nanocomposite was prepared via facile hydrothermal treatment for selective recognition of Methyl parathion (MP) pesticide and uranyl ions (UO22+). The corresponding structural, morphological and opto-electronic properties of the nanomaterials have been investigated by different physicochemical techniques. The fluorescent CDBHCF probe was employed to detect extremely low concentration of MP and UO22+ with detection limit of 22.4 nM and 4.4 nM, respectively. Ultimately, the proposed sensing platform was validated through real sample analysis. Besides, CDBHCF nanocomposite was utilized for photocatalytic abolition of Tetracycline (TC) in water samples. Initially, the impact of various operational parameters on the degradation efficiency, including catalyst dosage and initial pH were thoroughly examined. Under optimized conditions, the fabricated CDBHCF nanocomposite demonstrated excellent results for photocatalytic degradation of TC (92 % degradation in 120 min) under visible light illumination. Thus, the proposed strategy delivered an innovative insight for dual purpose of CDBHCF nanocomposite: as a fluorescent probe for real time monitoring and as a photocatalyst for removal of pollutants via simple photocatalytic degradation.

Super-Resolution Microscopic Imaging of Lipid Droplets in Living Cells via Carbonized Polymer Dot-Based Polarity-Responsive Nanoprobe.

Lipid droplets (LDs) are dynamic subcellular organelles that participate in various physiological processes, and their abnormality can also lead to various diseases. Tracing the dynamics of LDs in living cells will be valuable for understanding cell physiological states. Here, we employed a structured light illumination super-resolution imaging assisted with a carbonized polymer dot (CPD)-based fluorescence nanoprobe to track the travel paths of LDs and other organelles. The CPDs we developed are highly biocompatible with living cells and exhibit a highly sensitive response to solvent polarity, allowing for high specificity in staining LDs in living cells. Aided by these nanoprobes, we successfully observed many real-time LD-involved dynamics in living cells, such as intracellular LD interactions, communications with other organelles, and dynamic behaviors under external stimuli (oxidative stress inducer). These studies deepen our comprehension of the physiological role of LDs and drive the advancement of super-resolution fluorescent probes.

Far-Field Phase-Shifting Structured Light Illumination Enabled by Polarization Multiplexing Metasurface for Super-Resolution Imaging.

The phase-shifting structured light illumination technique is widely used in imaging but often relies on mechanical translation stages or spatial light modulators, leading to system instability, low displacement accuracy, and limited integration feasibility. In response to these challenges, we propose and demonstrate an approach for generating far-field phase-shifting structured light using a polarization multiplexing metasurface. By controlling the polarization states of incident and transmitted light, the metasurface creates a three-step displacement of structured light, eliminating the need to move samples or illumination sources. As a proof of concept, we experimentally demonstrate microscopic imaging using structured light illumination generated by metasurfaces, extracting high-frequency information from objects, and surpassing the diffraction limit. The proposed metasurface platform offers a promising approach for developing compact and robust phase-shifting imaging systems, with broad prospects in quantitative detection, machine vision, and beyond.

Photocatalytic Reforming of Ethanol in the Liquid Phase Using a Ternary Composite of Rh/TiO2/g-C3N4 as a Catalyst.

Photocatalytic reforming of ethanol provides an effective way to produce hydrogen energy using natural and nontoxic ethanol as raw material. Developing highly efficient catalysts is central to this field. Although traditional semiconductor/metal heterostructures (e.g., Rh/TiO2) can result in relatively high catalyst performance by promoting the separation of photoinduced hot carriers, it will still be highly promising to further improve the catalytic performance via a cost-effective and convenient method. In this study, we developed a highly efficient photocatalyst for ethanol reformation by preparing a ternary composite structure of Rh/TiO2/g-C3N4. Hydrogen is the main product, and the reaction rate could reach up to 27.5 mmol g-1 h-1, which is ∼1.41-fold higher than that of Rh/TiO2. The catalytic performance here is highly dependent on the wavelength of the light illumination. Moreover, the photocatalytic reforming of ethanol and production of hydrogen were also dependent on the Rh loading and g-C3N4:TiO2 ratio in Rh/TiO2/g-C3N4 composites as well as the ethanol content in the reaction system. The mechanism of the enhanced hydrogen production in Rh/TiO2/g-C3N4 is determined as the improvement in the separation of photoinduced hot carriers. This work provides an effective photocatalyst for ethanol reforming, largely expanding its application in the field of renewable energy and interface science.

