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Liu, Minne (author), Li, Wenyu (author), Chen, Wei (author), Ibrahim, Mesfin S. (author), Xiong, Jingkang (author), Zhang, Kouchi (author), Fan, Jiajie (author)During the operation of an LED array, its thermal and optical performances are always not equal to the superposition of the individual LED's characteristics because of a significant thermal coupling effect between the arrays. Based on this, this paper proposes an electrical–photo-thermal model, with considering both junction temperature and...journal article 2024
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Wen, Minzhen (author), Ibrahim, Mesfin Seid (author), Meda, Abdulmelik Husen (author), Zhang, Kouchi (author), Fan, J. (author)High-power white light-emitting diodes (LEDs) have demonstrated superior efficiency and reliability compared to traditional white light sources. However, ensuring maximum performance for a prolonged lifetime use presents a significant challenge for manufacturers and end users, especially in safety–critical applications. Thus, identifying...journal article 2024
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Rocchetta, Roberto (author), Zhan, Zhouzhao (author), van Driel, W.D. (author), Di Bucchianico, Alessandro (author)Lifetime analyses are crucial for ensuring the durability of new Light-emitting Diodes (LEDs) and uncertainty quantification (UQ) is necessary to quantify a lack of usable failure and degradation data. This work presents a new framework for predicting the lifetime of LEDs in terms of lumen maintenance, effectively quantifying the natural...journal article 2024
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Zhu, Yifan (author), Lu, Huimin (author), Wang, Jianping (author), Yu, Tongjun (author), Li, Z.Z.L. (author), Tian, Yucheng (author)In order to improve the light extraction of AlGaN-based short wavelength ultraviolet light emitting diodes (DUC-LEDs), a type of microstructure with high aspect ratio is introduced and optimized on the AlN substrate surface. And, particle swarm optimization (PSO) algorithm is used to inverse design of the surface microstructure to maximize...journal article 2023
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Laursen, Kjeld (author), Zamani, M. (author), Rezaeiyan, Y. (author), Hosseini, Seyedsina (author), Mondal, Tanmay (author), Corbett, Brian (author), Ouagazzal, Abdel Mouttalib (author), Amalric, Marianne (author), Moradi, Farshad (author)This brief presents an ultrasonically powered micro-system for deep tissue optogenetic stimulation. The developed system is composed of a Base for Powering and Controlling (BPC) and an implantable Dust for optogenetics and drug delivery. The Dust consists of a piezoelectric crystal, a rectifier chip, and a micro-scale custom-designed light...journal article 2023
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Liu, Shuoyan (author), Xue, Bing (author), Yan, Wenyuan (author), Rwei, A.Y. (author), Wu, Changsheng (author)With a growing focus on properties of softness, miniaturization, and intelligence, extensive research has been focusing on constructing wearable electronic devices facilitating comfort, wearable health monitoring and diagnosis. Among recent progress in the development of wearable bioelectronics, wearable near-infrared spectroscopy (NIRS)...journal article 2023
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Herzog, Alexander (author), Benkner, Simon (author), Zandi, Babak (author), Buffolo, Matteo (author), van Driel, W.D. (author), Meneghini, Matteo (author), Khanh, Tran Quoc (author)We report on the degradation mechanisms and dynamics of silicone encapsulated ultraviolet A (UV-A) high-power light-emitting diodes (LEDs), with a peak wavelength of 365nm. The stress tests were carried out for a period of 8665 hours with forward currents between 350mA and 700mA and junction temperatures up to 132°C. Depending on stress...journal article 2023
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Benkner, Simon (author), Herzog, Alexander (author), Klir, Stefan (author), van Driel, W.D. (author), Khanh, Tran Quoc (author)The unique radiative, photometric and colorimetric characteristic of a light-emitting diode is derived from its spectral power distribution. Modeling such characteristics with respect to the forward current, temperature or operating time has been subject of various studies. Deriving a simple analytical model, however, is not trivial due to the...journal article 2022
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Dutta, S. (author), Steeneken, P.G. (author), Verbiest, G.J. (author)Small and low-cost chlorophyll sensors are popular in agricultural sector and food-quality control.Combining such sensors with silicon CMOS electronics is challenged by the absence of silicon-integrated light-sources.We experimentally achieve optical absorption sensing of chlorophyll based pigments with silicon (Si) micro light-emitting...journal article 2022
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Herzog, Alexander (author), Wagner, Max (author), Benkner, Simon (author), Zandi, Babak (author), van Driel, W.D. (author), Khanh, Tran Quoc (author)We report on the degradation dynamics and mechanisms of the commercially available chip-on-board (COB) high-power light-emitting diode (LED) modules with an electrical power of 175 W. Due to the associated thermal load, the temperature dependence of the aging processes is additionally analyzed within the scope of this work. The aging tests...journal article 2022
