Internal Light Research Articles

A Flexible Antibacterial Gel Electrochemiluminescence Device for Monitoring and Therapy of Chronic Diabetic Wounds

ABSTRACTThe rapid development of internal light‐driven photodynamic therapy stems from its capability to eliminate bulky physical light sources, addressing the medical requirements for comfort and portability in long‐term diabetic wound management. To overcome limitations such as tissue penetration depth and controllability of internal light sources, this study introduces an antibacterial gel electrochemiluminescence device for the treatment of diabetic wounds and the monitoring of wound bacteria. We deploy a large‐area luminescent device combining flexible screen‐printed electrodes and a dual‐network hydrogel, in which photodynamic therapy is driven by Ru@COFs' nanoconfinement‐enhanced near‐infrared electrochemiluminescence to achieve a deeper and safer antibacterial effect. The custom‐sized screen‐printed electrodes inherit the inborn electrochemical sensing function and enable intimate contact between reactive oxygen species and the wound. The device avoids physical light sources and provides a new paradigm for developing miniaturized integrated diagnostic and therapeutic wearable devices.

Effect of pressure, temperature, and particle size on cold sintered ZnO for transparent thick films on polymer substrates

AbstractThe role of pressure, temperature, and particle size on cold sintering of ZnO has been investigated with a view to developing transparent thick films for device applications. Coarse ZnO (∼90–250 nm, cZnO) particles exhibited equiaxed grain growth under all conditions eventually achieving grain sizes of ∼ 0.5–1.0 µm at 300°C/375 MPa. In contrast, nano‐ZnO (40–80 nm, nZnO), exhibited grain growth along the c‐axis with a broader grain size distribution (0.5–4 µm) at higher temperatures and pressure (300°C/375 MPa) than cZnO. The broader grain size distribution is attributed to greater dissolution for nZnO compared with cZnO coupled with redistribution of Zn acetate/acetic acid into pores. ZnO continues to dissolve and reprecipitate within the pores throughout the densification process resulting in localized, larger grain sizes. In plane grain growth normal to the pressing direction was observed at and near the sample surface particularly in nZnO, which is attributed to constrained‐sintering. Some abnormal grain growth (10–20 µm) was also sporadically observed near or at the surface of nZnO (300°C/375 MPa) due to greater rates of reprecipitation as the transient solvent volatilizes adjacent to the die wall/plunger. Tape casting was used to fabricate single and multiple layers (≈30 µm) of ZnO on Kapton® to demonstrate the potential for device fabrication. Transparency was achieved by choosing cold sintering conditions (200°C/250 MPa) for nZnO that gave ∼95% relative density while restricting a majority of grain growth to <200 nm so that internal light scattering from grain boundaries was avoided.

Synergistic effect of graphdiyne (C2H2n-2) based hollow spherical Cu2O/GDY and NiS dual cocatalysts boosting photocatalytic hydrogen evolution

The control of carrier separation morphology and efficiency is a key strategy for preparing high-performance photocatalysts. In this study, Cu2O/graphdiyne was introduced into NiS in the form of hollow nanospheres, creating a novel composite material. This method improved upon the traditional graphdiyne fabrication processes that typically use copper foil. Through the hollow spherical structure, both internal and external surface light scattering and reflection were significantly enhanced, indirectly enhancing the light absorption rate of the photocatalyst and photocatalytic activity. Ultraviolet-visible spectroscopy and photoelectrochemical results showed that using NiS as the external cocatalyst and Cu2O as the internal cocatalyst are the driving factors for the hydrogen evolution reaction, with a synergistic effect that accelerated the reaction. Such synergistic catalytic effects are rare in traditional photocatalytic systems, indicating their potential application value in enhancing catalytic efficiency. The overall performance was more than 22 times that of Cu2O/graphdiyne alone and more than 2.6 times that of NiS. Additionally, the electronic band structures and reaction mechanisms can be elucidated through Density Functional Theory (DFT) calculations, Ultraviolet Photoelectron Spectroscopy (UPS) and UV-Vis spectroscopy. These findings not only offer practical guidance but also underscore the significance of precisely manipulating the components of composite catalysts to optimize performance.

Enhanced forward emission by backside mirror design in micron-sized LEDs.

