Enhanced Light Absorption Research Articles

All Organic Bulk Heterojunction Antibacterial Nanoparticles Prepared by Conjugated Donor Polymer and ITIC Acceptor

AbstractPFO‐DDQ is a donor−acceptor (D–A) type conjugated polymer, with its backbone consisting of 95% 9,9‐di‐octylfluorene (DOF) and 5% 2,3‐dimethyl‐5,8‐dithien‐2‐yl‐quinoxalines (DDQ). PFO‐DDQ nanoparticles (NPs) suspensions are prepared using the nanoprecipitation method by varying the precursor solution concentration. The photoluminescence (PL) spectrum of the nanoparticles is determined by the energy transfer between the fluorene and the narrow‐bandgap DDQ segments. The fluorescence of the NPs can be tuned from orange to blue by adjusting the concentration of the precursor solution. PFO‐DDQ, the nonfullerene acceptor small molecule (ITIC), and PFO‐DDQ/ITIC bulk heterojunction (BHJ) NPs suspensions are prepared using the nanoprecipitation method, and their photocatalytic antibacterial properties are evaluated. The results showed that, under 2 h of exposure to a 35 mW cm−2 LED light, the antimicrobial rates of the three 40 µg mL−1 nanoparticles suspensions against Escherichia coli (E. coli) are 98.28%, 100%, and 99.88%, respectively. The enhanced light absorption, improved charge transfer efficiency, and the crystalline phase of ITIC contributed to the faster photocatalytic antibacterial rate of PFO‐DDQ/ITIC BHJ nanoparticles.

Intermolecular Interactions Enhance the Light Absorption of a Methoxyphenol Constituent of Biomass Burning Emissions.

Brown carbon (BrC) components of biomass burning organic aerosol (BBOA) absorb sunlight at visible wavelengths. However, it is not clear whether the total light absorption of this BrC is simply the sum of the contributions of the individual components or whether the components can bind noncovalently to give additional absorption through charge transfer. Here, intermolecular interactions between guaiacol and quinones (1,4-benzoquinone and 1,4-naphthoquinone) were identified in proxies of the nonpolar, water-insoluble phase of BBOA, using UV-vis spectroscopy. Guaiacol and its derivatives are some of the most abundant emissions of smoldering coniferous species. Enhanced light absorption occurred instantaneously upon mixing colorless guaiacol with either quinone in n-heptane and did not increase with time, in contrast to the absorbance changes that would be expected for a covalent product. This enhancement decreased by about 25% as the temperature increased from 303 to 323 K, consistent with exothermic association to give complexes, yielding enthalpies of complexation of -13.3 ± 0.6 and -12.3 ± 0.4 kJ mol-1 for guaiacol with benzoquinone and naphthoquinone, respectively. Enhancement was also observed upon gas-liquid partitioning of benzoquinone into thin films of guaiacol, for example, with a thickness of 20 μm. This multiphase processing, mimicking partitioning of quinones into liquid BBOA, produced absorption comparable to moderately absorbing BrC from other sources, suggestive of the atmospheric relevance of these interactions.

A regulated TiO2@NC@ZCS photocatalyst for efficient hydrogen evolution: insights into the role of carbon layer positioning.

In this study, a TiO2@NC@ZCS ternary photocatalyst with a well-defined hexahedral morphology was synthesized via MOF-derived pyrolysis and sulfidation methods, and its photocatalytic hydrogen production performance was thoroughly investigated. The results demonstrated that the unique interface design of TiO2@NC@ZCS significantly enhanced light absorption, charge separation, and catalytic performance, achieving a remarkable hydrogen evolution rate of 10.244 mmol g-1 h-1. Comparative studies revealed that the precise placement of the carbon layer (NC) at the interface between TiO2 and ZCS was critical for efficient charge transfer and uniform distribution of active sites, whereas samples with NC coating the ZCS surface exhibited significantly reduced charge separation efficiency and catalytic activity.