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Cao, Yixing (author), Chen, Wei (author), Du, Yunjia (author), Qi, Gaojin (author), Santos, Thebano (author), Zhang, Kouchi (author), Fan, J. (author)YAG: Ce3+ phosphor/silicone composites are widely used in solid-state lighting as a light converter to achieve white lighting. However, because of high thermal resistance and low thermal stability, the luminous performance of YAG: Ce3+ phosphor/silicone composite deteriorates rapidly when excited by high-power-density blue-laser. To explore...journal article 2022
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Teo, Ying Shen (author), Jafari, Iman (author), Liang, Fei (author), Jung, Youmi (author), van der Hoek, J.P. (author), Ong, Say Leong (author), Hu, Jiangyong (author)The UV/Cl2 process (also known as chlorine photolysis, which is the combination of chlorine and simultaneous irradiation of UV light) is conventionally applied at acidic mediums for drinking water treatment and further treatment of wastewater effluents for secondary reuse. This is because the quantum yield of HO• from HOCl (ϕHO•, 254 = 1.4) is...journal article 2022
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Hueting, R. J.E. (author), De Vries, H. (author), Dutta, S. (author), Annema, A. J. (author)The CMOS silicon avalanche-mode light-emitting diode (AMLED) has emerged as a potential light source for monolithic optical interconnects. Earlier we presented a superjunction light-emitting diode (SJLED) that offers a higher electroluminescent intensity compared to a conventional AMLED because of its more uniform field distribution. However,...journal article 2021
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Fan, J. (author), Jing, Zhou (author), Cao, Yixing (author), Ibrahim, Mesfin Seid (author), Li, Min (author), Fan, Xuejun (author), Zhang, Kouchi (author)With their advantages of high efficiency, long lifetime, compact size and being free of mercury, ultraviolet light-emitting diodes (UV LEDs) are widely applied in disinfection and purification, photolithography, curing and biomedical devices. However, it is challenging to assess the reliability of UV LEDs based on the traditional life test or...journal article 2021
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He, Cyuan Lun (author), Liang, Fang Cheng (author), Veeramuthu, Loganathan (author), Cho, Chia Jung (author), Benas, Jean Sebastien (author), Tzeng, Yung Ru (author), Tseng, Yen Lin (author), Chen, Wei Cheng (author), Rwei, A.Y. (author), Kuo, Chi Ching (author)Self-healing soft electronic material composition is crucial to sustain the device long-term durability. The fabrication of self-healing soft electronics exposed to high moisture environment is a significant challenge that has yet to be fully achieved. This paper presents the novel concept of a water-assisted room-temperature autonomous self...journal article 2021
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Ibrahim, Mesfin Seid (author), Fan, J. (author), Yung, Winco K.C. (author), Jing, Zhou (author), Fan, Xuejun (author), van Driel, W.D. (author), Zhang, Kouchi (author)The increased system complexity in electronic products brings challenges in a system level reliability assessment and lifetime estimation. Traditionally, the graph model-based reliability block diagrams (RBD) and fault tree analysis (FTA) have been used to assess the reliability of products and systems. However, these methods are based on...journal article 2021
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Dutta, S. (author), Steeneken, P.G. (author), Verbiest, G.J. (author)Silicon p-n junction diodes emit low-intensity, broad-spectrum light near 1120 nm in forward bias and between 400-900 nm in reverse bias (avalanche). For the first time, we experimentally achieve optical absorption sensing of pigment in solution with silicon micro LEDs designed in a standard silicon-on-insulator CMOS technology. By driving a...conference paper 2020
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Fan, J. (author), Wu, Jie (author), Jiang, Changzhen (author), Zhang, H. (author), Ibrahim, M.S. (author), Deng, Liang (author)To make the light-emitting diode (LED) more compact and effective, the flip chip solder joint is recommended in LED chip-scale packaging (CSP) with critical functions in mechanical support, heat dissipation, and electrical conductivity. However, the generation of voids always challenges the mechanical strength, thermal stability, and...journal article 2020
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Dong, Jianfei (author), Wang, T. (author)Light therapies can be used to treat fungal infections. A general mechanism is attributed to the generation of cytotoxic reactive oxygen species (ROS) due to light stimulation. The effectiveness of these therapies has been widely studied in the literature via conducting biological experiments, where fungi are exposed to light with various...journal article 2020
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Yazdan Mehr, M. (author), Bahrami, A. (author), van Driel, W.D. (author), Fan, X.J. (author), Davis, J.L. (author), Zhang, Kouchi (author)In this paper, degradation mechanisms of optical materials, used in the light emitting diode (LED)-based products, are reviewed. The LED lighting is one of the fastest technology shifts in human history. Lighting accounts for almost 20% of the global electrical energy use, inferring that replacement of traditional lighting sources with LEDs...journal article 2020