Tiny InGaN micro-LEDs (μ-LEDs) play a pivotal role in emerging display technologies, particularly augmented reality (AR) applications. Achieving both high internal quantum efficiency (IQE) and efficient light extraction efficiency (LEE) is essential. While wet chemical etching can recover the IQE after dry etching, it alters the pixel shape, impacting optical properties and reducing the LEE. In this study, we overcome this issue by fabricating 1 μm thin-film-based μ-LED emitter arrays with a metallic backside mirror deposited on a patterned dielectric material around the μ-LED mesa. This concave mirror can be straightforwardly integrated into a thin-film LED process chain, and it redirects photons within the μ-LED structure, enhancing the LEE in the forward direction. Electro-optical measurements show a 2.1-fold improvement in light output within the ±15∘ emission cone compared to μ-LEDs with vertical sidewalls. These findings hold significant implications for μ-LED projection displays, where maximizing the overall efficiency and directionality is critical.

Glare Reduction of the Artificial Lighting System Using the Digital Software Solution

Artificial lighting systems are an integral part of production halls. These systems are typically used to supplement daylight, although in some cases they are the sole source of lighting in the workplace. Every artificial lighting system is accompanied by an unfavourable phenomenon: glare. This phenomenon is one of the main factors affecting the quantitative parameters of internal lighting systems. Glare needs to be reduced in each production area to ensure visual well-being, which is linked to the visual performance of employees and consequently affects the efficiency and productivity of production. Obtaining information about glare in a real system is a difficult and lengthy process. However, digital software tools can be used in a simulated environment to predict and reduce glare. This article addresses the issue of reducing glare in artificial lighting systems using a digital software solution. The introduction discusses the theoretical aspects of glare caused by artificial lighting systems. This is followed by a practical example using the simulation method with the Dialux Evo tool to reduce glare in the workplace. The conclusion of the article provides an analysis of the results achieved and offers recommendations for practical implementation.

Highly efficient and sustainable photocatalytic Fenton reactions utilizing catalyst-embedded inverse-opal structured membranes

The inverse opal (IO) structure, known for its photonic crystal properties and uniform pores, promotes multiple internal light scatterings and reflections. This leads to a decrease in photon group velocity, generating a slow photon effect. When integrated with photocatalysts, this effect enhances light absorption by extending photon interaction with the catalyst, thereby significantly enhancing the efficacy of IO structures in photocatalytic applications. However, the integration of inorganic photocatalysts into IO structures presents challenges, such as mechanical brittleness and a tendency to form powders. To overcome these obstacles, we have engineered IO-structured polymeric membranes coated with graphitic carbon nitride tailored for photocatalytic Fenton reactions. These membranes, which encapsulate photocatalysts within the polymeric porous IO framework, facilitate the straightforward reaction and separation of catalysts from byproducts. They demonstrated superior photocatalytic performance, as evidenced by Rhodamine B degradation (∼7.1 %) and benzene hydroxylation (∼7.3 %). Extensive durability (>30 days) and recyclability tests (>5 times) confirmed their robustness, establishing their utility for various organic conversion reactions. By combining the advantages of the IO structure with tailored photocatalytic properties, these membranes offer promising potential for sustainable and efficient water treatment and the production of fine chemicals in industrial settings.

Amphiphilic Cationic Carbon Dots for Efficient Delivery of Light-Dependent Herbicide.

The inefficient delivery of herbicides causes unpleasant side effects on the ecological environment. Protoporphyrinogen oxidase (PPO)-inhibiting herbicides rely on the presence of external light to exert the activities and thus their performance in the field is extremely susceptible to the light environment. Here, taking acifluorfen (ACI) as a model PPO-inhibiting herbicide to enhance efficacy by boosting the utilization rate of sunlight, amphiphilic cationic CDs (CPC-CDs) from cetylpyridinium chloride (CPC) as a precursor, is first prepared as a supplementary light source generator, and subsequently co-assembled with ACI through non-covalent bond interactions to obtain the stable fluorescent nanoparticles (ACI@CPC-CDs). ACI@CPC-CDs with fascinating physicochemical properties can penetrate the leaves of weeds through the stomata and undergo a long-distance transport in the cell intervals. Under low light intensity, CPC-CDs can be applied as the internal light source to promote the formation of more singlet oxygen to damage the leaf cell membrane, consequently improving the herbicidal activity of ACI. Moreover, the safety evaluation of ACI@CPC-CDs demonstrates no risk to non-target organisms and the environment. Therefore, this work offers a promising strategy for the efficient delivery of light-dependent PPO-inhibiting herbicides and opens new insights into the application of CDs in the development of sustainable agriculture.

Development of a Self-Luminescent Living Bioreactor for Enhancing Photodynamic Therapy in Breast Cancer.

