Search Results (612)

Photobiomodulation (PBM) harnesses near-infrared (NIR) light to stimulate cellular processes, offering non-invasive treatment options for a range of conditions, including chronic wounds, inflammation, and neurological disorders. NIR light-emitting diodes (LEDs) are emerging as safer and more scalable alternatives to conventional lasers, but optimizing their performance for clinical use remains a challenge. This perspective explores the latest advances in NIR-emitting materials, spanning Group III–V, IV, and II–VI semiconductors, organic small molecules, polymers, and perovskites, with an emphasis on their applicability to PBM. Particular attention is given to the promise of perovskite LEDs, including lead-free and lanthanide-doped variants, for delivering narrowband, tunable NIR emission. Furthermore, we examine photonic and plasmonic engineering strategies that enhance light extraction, spectral precision, and device efficiency. By integrating advances in materials science and nanophotonics, it is increasingly feasible to develop flexible, biocompatible, and high-performance NIR LEDs tailored for next-generation therapeutic applications. Full article

Organic light-emitting diodes (OLEDs) have emerged as a critical battleground in display technology due to their self-emissive and foldable properties. However, the adoption of polyimide (PI) as a flexible substrate material introduces technical challenges, particularly image sticking. This study proposes an interfacial polarization mechanism to explain this phenomenon, confirmed through dielectric and ferroelectric spectroscopy. The results show that introducing an amorphous silicon (α-Si) interlayer significantly improves interface compatibility, increasing the polarization response frequency from 74 Hz to 116 Hz and reducing residual polarization strength from 2.81 nC/cm² to 1.00 nC/cm². Practical tests on OLED devices demonstrate that the optimized structure (PI/α-Si/SiO₂) lowers the image sticking score from 3.46 to 1.67, validating the proposed mechanism. This research provides both theoretical insights and practical solutions for mitigating image sticking in flexible OLED displays. Full article

Advances in OLED display technology have increased the demand for high-performance luminescent materials, yet efficient red emitters with narrow emission spectra remain rare. Here, two new polycyclic compounds (O-QA and S-QA) are designed by incorporating oxygen/sulfur into a carbonyl/nitrogen skeleton. Photophysical and theoretical studies reveal their hybridized local and charge-transfer state characteristics. In toluene, O-QA and S-QA show photoluminescence peaks at 586/579 nm with narrow emission spectra, while doped films exhibit strong red emissions peaking at 598/600 nm with high PL quantum yields of 67%/60%. The OLEDs using these emitters achieve red electroluminescence (EL) peaks at 598/602 nm, and attain maximum external quantum efficiencies of 7.36%/14.54%. This work may provide guidance for the development of narrow-spectrum red emitters based on carbonyl/nitrogen frameworks. Full article

The dimensional accuracy of the intaglio surface of complete dentures fabricated using liquid crystal display (LCD) three-dimensional (3D) printing might be influenced by the build angle and post-processing storage conditions. This study evaluated the effect of build angle and natural light exposure duration on the intaglio surface trueness of maxillary complete denture bases. Standardized denture base designs (2 mm uniform thickness) were fabricated using an LCD 3D printer (Lilivis Print; Huvitz, Seoul, Republic of Korea) at build angles of 0°, 45°, and 90° (n = 7 per group). All specimens were printed using the same photopolymer resin (Tera Harz Denture; Graphy, Seoul, Republic of Korea) and identical printing parameters, followed by ultrasonic cleaning and ultraviolet post-curing. Specimens were stored under controlled light-emitting diode lighting and exposed to natural light (400–800 lux) for 0, 14, or 30 days. The intaglio surfaces were scanned and superimposed on the original design data, following the International Organization for Standardization 12836. Quantitative assessment included root mean square deviation, mean deviation, and tolerance percentage. Statistical analyses were performed using one-way analysis of variance and paired t-tests (α = 0.05). Build angle and light exposure duration significantly affected surface trueness (p < 0.05). The 90° build angle group exhibited the highest accuracy and dimensional stability, while the 0° group showed the greatest deviations (p < 0.05). These findings underscore the importance of optimizing build orientation and storage conditions in denture 3D printing. Full article