Impact of Light on Coexistence of Memresistance, Meminductance, and Memcapacitance (MEMRIC) in Nanostructured Copper Oxide (CuO) based Random Access Memory Devices.

We demonstrated the coexistence of memresistance, memcapacitance, and meminductance non-volatile bipolar analog resistive switching in Cu (top electrode)/CuO (active layer)/ SS (bottom electrode) memory devices with and without the presence of the light. The onset of memcapacitance and meminductance is noticed from the pinched-shaped characteristics in the first and third quadrants. The variation in the scan rate also impacts the coexistence characteristics by shifting the intercept point for low resistance (LRS) and high resistance (HRS) states in positive and negative biasing voltages. The durability and retention are measured over a period of 150 cycles and 1500 s with and without light illumination. The Weibull slope for set/reset state with and without light are 106.80/114.23 and 70.21/102.25, respectively, suggesting that stability of the device increases with light illumination. Interestingly, the memcapacitance disappears after 600 cycle and after 60 . The double logarithmic I-V characteristics suggest the trap assisted conduction (higher slope > 2) in the higher external electric field, and Ohmic behaviour in the lower applied field region. Thus, the present study provides a way for low power electronics and photoresistors together with memresistance, memcapacitance, and meminductance, simultaneously, i.e., MEMRIC in a single device.

Near-infrared-responsive sea-urchin-like Ag6Si2O7/Bi19Br3S27 S-scheme heterojunction for efficient CO2 photoreduction

The construction of S-scheme heterojunctions effectively facilitates the spatial separation of photogenerated charge carriers for their involvement in photoreactions. However, the inefficient utilization of solar energy in these heterostructures is often due to unfavorable band-edge positions and suboptimal charge transport dynamics, which result in low photocatalytic efficiency when considering kinetic factors. In this study, sea urchin–like Bi19Br3S27/Ag6Si2O7 S-scheme heterojunctions are fabricated, which exhibit excellent CO2 photoreduction performance under ultraviolet, visible, and near-infrared (NIR) light illumination. Experimental data and density functional theory calculations confirm the S-scheme charge transfer mechanisms, which enable the efficient separation of photogenerated carriers for CO2 reduction. Consequently, the optimized Ag6Si2O7/Bi19Br3S27 heterostructures exhibit superior CO2 photoreduction activity under NIR light irradiation. This approach offers a strategy for designing advanced NIR-light-responsive photocatalysts for efficient CO2 photoreduction.

Optogenetic control of early embryos labeling using photoactivatable Cre recombinase 3.0.

Establishing a highly efficient photoactivatable Cre recombinase PA-Cre3.0 can allow spatiotemporal control of Cre recombinase activity. This technique may help to elucidate cell lineages, as well as facilitate gene and cell function analysis during development. This study examined the blue light-mediated optical regulation of Cre-loxP recombination using PA-Cre3.0 transgenic early mouse pre-implantation embryos. We found that inducing PA-Cre3.0 expression in the heterozygous state did not show detectable recombination activation with blue light. Conversely, in homozygous embryos, DNA recombination by PA-Cre3.0 was successfully induced by blue light and resulted in the activation of the red fluorescent protein reporter gene, while almost no leaks of Cre recombination activity were detected in embryos without light illumination. Thus, we characterize the conditions under which the PA-Cre3.0 system functions efficiently in early mouse embryos. These results are expected to provide a new optogenetic tool for certain biological studies, such as developmental process analysis and lineage tracing in early mouse embryos.

Columnar Macrocyclic Molecule Tailored Grain Cage to Stabilize Inorganic Perovskite Solar Cells with Suppressed Halide Segregation

AbstractSolidifying the soft lattice of all‐inorganic mixed‐halide perovskites is of great importance to restrain the notorious halide segregation under persistent light illumination. Herein, a multifunctional columnar macrocyclic molecule additive, namely cucurbituril into perovskite precursor to enhance the crystallization and reduce the defect density in the final perovskite film is introduced. Based on the theoretical calculation and simulation, the cucurbituril molecule with a strong double‐ended negatively‐charged cavity surrounded by terminated oxygen atoms not only coordinates with dangling Pb2+ ions to form host‐guest complexation but also induces an electric dipole field at perovskite grain boundary to effectively repel the iodide ion migration from the inside grain to the defective boundary, significantly suppressing the halide segregation and improving the device performance. As a result, the carbon‐based, all‐inorganic CsPbI2Br solar cell achieves an enhanced efficiency of 15.59% with great tolerance to environmental stresses. These findings provide new insights into the development of a novel passivation strategy with macrocyclic molecules for making high‐efficiency and stable perovskite solar cells.