The penetration ability of visible light (<2 mm) and near-infrared (NIR) light (∼1 cm) remarkably impairs the therapeutic efficacy and clinical applications of photodynamic therapy (PDT). To address the limitation of light penetration depth, a novel self-luminescent bacterium, teLuc.FP-EcN, has been engineered through transfection of a fusion expression plasmid containing the luciferase gene teLuc and bright red fluorescent protein mScarlet-I into Escherichia coli Nissle 1917 (EcN). The engineered teLuc.FP-EcN can specifically target and colonize tumors without significant toxicity to the host. Acting as a continuous internal light source, teLuc.FP-EcN can activate the photosensitizer chlorin e6 (Ce6) to generate reactive oxygen species (ROS) and then effectively destroy tumor tissue from the inside. As a result, a significant reduction in tumor proliferation and extension of the overall survival in mouse tumor models has been observed. Furthermore, teLuc.FP-EcN-boosted PDT amplified its therapeutic effect by activating antitumor immune response, including the conversion of M2 macrophages into pro-inflammatory M1 macrophages, as well as an increase in the proportion of CD3+ T cells and a decrease in T-cell exhaustion. In conclusion, teLuc.FP-EcN can be used as an implantable light source for tumor phototherapy, which simultaneously possesses ROS generation and immune regulation.

Tumor microenvironment-modulated nanoparticles with cascade energy transfer as internal light sources for photodynamic therapy of deep-seated tumors

Photodynamic therapy (PDT) is an appealing modality for cancer treatments. However, the limited tissue penetration depth of external-excitation light makes PDT impossible in treating deep-seated tumors. Meanwhile, tumor hypoxia and intracellular reductive microenvironment restrain the generation of reactive oxygen species (ROS). To overcome these limitations, a tumor-targeted self-illuminating supramolecular nanoparticle T-NPCe6-L-N is proposed by integrating photosensitizer Ce6 with luminol and nitric oxide (NO) for chemiluminescence resonance energy transfer (CRET)-activated PDT. The high H2O2 level in tumor can trigger chemiluminescence of luminol to realize CRET-activated PDT without exposure of external light. Meanwhile, the released NO significantly relieves tumor hypoxia via vascular normalization and reduces intracellular reductive GSH level, further enhancing ROS abundance. Importantly, due to the different ROS levels between cancer cells and normal cells, T-NPCe6-L-N can selectively trigger PDT in cancer cells while sparing normal cells, which ensured low side effect. The combination of CRET-based photosensitizer-activation and tumor microenvironment modulation overcomes the innate challenges of conventional PDT, demonstrating efficient inhibition of orthotopic and metastatic tumors on mice. It also provoked potent immunogenic cell death to ensure long-term suppression effects. The proof-of-concept research proved as a new strategy to solve the dilemma of PDT in treatment of deep-seated tumors.

Internal light-driven efficient chemiluminescence of graphitic carbon nitride quantum dots for improved carboxin sensing

Developing a new chemiluminescence (CL) sensor platform to achieve the identification of pollutants in the water environment is a significant and currently hot topic for researchers. Building on the effective development of a CL internal light source, this paper designed a direct, simple, and rapid pesticide identification strategy. Specifically, graphite carbon nitride quantum dots (CNQDs) with excellent optical properties were synthesized using a solvent heat treatment strategy. Acting as an energy acceptor, CNQDs triggered CL emission in the presence of singlet oxygen (1O2). The newly developed CNQDs/1O2 CL sensor exhibited a specific response toward carboxin (CBX) with high sensitivity. Based on this discovery, we have developed a highly selective, ultra-sensitive, and fast CL sensing platform for detecting CBX in water environments. Through numerous experiments, we attributed the CL emission of the CNQDs/1O2 system to the specific chemiluminescent resonance energy transfer (CRET) process between CNQDs and 1O2. Interestingly, the CL light of the CNQDs/1O2 system could serve as an internal light source to excite CBX generating a large amount of 1O2 through photosensitization, which was crucial for further enhancing the CL efficiency of the CNQDs/1O2/CBX system and also enabled the CL sensing of CBX. This study is the first to successfully identify CBX in water using CL sensors, showcasing the potential of CL internal light sources in regulating CL efficiency and offering new perspectives on detecting pollutants in complex environments.

