Nanowerk April 18, 2024 Emerging light-emitting electrochemical cells (LECs) can be cost- and energy-efficiently fabricated by ambient-air printing by virtue of the in situ formation of a p-n junction doping structure. However, the in situ doping transformation renders a meaningful efficiency analysis challenging. Researchers in Sweden have developed a method for separation and quantification of major LEC loss factors, notably the outcoupling efficiency and exciton quenching. They found the shift in the position of the emissive p-n junction in common singlet-exciton emitting LECs to shift markedly with increasing current, and the influence of this shift on the outcoupling efficiency was […]
Category Archives: Light source
Coordination polymer crystals show promise as new generation of light sources for industry, medicine
Phys.org February 20, 2024 Luminescent lanthanide coordination polymer crystals (LCPCs) provide a high level of structural tunability, including size- and morphology-dependent properties; therefore, they are promising materials for next-generation phosphors in a wide range of applications such as light emitting diodes. By controlling the morphology of thermostable europium coordination polymer crystals researchers in Japan developed a novel red phosphor with narrow linewidth emission and characterized them through analysis. Size tunable crystalline polymer spheres had high internal quantum efficiency and high thermostability, and exhibited dispersibility in PMMA Poly(methyl methacrylate) media… read more. Open Access TECHNICAL ARTICLE
Researchers discover new way to generate light through use of pre-existing defects in semiconductor materials
Nanowerk October 26, 2021 InGaN LEDs with considerably high indium concentrations remain difficult to manufacture using conventional semiconductor structures. An international team of researchers (Singapore, USA- MIT) leveraged the the formation of pyramids, the intrinsic defects in LED materials. V-pits, which result from naturally-existing dislocations in the material, directly forms indium-rich quantum dots that emit longer-wavelength light. By growing these structures on conventional silicon substrates, the need for patterning or unconventional substrates is further eliminated. The researchers demonstrated visual confirmation of their morphology. In addition to the formation of quantum dots, the nucleation of stacking faults – another intrinsic crystal […]
A novel approach produces a completely new kind of dynamic light structure
Phys.org August 24, 2020 At a given distance light can dynamically rotate around its center and revolve around another central axis. An international team of researchers (USA – UCSF, Naval Information Warfare Center, University of Rochester, Israel) has shown that combining twisted light and frequency combs together can produce an even more novel structure of light. The beams they simulated achieved mode purity up to 99%, and also had control of the helical phase front. The findings shed insight on our basic understanding of light generation and propagation. This innovation may have future applications in sensing, imaging, manufacturing, and metrology. […]
On-chip light source produces versatile range of wavelengths
Science Daily December 19, 2019 A team of researchers in the US (NIST, University of Maryland, Carnegie Mellon University) has created visible light from an infrared pump by widely separated optical parametric oscillation (OPO) using silicon nanophotonics. The OPO creates signal and idler light in the 700 nm and 1300 nm bands, respectively, with a 900 nm pump. It operates at a threshold power of (0.9±0.1)mW, over 50× smaller than other widely separated microcavity OPO works, which have been reported only in the infrared. This low threshold enables direct pumping without need of an intermediate optical amplifier. The device design […]