Irradiation with ultraviolet light-emitting diodes (UV-LEDs) represents a promising method for viral inactivation, but a detailed understanding of the wavelength-dependent action spectra remains limited, particularly across different viral components. In this study, we established standardized UV action spectra for infectivity reduction in pathogenic viruses using a system equipped with interchangeable LEDs at 13 different peak wavelengths (250–365 nm). The reduction in viral infectivity induced by UV-LED exposure was strongly related to viral genome damage, whereas no significant degradation of viral structural proteins was detected. Peak virucidal efficiency was observed at 267–270 nm across all tested viruses, representing a slight shift from the traditionally expected 260 nm nucleic acid absorption peak. Enveloped RNA viruses, including influenza A virus, respiratory syncytial virus, and coronavirus, exhibited greater UV sensitivity than nonenveloped viruses such as feline calicivirus and adenovirus. These observations indicate that structural characteristics, such as the presence of an envelope and genome organization, influence UV susceptibility. The wavelength-specific action spectra established in this study provide critical data for optimizing UV-LED disinfection systems to achieve efficient viral inactivation while minimizing energy consumption in healthcare, food safety, and environmental sanitation. Full article

Tunnel construction poses significant safety challenges due to confined spaces, limited visibility, and the dynamic movement of labourers and machinery. This study addresses a critical gap in real-time, bidirectional proximity monitoring by developing and validating a prototype early-warning system that integrates real-time location systems (RTLS) with long-range (LoRa) wireless communication and ultra-wideband (UWB) positioning. The system comprises Arduino nano microcontrollers, organic light-emitting diode (OLED) displays, and piezo buzzers to detect and signal proximity breaches between workers and equipment. Using an action research approach, three pilot case studies were conducted in a simulated tunnel environment to test the system’s effectiveness in both static and dynamic risk scenarios. The results showed that the system accurately tracked proximity and generated timely alerts when safety thresholds were crossed, although minor delays of 5–8 s and slight positional inaccuracies were noted. These findings confirm the system’s capacity to enhance situational awareness and reduce reliance on manual safety protocols. The study contributes to the tunnel safety literature by demonstrating the feasibility of low-cost, real-time monitoring solutions that simultaneously track labour and machinery. The proposed RTLS framework offers practical value for safety managers and informs future research into automated safety systems in complex construction environments. Full article

The fabrication of high-performance organic optoelectronic devices using solution-based techniques, in particular inkjet printing, is both a desirable and challenging goal. Organic light-emitting diodes (OLEDs) are multilayer devices that have demonstrated great potential in display applications, with ongoing efforts aimed at extending their use to the lighting sector. A key objective in this context is the reduction in production costs, for which printing techniques offer a promising pathway. The main obstacle to fully printed OLEDs lies in the difficulty of depositing new layers onto pre-existing ones while maintaining high film quality and avoiding damage to the underlying layers. In a bottom-emitting OLED, the electron transport layer (ETL) is the final organic layer to be deposited, making its printing particularly challenging, a process for which only a few successful examples have been reported. In this work, we report on the optimization of a 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)-based ink formulation for ETL printing on an emitting layer composed of 5,10-Bis(4-(3,6-di-tert-butyl-9H-carbazol-9-yl)-2,6-dimethylphenyl)-5,10-dihydroboranthrene (tBuCzDBA). A specific ratio of methanol to diethyl ether was identified as the most suitable for printing the ETL without compromising the integrity of the underlying layer. The printed ETL was successfully integrated into an OLED device, which exhibited a maximum current efficiency of 6.8 cd/A and a peak luminance of about 8700 cd/m². These results represent a significant step toward the development of a fully printed OLED architecture. Full article

The application of organic light-emitting diodes (OLEDs) has become widespread, with polarizers commonly employed to mitigate the influence of external light sources on OLED displays. However, when the light signal generated by the OLED emissive layer passes through the polarizer, approximately 50% of the light energy is inevitably lost. Circularly polarized luminescent (CPL) molecules, capable of emitting specific left- or right-handed circularly polarized light, theoretically enable 100% light energy utilization in corresponding OLED devices (CP-OLEDs). With this breakthrough, CPL mechanisms exhibit significant potential for applications in data storage, bioimaging, and 3D displays. In this review, we focus on molecules constructed via a chiral perturbation strategy, analyzing their CPL generation mechanisms and molecular engineering principles. The relationship between these molecular structures and OLED performance is systematically analyzed and summarized. Finally, we critically address current challenges in developing both CPL active materials and devices based on the chiral perturbation strategies, while providing perspectives on future developments and potential challenges in this field. Full article