Metal Oxide Nanoparticles Synthesized in Ionic Liquids: Characterization and Photodegradation of Methyl Orange.

Dye residues from the textile industry significantly contribute to water pollution, necessitating effective wastewater treatment methods. This study reports the successful synthesis of zinc oxide (ZnO) nanoparticles using various ionic liquids (ILs), [BMIM]-BF4, [BMIM]-PF6, and [BMIM]-Cl, as mediators. The synthesized nanomaterials were characterized using various techniques, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. Their photocatalytic activity in degrading methyl orange (MO) dye under UV-vis and sunlight irradiation was investigated. The results demonstrated that ILs significantly influenced the structural and optical properties of ZnO, resulting in smaller crystallite sizes, modified morphologies, and reduced band gap energies compared to unmodified ZnO. The ZnO-[BMIM]-BF4 (1%) exhibited superior photocatalytic efficiency, achieving complete MO degradation within 30 min under UV-vis irradiation, attributed to its enhanced light absorption and reduced electron-hole recombination. The ZnO-BMIM-PF6 (1%) demonstrated exceptional stability, maintaining high degradation efficiency over multiple cycles. These findings highlight the potential of IL-mediated synthesis in tailoring ZnO nanomaterials for efficient photocatalytic degradation of organic pollutants, offering a promising approach for wastewater treatment.

13.7 % Efficient Graphene/Si Heterojunction Solar Cells with One-Step Transferred Polymer Anti-Reflection Layer for Enhanced Light Absorption and Device Durability.

Graphene/Silicon (Gr/Si) heterojunction shows great potential as high-efficiency, cost-effective solar cells compared to traditional Si solar cells. However, the high optical loss of c-Si, mainly originating from abrupt change of refractive index at air/Si interface, and the unsatisfactory conductivity of practically prepared graphene layer, still hinder their extensive applications. Herein, we report the performance improved Gr/Si solar cells by depositing a polymathic methacrylate (PMMA) anti-reflection coating (ARC) layer through a one-step transferred method. The graphene and PMMA ARC with specific thickness were transferred on n-type Si wafer at the same time, which reduces production steps and obtains high-quality graphene layer. By tuning the thickness of the PMMA layer, the reflection can be reduced obviously. Companying with the HNO3 vapor doping for graphene, the Gr/Si heterojunction solar cell with a high power conversion efficiency (PCE) of 13.7 % was achieved. In addition, the durability of the device is improved under HNO3 doping. Considering the easy and cost-effective solution processed capability of the one-step transferred graphene and PMMA ARC layer, we believed that PMMA/Gr/Si is a feasible low-temperature technique for high-efficiency Si solar cells.

Insight into enhanced tetracycline photodegradation by hematite/biochar composites: Roles of charge transfer, biochar-derived dissolved organic matter and persistent free radicals.

Insight into enhanced tetracycline photodegradation by hematite/biochar composites: Roles of charge transfer, biochar-derived dissolved organic matter and persistent free radicals.

Bifunctional hierarchical WO3 nanorods@Br-doped g-C3N4 Z-scheme heterojunctions for efficient tetracycline photodegradation: Optimization of key parameters, toxicological assessment, and electrocatalytic hydrogen evolution reaction.

Bifunctional hierarchical WO3 nanorods@Br-doped g-C3N4 Z-scheme heterojunctions for efficient tetracycline photodegradation: Optimization of key parameters, toxicological assessment, and electrocatalytic hydrogen evolution reaction.

High-density superhard carbon stabilized by strain induced phase-transition and light absorption enhancement of its low-dimensional graphyne under high-pressure

High-density superhard carbon stabilized by strain induced phase-transition and light absorption enhancement of its low-dimensional graphyne under high-pressure

Type II ZnO-MoS2 Heterostructure-Based Self-Powered UV-MIR Ultra-Broadband p-n Photodetectors.