Construction of ZnAl LDH-Derived Sulfides with Etching Modification to Trigger Photocatalytic H2 Production and Degradation Oxidation.

Constructing novel functional photocatalysts represents a promising approach to optimize the energy band structure and facilitate the separation of photogenerated carriers. Layered double hydroxides (LDHs) exhibit notable advantages in photocatalysis due to the exceptional photoelectrochemical properties and elevated number of active surface atoms. However, an unsuitable band gap and limited carrier migration have inhibited their development in photocatalysis. Herein, we propose a novel in situ topological vulcanization strategy for optimizing the photocatalytic activity of ZnAl LDH-derived sulfides (ZnAlSx). The subsequent etching process via a 1 M NaOH solution was introduced to construct the ZnSx photocatalysts. Then, the crystallinity of the crystals was enhanced by etching to further improve the catalytic activity and stability of ZnSx. The as-synthesized ZnSx shows an excellent photocatalytic hydrogen production rate (11.89 mmol/g/h) and tetracycline degradation efficiency (91.94%) under light illumination, and its hydrogen evolution efficiency is approximately 176 and 2 times greater than that of ZnAl LDH and ZnAlSx, respectively. The characterization and density functional theory (DFT) analysis confirmed that the surface electronic properties and energy band structure of ZnAl LDH were significantly optimized after experimental treatment, resulting in enhanced carrier separation and photooxidative reduction capacity. Combining in situ topological vulcanization and etching to realize the functional conversion of ZnAl LDH provides promising insights into the construction of high-performance, low-cost photocatalysts.

Bio‐p–n Junction–Derived Bio–Diodes With Opto‐Ionotronic Switching and Rectification Effects

AbstractThe advancement of bio‐ionotronics for the brain‐computer interaction necessitates an exploration of the mechanisms of electron‐ion coupled transport in solid state devices. In this study, a bio‐p–n junction composed of n‐type bacteriorhodopsin and p‐type P3HT are proposed. By leveraging electron‐proton synergistic effects, an opto‐ionotronic bio‐diode capable of performing ionotronic switching and rectification functions is fabricated. The switching behavior of the bio‐diode can be controlled both optically and electrically. Under light illumination, the ionotronic bio‐diode exhibits a rectification effect approaching that of an ideal diode, with a reliability of 99% and a rectification ratio of ≈661. Additionally, this bio‐organic composite ionotronic bio‐diode exhibits wide pH responsiveness, good photostability, and high biocompatibility. The proposed opto‐ionotronic bio‐diode can be utilized as a fundamental component in logic circuits, bridging the gap between semiconductor technology and biological systems, and represents a novel paradigm for the advancement of brain‐computer interaction.

Developing a Multifunctional Cathode for Photoassisted Lithium-Sulfur Battery.

Integration of solar cell and secondary battery cannot only promote solar energy application but also improve the electrochemical performance of battery. Lithium-sulfur battery (LSB) is an ideal candidate for photoassisted batteries owing to its high theoretical capacity. Unfortunately, the researches related the combination of solar energy and LSB are relatively lacking. Herein, a freestanding photoelectrode is developed for photoassisted lithium-sulfur battery (PALSB) by constructing a heterogeneous structured Au@N-TiO2 on carbon cloths (Au@N-TiO2/CC), which combines multiple advantages. The Au@N-TiO2/CC photoelectrode can produce the photoelectrons to facilitate sulfur reduction during discharge process, while generating holes to accelerate sulfur evolution during charge process, improving the kinetics of electrochemical reactions. Meanwhile, Au@N-TiO2/CC can work as an electrocatalyst to promote the conversion of intermediate polysulfides during charge/discharge process, mitigating induced side reactions. Benefiting from the synergistic effect of electrocatalysis and photocatalysis, PALSB assembled with an Au@N-TiO2/CC photoelectrode obtains ultrahigh specific capacity, excellent rate performance, and outstanding cycling performance. What is more, the Au@N-TiO2/CC assembled PALSB can be directly charged under light illumination. This work not only expands the application of solar energy but also provides a new insight to develop advanced LSBs.

Fabrication of one-dimensional Zn-doped Bi2S3 nanorods for photodiode applications.