Transparent conductive electrodes (TCEs) are essential components in modern optoelectronic devices, including organic light-emitting diodes and solar cells, sensors, and flexible displays. Indium tin oxide has been the dominant material for TCEs due to its high transparency and conductivity. However, its brittleness, high cost, and increasingly limited availability pose significant challenges for electronics. Crack-template (CT)-assisted fabrication has emerged as a promising technique to develop metal mesh-based TCEs with superior mechanical flexibility, high conductivity, and excellent optical transmittance. This technique leverages the spontaneous formation of random and continuous microcrack networks in sacrificial templates, followed by metal deposition (e.g., Cu, Ag, Al, etc.), to produce highly conductive, scalable, and low-cost electrodes. Various crack formation strategies, including controlled drying of polymer suspensions, mechanical strain engineering, and thermal processing, have been explored to tailor electrode properties. Recent studies have demonstrated that crack-templated TCEs can achieve transmittance values exceeding 85% and sheet resistances below 10 Ω/sq, with mesh line widths as low as ~40 nm. Moreover, these electrodes exhibit enhanced stretchability and robustness under mechanical deformation, outperforming ITO in bend and fatigue tests. This review aims to explore recent advancements in CT engineering, highlighting key fabrication methods, performance metrics across different metals and substrates, and presenting examples of its applications in optoelectronic devices. Additionally, it will examine current challenges and future prospects for the widespread adoption of this emerging technology. Full article

Titanium dioxide (TiO₂) is a wide-bandgap semiconductor material with broad application potential, known for its excellent photocatalytic performance, high chemical stability, low cost, and non-toxicity. These properties make it highly attractive for applications in photovoltaic energy, environmental remediation, and optoelectronic devices. For instance, TiO₂ is widely used as a photocatalyst for hydrogen production via water splitting and for degrading organic pollutants, thanks to its efficient photo-generated electron–hole separation. Additionally, TiO₂ exhibits remarkable performance in dye-sensitized solar cells and photodetectors, providing critical support for advancements in green energy and photoelectric conversion technologies. Boron-doped diamond (BDD) is renowned for its exceptional electrical conductivity, high hardness, wide electrochemical window, and outstanding chemical inertness. These unique characteristics enable its extensive use in fields such as electrochemical analysis, electrocatalysis, sensors, and biomedicine. For example, BDD electrodes exhibit high sensitivity and stability in detecting trace chemicals and pollutants, while also demonstrating excellent performance in electrocatalytic water splitting and industrial wastewater treatment. Its chemical stability and biocompatibility make it an ideal material for biosensors and implantable devices. Research indicates that the combination of TiO₂ nanostructures and BDD into heterostructures can exhibit unexpected optical and electrical performance and transport behavior, opening up new possibilities for photoluminescence and rectifier diode devices. However, applications based on this heterostructure still face challenges, particularly in terms of photodetector, photoelectric emitter, optical modulator, and optical fiber devices under high-temperature conditions. This article explores the potential and prospects of their combined heterostructures in the field of optoelectronic devices such as photodetector, light emitting diode (LED), memory, field effect transistor (FET) and sensing. TiO₂/BDD heterojunction can enhance photoresponsivity and extend the spectral detection range which enables stability in high-temperature and harsh environments due to BDD’s thermal conductivity. This article proposes future research directions and prospects to facilitate the development of TiO₂ nanostructured materials and BDD-based heterostructures, providing a foundation for enhancing photoresponsivity and extending the spectral detection range enables stability in high-temperature and high-frequency optoelectronic devices field. Further research and exploration of optoelectronic devices based on TiO₂-BDD heterostructures hold significant importance, offering new breakthroughs and innovations for the future development of optoelectronic technology. Full article

A tetradentate Pt(II) complex with a 5/6/6 structural backbone, Pt(PhPiPy-O-PytmCz), was synthesized by incorporating two distinct cycloalkyl groups. These structural modifications significantly enhanced the photoluminescence quantum yield and effectively increased the distance between molecules, thereby mitigating undesirable intermolecular interactions and triplet-state quenching. This strategic molecular design resulted in an external quantum efficiency of 11.5% at a wavelength of 539 nm and significantly enhanced operational lifetimes in green phosphorescent organic light-emitting diodes (OLEDs). These findings are expected to inspire the development of new green luminescent materials and innovative strategies in OLED technology. Full article