This study presents the fabrication and characterization of ZnO-MoS2 heterostructure-based ultra-broadband photodetectors capable of operating across the ultraviolet (UV) to mid-infrared (MIR) spectral range (365 nm-10 μm). The p-n heterojunction was synthesized via RF magnetron sputtering and spin coating, followed by annealing. Structural and optical analyses confirmed their enhanced light absorption, efficient charge separation, and strong built-in electric field. The photodetectors exhibited light-controlled hysteresis in their I-V characteristics, attributed to charge trapping and interfacial effects, which could enable applications in optical memory and neuromorphic computing. The devices operated self-powered, with a peak responsivity at 940 nm, which increased significantly under an applied bias. The response and recovery times were measured at approximately 100 ms, demonstrating their fast operation. Density functional theory (DFT) simulations confirmed the type II band alignment, with a tunable bandgap that was reduced to 0.20 eV with Mo vacancies, extending the detection range. The ZnO-MoS2 heterostructure's broad spectral response, fast operation, and defect-engineered bandgap tunability highlight its potential for imaging, environmental monitoring, and IoT sensing. This work provides a cost-effective strategy for developing high-performance, ultra-broadband, flexible photodetectors, paving the way for advancements in optoelectronics and sensing technologies.

Super Bending-Stable Flexible Colloidal QD Photodetector with Fast Response and Near-Unity Carrier Extraction Efficiency.

Flexible colloidal quantum dot (QD) optoelectronics apply the superior properties of colloidal QDs to flexible devices, exhibiting unique advantages in the fields of imagers, solar cells, displays, wearable sensors, on-skin electronics, robotics, and bioimaging. Here, we show that colloidal QD photodiodes (QDPDs) with an ultrathin QD absorber layer have record bending stability with 100,000 repetitive bending cycles in QD devices. The QDPDs obtained a high-quality p-n junction with a 1700 rectification ratio. The formation of a Fabry-Pérot cavity by the layered stack results in a 3.4-fold enhanced light absorption, while the ultrathin structure ensures a near-unity efficient extraction (97%) of photogenerated charge carriers from the PbS QD film upon illumination with 1330 nm short-wavelength infrared light. Finally, upon suppression of the capacitance effect, the response time of this QDPD can be as short as 20 ns, which is the fastest response for flexible colloidal QDPDs.

Preparation of core-shell-like Bi2WO6/BiOCl heterojunction with excellent visible-light photocatalytic activity

Constructing a ‘Z-scheme’ heterojunction is an effective method for improving photocatalyst activity. Core-shell-like Z-scheme bismuth tungstate (Bi2WO6)/bismuth oxychloride (BiOCl) heterojunction was synthesized through a two-step method. The arbutus-like bismuth oxychloride microsphere core was first gained by a solvothermal method. Then the Bi2WO6 nanosheet shell was in situ on the surface of the BiOCl microsphere through another solvothermal process. The bismuth tungstate/bismuth oxychloride heterojunction had a much better photocatalytic performance than that of the single bismuth tungstate, which was due to the enlarged BET surface area, enhanced light absorption, and photocarriers’ migration. The photocatalytic mechanism of the bismuth tungstate/bismuth oxychloride heterojunction was also proposed.

Fabry-Perot resonance cavity for ultra-thin GaAs negative electron affinity photocathodes

Electron accelerator and photodetector require negative electron affinity photocathode (NEA-PC) with high quantum efficiency (QE), short response time and low mean transverse energy (MTE). Finding a NEA-PC that simultaneously meets all these requirements is challenging. Here, a Fabry-Perot (F-P) cavity with a high reflective silver (Ag) mirror was used for GaAs NEA-PC, which was analyzed by a coupled Monte Carlo opto-electronic model. For the concerned wavelengths of 532 and 780 nm, enhanced light absorption peaks with Q-factor > 20 were obtained in a 100 nm ultra-thin GaAs NEA-PC layer by the standing wave resonance of the F-P cavity, which lead to the enhanced QE higher than that of the normal thick ones, the picoseconds short response time, and the MTE less than 70 meV, respectively. Given these properties, Ag F-P resonant ultra-thin GaAs NEA-PC represent a promising photocathode to provide the high-brightness short-pulse electron beams and high-sensitive fast-response detectors for the electron accelerator and photodetection applications, respectively.