Photovoltaic enhancement in OSCs based on PM6:Y7 when doping the active layer with Ag2S nanoparticles

Herein, silver sulfide (Ag2S) nanoparticles (NPs) with an average size of 31 nm ± 4 nm were synthesized using a simple, economic, and eco-friendly method assisted by ultrasonic bathing; the reaction was carried out in a non-polluting aqueous medium. These Ag2S NPs were suspended in ethanol and used to dope the active layer of Organic Solar Cells (OSCs) based on PM6 (donor) and Y7 (acceptor) by adding 2 v/v % of a suspension to the PM6:Y7 solution in chlorobenzene (CB). The entire fabrication process and testing was carried out under normal atmospheric conditions. Field's metal (FM) was used as the top electrode of the OSCs, which is a eutectic alloy of bismuth, indium, and tin (Bi 32.5 %, In 51 %, and Sn 16.5 %) with a melting point above 62 °C deposited by free evaporation techniques. The average Power Conversion Efficiency (PCE) for the reference and doped OSCs were 9.19 % (9.43 % the best) and 10.31 % (10.77 % the best), respectively; representing an increase of more than 14 % in the PCE value when Ag2S NPs are added to the active layer. It can be attributed to different optical phenomena, among which could be the enhance in the internal light reflection processes (scattering) and the Local Surface Plasmon Resonance (LSPR) effect.

Structure design for light‐extraction enhancement of UVC‐LED

AbstractUVC‐LEDs have drawn attention recently because of their benefits to sterilization, decontamination, etc. Since the internal quantum efficiency and light extraction efficiency (LEE) of UVC‐LEDs are low, their external quantum efficiency remains unsatisfied. To enhance the LEE, this study proposes an integration design with the features of substrate‐thickness optimization, substrate shaping, diffuse‐reflective coating, an index‐matching layer, and taper‐base optimization. In addition to optical modeling via ray tracing, thermal modeling is conducted to evaluate both the optical and thermal performances of each feature. The simulation results show that, by means of the combination of these features, the LEE of the chip can be raised from 18.5% to more than 40%, and the average temperature of the device can be lowered by 2.2°C via the design of the diffuse‐reflective coating.

Bioluminescent Systems for Theranostic Applications.

Bioluminescence, the light produced by biochemical reactions involving luciferases in living organisms, has been extensively investigated for various applications. It has attracted particular interest as an internal light source for theranostic applications due to its safe and efficient characteristics that overcome the limited penetration of conventional external light sources. Recent advancements in protein engineering technologies and protein delivery platforms have expanded the application of bioluminescence to a wide range of theranostic areas, including bioimaging, biosensing, photodynamic therapy, and optogenetics. This comprehensive review presents the fundamental concepts of bioluminescence and explores its recent applications across diverse fields. Moreover, it discusses future research directions based on the current status of bioluminescent systems for further expansion of their potential.

Internal and external spectral light conversion amplifying growth/bio-products formation of Dunaliella salina

Internal and external spectral light conversion amplifying growth/bio-products formation of Dunaliella salina

Wireless Powered Microwave-Light Conversion Platform with Dual-Stimulus Nanoresponder Coating for Deep-Seated Photodynamic Therapy.

Traditional external field-assisted therapies, e.g., microwave (MW) therapy and phototherapy, cannot effectively and minimally damage eliminate deep-seated infection, owing to the poor penetrability of light and low reactive oxygen species (ROS) stimulation capability of MW. Herein, an implantable and wireless-powered therapeutic platform (CNT-FeTHQ-TS), in which external MW can be converted into internal light via MW wireless-powered light-emitting chips, is designed to eradicate deep-seated tissue infections by MW-induced deep-seated photodynamic therapy. In application, CNT-FeTHQ-TS is implanted at internal lesions, and the chip emits light under external MW irradiation. Subsequently, CNT-FeTHQ coating in the platform can respond to both MW and light simultaneously to generate ROS and MW-hyperthermia for rapid and precise sterilization at focus. Importantly, MW also improves the photodynamic performance of CNT-FeTHQ by introducing vacancies in FeTHQ to facilitate the photoexcitation process and changing the spin state of electrons to inhibit the complexation of photogenerated electron-hole pairs, which were confirmed by simulation calculations and in situ MW-irradiated photoluminescence experiments. In vivo, CNT-FeTHQ-TS can effectively cure mice with Staphylococcus aureus infection in dorsal subcutaneous tissue. This work overcomes the key clinical limitations of safe energy transmission and conversion for treating deep-seated infections.