Humans are continuously exposed to blue light from sunlight, computers, and smartphones. While blue light has been reported to affect living organisms, its role in fat synthesis and weight changes remains unclear. In this study, we investigated the effects of prolonged blue light exposure on weight changes in mice and the protective role of tranexamic acid (TA). Mice were exposed daily to blue light from a light-emitting diode for five months. Blue light exposure led to increased fat mass and body weight. The expression of the clock genes arnt-like 1 (Bmal1) and Clock was reduced in the brain and muscle of exposed mice. In addition, reduced Sirt1 and increased mammalian target of rapamycin complex 1 (mTORC1)/sterol regulatory element-binding protein 1 (SREBP1) were observed. The levels of liver X receptor a and liver kinase B1/5′AMP-activated protein kinase a1, both involved in SREBP1-mediated lipogenesis, were also elevated. TA treatment prevented the blue light-induced suppression of Bmal1/Clock and modulated the subsequent series of signal transduction. These findings suggest that prolonged blue light exposure suppresses the clock gene Bmal1/Clock, reduces Sirt1, and activates lipogenic pathways, contributing to weight gain. TA appears to regulate clock gene expression and mitigate blue light-induced weight gain. Full article

Recent advancements in thermally activated delayed fluorescence (TADF) materials and mechanochromic materials have significantly enhanced the efficiency and versatility of light-emitting electrochemical cells (LECs) and organic light-emitting diodes (OLEDs). TADF materials have enabled efficiency improvements, achieving an internal quantum efficiency (IQE) of nearly 100% by utilizing both singlet and triplet excitons. Meanwhile, mechanochromic materials exhibit reversible optical changes upon mechanical stimuli, making them promising for stress sensing, encryption, and flexible electronics. The synergistic integration of TADF and mechanochromic materials in OLEDs and LECs has led to enhanced efficiency, stability, and multifunctionality in next-generation lighting and display technologies. This narrative review explores recent breakthroughs in devices that incorporate both TADF and mechanochromic materials as emitters. Particular attention is given to the molecular design that enable both TADF and mechanochromic properties, as well as optimal device structures and performance parameters. Moreover, this review discusses the only LEC fabricated so far using a TADF-mechanochromic emitter, highlighting its performance and potential. Finally, the report concludes with an outlook on the future commercial applications of these materials, particularly in wearable electronics and smart display technologies. Full article

Printing techniques have been instrumental in developing flexible and stretchable electronics, including organic light-emitting diode displays, organic thin film transistor arrays, electronic skins, organic electrochemical transistors for biosensors and neuromorphic computing, as well as flexible solar cells with low-cost processes such as inkjet printing, ultrasonic nozzle, roll-to-roll coating. The rise of additive manufacturing provides even more opportunities to print electronics in automated and customizable ways. In this work, we will review the current technologies of printing electronics (including printed batteries, supercapacitors, fuel cells, and sensors), especially with 3D printing. In this age of ongoing AI revolution, the application of AI algorithms is discussed in terms of combining them with 3D printing and electronics printing for a future with automated optimization, sustainable design, and customizable and scalable manufacturing. Full article

Cellulose nanofibril (CNF) is a sort of novel nanomaterial directly extracted from plant resources, inheriting the advantages of cellulose as a cheap, green and renewable material for the development of new-generation eco-friendly electronics. In recent years, CNF-based triboelectric nanogenerator (TENG) has attracted increasing research interests, as the unique chemical, morphological, and electrical properties of CNF render the device with considerable flexibility, mechanical strength, and triboelectric output. In this study, we explore the use of isoreticular metal-organic frameworks (IRMOF) as functional filler to improve the performance of CNF based TENGs. Two types of IRMOFs that own the same network topology, namely IRMOF-1 and its aminated version IRMOF-3, are embedded with CNF to fabricated TENGs; their contribution to triboelectric output enhancement, including the roughness effect induced by large particles as well as the charge induction effect arisen from -NH₂ groups, are discussed. The performance-enhanced CNF-based TENG with 0.6 wt.% of IRMOF-3 is utilized to harvest mechanical energy from human activities and charge commercial capacitors, from which the electrical energy is sufficient to light up light-emitting diodes (LEDs) and drive low-power electronic devices. In addition, a locomotor analysis system is established by assembling the above TENGs and capacitors into a 3 × 3 sensing array, which allowed signal extraction from each sensing unit to display a motion distribution map. These results demonstrate the great potential of CNF/IRMOF-based TENGs for development of self-powered sensing devices for long-term motion monitoring. Full article