In this research, the impact of the different zinc (Zn) concentrations on the physical and optoelectronic properties of Bi2S3 nanorods as self-powered and photodiode applications was investigated. The performance of P-N junction photodiodes has been for decades since they are crucial in energy applications. The structure, degree of crystallinity, and shape of Zn-doped Bi2S3 nanorods of various doping percentages formed onto the indium tin oxide (ITO) substrates by the dip coating technique are investigated using X-ray powder diffraction (XRD) and SEM. With increasing illumination time, the current-voltage (I-V) graphs demonstrate a rise in photocurrent. The diode's idealist factor was estimated using the I-V technique under 30 min of light illumination.

Solvated Electrons Generated on the Surface of Na-SPHI for Boosting Visible Light Photocatalytic Hydrogen Evolution with Ultra-High AQE.

Enhancing the utilization of visible-light-active semiconductors with an excellent apparent quantum efficiency (AQE) remains a significant and challenging goal in the realm of photocatalytic water splitting. In this study, a fully condensed sulfur-doped poly(heptazine imide) metalized with Na (Na-SPHI) is synthesized by an ionothermal method by using eutectic NaCl/LiCl mixture as the ionic solvent. Comprehensive characterizations of the obtained Na-SPHI reveal several advantageous features, including heightened light absorption, facilitated exciton dissociation, and expedited charge transfer. More importantly, solvated electron, powerful reducing agents, can be generated on the surface of Na-SPHI upon irradiation with visible light. Benefiting from above advantage, the Na-SPHI exhibits an excellent H2 evolution rate of 571.8 µmol·h-1 under visible light illumination and a super-high AQE of 61.7% at 420nm. This research emphasizes the significance of the solvated electron on the surface of photocatalyst in overcoming the challenges associated with visible light-driven photocatalysis, showcasing its potential application in photocatalytic water splitting.

Visible light-triggered NIR ratiometric fluorescent metal-free CO-releasing molecule for self-monitoring of CO delivery and effective cancer therapy

Cancer is a serious global health issue, and exploring effective treatment methods is of great significance for cancer prevention and control. Carbon monoxide (CO), as an important gas signaling molecule in the life system, has been proven to have good anti-cancer effects. However, how to controllably, safely, and effectively deliver CO to the tumor site for clinical treatment remains a challenge. Herein, a new metal-free CO-releasing molecule COR-XAC was developed for controlling CO release and cancer therapy. COR-XAC is based on the hybrid of 3-hydroxyl flavone and oxanthracene fluorophores, showing visible light-controlled CO-releasing properties and near-infrared (NIR) ratiometric fluorescence changes at 690 and 760 nm. COR-XAC shows low cytotoxicity and can be successfully applied to release CO in cells and tumors, and the CO-releasing and delivery process could be monitored by its own NIR ratiometric fluorescence changes. More importantly, the anti-cancer performance of COR-XAC was evaluated in 4T1 tumor mice, and it was found that COR-XAC plus light illumination showed excellent tumor inhibition effect, which provided a promising new effective method for cancer treatment.

White afterglow achieved in Eu2+, Ce3+, Dy3+co-doped LiSr4(BO3)3 phosphor

In prior study by our team, orange-yellow afterglow was observed in Eu2+ and Dy3+ co-doped LiSr4(BO3 )3 phosphor due to the emission from Eu2+ center. In this study, further incorporation of Ce3+into the phosphor lead to the observation of white afterglow due to the mixed result of blue light from Ce3+ and orange-yellow light from Eu2+ centers. Upon ultraviolet excitation, the phosphor displays a spectrum characterized from blue emission of Ce3+ at 462nm and orange-yellow emission of Eu2+ at 632nm. Fine-tuning the concentration of Ce3+ enabled the realization of white luminescence in LiSr4(BO3)3: Eu2+, Ce3+ and Dy3+phosphor with chromaticity coordinates of (0.3979, 0.2939). The photoluminescence intensities of the samples could be modulated by incorporating varying amounts of Ce3+ ions, with a critical quenching concentration identified with 0.16 Ce3+. White afterglow is also observed after the removal of the light illumination due to the existence of suitable electron traps with optimal trap depth created by the co-doped Dy3+. The underlying mechanism proposes that the white afterglow is generated by the mixed lights of blue and orange-yellow that are created by the recombination of heat-released electrons from the trap centers with pre-existing holes in the Ce and Eu emission sites.