Efficient lighting is needed for sustainable architecture. As of 2011, some LED bulbs provide up to 150lm/W and even inexpensive low-end models typically exceed 50lm/W, so that a 6-watt LED could achieve the same results as a standard 40-watt incandescent bulb. The lower heat output of LEDs also reduces demand on air conditioning systems. Worldwide, LEDs are rapidly adopted to displace less effective sources such as incandescent lamps and CFLs and reduce electrical energy consumption and its associated emissions. Solar powered LEDs are used as street lights and in architectural lighting. Aerosolized biological particles fluoresce and scatter light under a UV light beam. Observed fluorescence is dependent on the applied wavelength and the biochemical fluorophores within the biological agent. UV induced fluorescence offers a rapid, accurate, efficient and logistically practical way for biological agent detection. This is because the use of UV fluorescence is reagentless, or a process that does not require an added chemical to produce a reaction, with no consumables, or produces no chemical byproducts. [184] functional LED side marker, left, short rubber arm (hanging version), 2×0.75 mm² cable 0.5 m long with QS075 connector. The first blue-violet LED using magnesium-doped gallium nitride was made at Stanford University in 1972 by Herb Maruska and Wally Rhines, doctoral students in materials science and engineering. [39] [40] At the time Maruska was on leave from RCA Laboratories, where he collaborated with Jacques Pankove on related work. In 1971, the year after Maruska left for Stanford, his RCA colleagues Pankove and Ed Miller demonstrated the first blue electroluminescence from zinc-doped gallium nitride, though the subsequent device Pankove and Miller built, the first actual gallium nitride light-emitting diode, emitted green light. [41] [42] In 1974 the U.S. Patent Office awarded Maruska, Rhines, and Stanford professor David Stevenson a patent for their work in 1972 (U.S. Patent US3819974 A). Today, magnesium-doping of gallium nitride remains the basis for all commercial blue LEDs and laser diodes. In the early 1970s, these devices were too dim for practical use, and research into gallium nitride devices slowed.

a b Sun, Changjiu; Jiang, Yuanzhi; Cui, Minghuan; Qiao, Lu; Wei, Junli; Huang, Yanmin; Zhang, Li; He, Tingwei; Li, Saisai; Hsu, Hsien-Yi; Qin, Chaochao; Long, Run; Yuan, Mingjian (April 13, 2021). "High-performance large-area quasi-2D perovskite light-emitting diodes". Nature Communications. 12 (1): 2207. doi: 10.1038/s41467-021-22529-x. ISSN 2041-1723. PMC 8044177. PMID 33850141. GaN-based blue light emitting device development by Akasaki and Amano" (PDF). Takeda Award 2002 Achievement Facts Sheet. The Takeda Foundation. April 5, 2002 . Retrieved November 28, 2007. Scottish Highlands & Islands postcodes: AB, FK, HS, IV, KA, KW, PA, PH, ZE, LL58-LL78, IM, TR, PO30-41Thermal runaway: Parallel strings of LEDs will not share current evenly due to the manufacturing tolerances in their forward voltage. Running two or more strings from a single current source may result in LED failure as the devices warm up. If forward voltage binning is not possible, a circuit is required to ensure even distribution of current between parallel strands. [165] The 'whiteness' of the light produced is engineered to suit the human eye. Because of metamerism, it is possible to have quite different spectra that appear white. The appearance of objects illuminated by that light may vary as the spectrum varies. This is the issue of color rendition, quite separate from color temperature. An orange or cyan object could appear with the wrong color and much darker as the LED or phosphor does not emit the wavelength it reflects. The best color rendition LEDs use a mix of phosphors, resulting in less efficiency and better color rendering. [ citation needed] Aluminium gallium nitride (AlGaN) of varying Al/Ga fraction can be used to manufacture the cladding and quantum well layers for ultraviolet LEDs, but these devices have not yet reached the level of efficiency and technological maturity of InGaN/GaN blue/green devices. If unalloyed GaN is used in this case to form the active quantum well layers, the device emits near-ultraviolet light with a peak wavelength centred around 365nm. Green LEDs manufactured from the InGaN/GaN system are far more efficient and brighter than green LEDs produced with non-nitride material systems, but practical devices still exhibit efficiency too low for high-brightness applications. [ citation needed] LEDs have many advantages over incandescent light sources, including lower power consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. In exchange for these generally favorable attributes, disadvantages of LEDs include electrical limitations to low voltage and generally to DC (not AC) power, inability to provide steady illumination from a pulsing DC or an AC electrical supply source, and lesser maximum operating temperature and storage temperature. UV-C wavelengths were obtained in laboratories using aluminium nitride (210nm), [93] boron nitride (215nm) [94] [95] and diamond (235nm). [96] White LEDs [ edit ]

Zheludev, N. (2007). "The life and times of the LED: a 100-year history" (PDF). Nature Photonics. 1 (4): 189–192. Bibcode: 2007NaPho...1..189Z. doi: 10.1038/nphoton.2007.34. Archived from the original (PDF) on May 11, 2011 . Retrieved April 11, 2007. a b c Liu, Yuan; Dong, Yitong; Zhu, Tong; Ma, Dongxin; Proppe, Andrew; Chen, Bin; Zheng, Chao; Hou, Yi; Lee, Seungjin; Sun, Bin; Jung, Eui Hyuk; Yuan, Fanglong; Wang, Ya-kun; Sagar, Laxmi Kishore; Hoogland, Sjoerd (September 29, 2021). "Bright and Stable Light-Emitting Diodes Based on Perovskite Quantum Dots in Perovskite Matrix". Journal of the American Chemical Society. 143 (38): 15606–15615. doi: 10.1021/jacs.1c02148. ISSN 0002-7863. PMID 34542273. S2CID 237574321. functional LED side marker, right, long, slanted rubber arm, 2×0.75 mm² cable 0.5 m long with QS075 connector. You can also select a convenient day to receive your delivery by choosing a named day delivery (delivery on working days only). Ohno, Y. (2004). Ferguson, Ian T; Narendran, Nadarajah; Denbaars, Steven P; Carrano, John C (eds.). "Color rendering and luminous efficacy of white LED spectra" (PDF). Proc. SPIE. Fourth International Conference on Solid State Lighting. 5530: 89. Bibcode: 2004SPIE.5530...88O. doi: 10.1117/12.565757. S2CID 122777225. Archived from the original (PDF) on May 11, 2011.

Alex - a functional and flexible LED desk lamp

Nakamura, S.; Mukai, T.; Senoh, M. (1994). "Candela-Class High-Brightness InGaN/AlGaN Double-Heterostructure Blue-Light-Emitting-Diodes". Applied Physics Letters. 64 (13): 1687. Bibcode: 1994ApPhL..64.1687N. doi: 10.1063/1.111832. Find sources: "Light-emitting diode"– news · newspapers · books · scholar · JSTOR ( October 2020) ( Learn how and when to remove this template message)