Comparative Study on Temperature‐Dependent Internal Quantum Efficiency and Light–Extraction Efficiency in III‐Nitride–, III‐Phosphide–, and III‐Arsenide–based Light‐Emitting Diodes

This study attempts to understand and elucidate the factors limiting/determining the external quantum efficiency (EQE) of light‐emitting diodes (LEDs) depending on material systems, i.e., III‐arsenide (GaAs), III‐phosphide (AlGaInP), and III‐nitride (GaInN), via the temperature measurements (30–500 K). The behaviors of EQEs are investigated carefully in terms of the thermal droop and efficiency droop, revealing that the thermal droop in the AlGaInP and GaAs LEDs, while the efficiency droop in the GaInN LEDs, is a critical factor limiting the EQE. To deepen the insight, the EQE is separated into internal quantum efficiency (IQE) and light‐extraction efficiency (LEE). Further, the IQE is separated into radiative efficiency (RE) and injection efficiency (IE). The analysis shows that the LEE plays a significant role in the thermal droop for the AlGaInP and GaAs LEDs. Meanwhile, the IE and RE play a significant role in the EQE reduction of the blue and red LEDs at high temperatures and high current injection.

Solvent-Reconstructed Interface That Enhances Light Out-Coupling in Quasi-Two-Dimensional Perovskite Light-Emitting Diodes.

Light management is critical to maximizing the external quantum efficiency of perovskite light-emitting diodes (PeLEDs), but strategies for enhancing light out-coupling are typically complex and expensive. Here, using a facile solvent treatment strategy, we create a layer of lithium fluoride (LiF) nanoislands that serve as a template to reconstruct the light-extracting interfaces for PeLEDs. The nanoisland interface rearranges the near-field light distribution in order to maximize the efficiency of internal light extraction. With the proper adjustment of the nanoisland size and distribution, we have achieved an optimal balance between charge injection and light out-coupling, resulting in bright, pure-red quasi-two-dimensional PeLEDs with a 21.8% peak external quantum efficiency.

Measurement of light absorption by chromophoric dissolved organic matter using a type-II liquid capillary waveguide: assessment of an achievable accuracy

Light absorption by chromophoric dissolved organic matter (CDOM) in the ocean is often measured using liquid waveguide capillary cells coupled to spectral array detectors. This type of optical setup is affected by several sources of uncertainties related to the waveguide and the detector. Uncertainties from the waveguide arise from errors in the effective path length and the effects of water salinity, while errors related to the detector are due to the non-linearity in the response, internal stray light, and wavelength accuracy. Here, uncertainties in the measurements of the spectral absorption coefficient of CDOM due to the optical setup itself were investigated in detail. The related systematic errors were very often significant (2–15%) and larger than expected from simple measurement uncertainty (±1%). However, they can be corrected by characterizing the detector’s response for non-linearity and stray light, regularly performing calibrations for the detector’s wavelength response, and routinely measuring the waveguide’s effective path length. Including such corrections and timely calibrations reduces the uncertainties related to the spectrophotometric measurements to about ±2%. Uncertainties related to the necessary handling of samples are not included here.

Transparent Nanofibrous Membranes with Optimized Optical Channel Structure for Window Screens

AbstractNanofibrous membranes, characterized by their flexibility, high porosity, and tunable structure, are emerging as a promising contender for advanced transparent materials with sufficient breathability and pliability. However, the considerable surface light reflection and internal light scattering of nanofibrous membranes pose a challenging task in achieving transparency. In this study, transparent nanofibrous membranes are fabricated by constructing a topological structure with optimized optical transmission channels, which provide the minimum equivalent thickness to minimize light loss in nanofibrous membranes. The resultant fabricated membrane exhibits a high light transmittance of up to 81%, along with a sufficient porosity of 84% and flexibility. Additionally, the membrane demonstrated effective PM0.3–10 removal efficiency (&gt;91%), low air pressure drops (&lt;110 Pa), high air permeability (≈104 mm s−1), and good waterproof performance. Therefore, the prepared transparent nanofibrous membrane may serve as a transparent air filtration window screen to enhance indoor comfort for people.

Research on optical simulation of dim target based on passive detection link analysis

In order to meet the ground calibration requirements of optical detection equipment to identify optical characteristics of dim targets, an optical simulation method of dim targets based on passive detection link analysis and bidirectional scattering distribution function model is proposed. The off-axis collimation system for long focal length, the simulated energy transmission model of dim targets and the simplified model of bidirectional scattering distribution function are established. An internal stray light suppression baffle was designed to effectively suppress secondary scattering, and an optical simulation system for dim targets was built. The experimental results show that the system can simulate +7 Mv∼+20 Mv, and the simulation accuracy is better than 0.07 Mv. At the same time, the detection ability of the camera is tested by using the +15 Mv point simulated by the system. The signal-to-noise of the star point target reaches 6.7, which meets the requirements of detection rate and false alarm rate, and realizes the ground test of the camera's detection ability of the dim target.