Diluted Ternary Heterojunctions to Suppress Charge Recombination for Organic Solar Cells with 21% Efficiency.

As an exitonic photovoltaic device, organic solar cells (OSCs) consist of electron donating and accepting components in their photoactive layer, in which the molecular interactions between donor and acceptor can significantly affect the nanoscale morphology as well as the photovoltaic performance of OSCs. In this work, by diluting electron donor with electron acceptor having opposite electrostatic potentials to promote the structural order via strengthened intermolecular interactions, this study shows that polymeric diluent is more effective due to its long-ranged conjugated backbone compared with small molecular diluent. The ternary heterojunction made of C5-16:L8-BO binary acceptors diluted with D18 shows the strongest structural order, benefiting from the strong interactions between L8-BO and C5-16. The enhanced structural order within the photoactive layer prepared by layer-by-layer deposition of the diluted p-type and n-type heterojunctions contributes to enhanced light absorption, improved charge transport, and inhibited charge recombination. As the result, OSC based on D18 (PY-IT diluted)/L8-BO:C5-16 (D18 diluted) having donor and acceptor dual fibrils obtains an unprecedented power conversion efficiency of 21.0% (certified value of 20.25%), which is one of the highest certified PCE up to date.

Photocatalysis and adsorption coupling in S-scheme K and P doped g-C3N4/GO/MgFe2O4 photocatalyst for enhanced degradation of Congo red dye

Abstract Photocatalysis is an environmentally friendly approach for harnessing solar light to degrade pollutants. This study investigates the degradation of Congo red (COR) dye by a visible light-active photocatalyst, with a primary focus on the efficiency and reusability of the photocatalytic material. We synthesized phosphorus- and potassium-doped graphitic carbon nitride photocatalysts attached to graphene oxide and MgFe2O4 (KPCN/GO/MgFe2O4). Doping graphitic carbon nitride enhanced light absorption, while graphene oxide improved the adsorption properties. The addition of magnetic MgFe2O4 enhanced charge separation and reusability. The KPCN/GO/MgFe2O4 composite was analyzed using a range of techniques. The activity of the synthesized materials for Congo red (COR) dye degradation was analyzed under visible light. The photocatalytic activities of bare, binary, and ternary photocatalysts were compared, and KPCN/GO/MgFe2O4 exhibited the highest photoactivity among all. The KPCN/GO/MgFe2O4 photocatalyst (60 mg) showed a 76% removal efficiency for 5 x 10-6 M Congo red within 60 minutes, which was 2.5 times higher than that of pure graphitic carbon nitride. The •OH and •O2- were the major reactive species during COR photodegradation. The photocatalyst also displayed good reusability after five cycles, enhancing its overall effectiveness.

Study of Optical, Thermal, Electrical, and Impedance Properties of Li4Ti5O12-Based PEO/SA Biopolymer Blend Electrolytes for Lithium-Ion Batteries

Nanocomposites composed of polyethylene oxide (PEO) and sodium alginate (SA), containing varying contents of lithium titanium oxide nanoparticles (Li4Ti5O12NPs), were synthesized by solution casting technique. Li4Ti5O12 was incorporated into PEO/SA blend and is a valuable biopolymer for its biocompatibility, solubility and eco-friendliness. Structural analysis via X-ray diffraction spectroscopy revealed a decrease in the crystallinity of PEO/SA matrix with increasing nanoparticle content. Complementary Fourier transform infrared analysis verified the presence of strong molecular interactions between Li4Ti5O12 and the blend chains. Scanning electron microscopy verified a uniform dispersion of Li4Ti5O12 within PEO/SA blend, contributing to the improved properties of the electrolytes, while optical analysis showed a decrease in the bandgap energy, indicating enhanced light absorption and improved suitability for applications in nanodielectric devices. The thermal stability of PEO/SA/Li4Ti5O12 electrolyte samples was improved as shown by thermogravimetric analysis. Furthermore, a significant improvement in the ionic conductivity of the filled samples was observed, attributed to the reduced bulk resistance and improved charge transport pathways. Dielectric studies further showed improved dielectric permittivity and reduced dielectric losses for filled samples, enhancing the material’s charge storage capability. These findings highlight the potential of PEO/SA/Li4Ti5O12 biopolymer electrolytes for advanced applications in nanodielectric devices and lithium-ions batteries.

One‐step Synthesis of Phosphorus‐doped g‐C3N5 for the Photocatalytic Degradation of Tetracycline Hydrochloride

AbstractIn this study, phosphorus‐doped g‐C3N5 photocatalyst was synthesized by the thermal polycondensation method using 1‐Hydroxyethylidene‐1,1‐diphosphonic acid (HEDP) as the phosphorus source. The photoelectrochemical and photocatalytic performance of the catalyst were investigated through the characterization and analysis of its morphology, structure and photoelectric performance, as well as the discussion of the photocatalytic degradation mechanism. The results show that compared with undoped g‐C3N5, phosphorus doping can significantly enhance the specific surface area of g‐C3N5, reduce its band gap width, and expand its visible light absorption range. It can be substantiated that the phosphorus‐doped g‐C3N5 exhibits enhanced photocurrent response characteristics and a superior photocatalytic degradation efficiency. The degradation of tetracycline hydrochloride (TC‐HCl) was observed to occur rapidly and completely within 60 min under visible light irradiation. This considerable enhancement can be attributed primarily to the substitution of phosphorus into carbon sites through the formation of P‐N/P = N bonds with four coordination, which introduces additional P 2p levels within the band gap as a donor state, thereby facilitating enhanced light absorption and reducing charge separation. DFT calculations were conducted to analyze the electronic properties of P‐doped g‐C3N5 and to ascertain the mechanism by which P doping enhances the photocatalytic activity of g‐C3N5.

Improved absorption of phosphates through interface junctions and photothermal–energy–storage capability of Ca(OH)2–[Co3O4–Co3(PO4)2]

Improved absorption of phosphates through interface junctions and photothermal–energy–storage capability of Ca(OH)2–[Co3O4–Co3(PO4)2]

Effective killing of multidrug resistant bacteria by Bi2MoO6 nanospheres rich in oxygen vacancy under visible light

Effective killing of multidrug resistant bacteria by Bi2MoO6 nanospheres rich in oxygen vacancy under visible light

Air plasma sprayed multi-material composite coatings for enhanced light absorption and thermal emission

Air plasma sprayed multi-material composite coatings for enhanced light absorption and thermal emission

(ZnO)12 Cluster Decorated 2D Porous CN Materials as Efficient Solar Cells.

Developing high-performance solar cells is a practical way to improve clean energy conversion efficiency. However, the performance of solar cells faces challenges such as fast carrier combination, poor stability, and limited solar light harvesting. Herein, we propose a strategy by decorating periodic holes in two-dimensional (2D) porous carbon-nitrogen (CN) materials with a zero-dimensional (0D) semiconducting (ZnO)12 cluster. The effects of different CN substrates on the photogenerated carrier dynamics and solar cell performance are revealed by first-principles calculations combined with time-dependent ab initio nonadiabatic molecular dynamic (NAMD) simulations. With high structural stabilities, proper energy gaps of 1.81-3.23 eV, and positions, (ZnO)12/CN heterostructures possess enhanced light absorption in the visible region, excellent separation of photogenerated electron-hole pairs with carrier relaxation times of 140-773 ns for electrons and 82-128 ns for holes, and large short-circuit current densities of 15-34 mA cm-1. The study unveils the fundamental principles for optimizing the solar cell efficiency of metal oxide cluster decorated CN materials in energy conversion.