- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2020 Moscow Workshop on Electronic and Networking Technologies (MWENT) - Moscow, Russia (2020.3.11-2020.3.13)] 2020 Moscow Workshop on Electronic and Networking Technologies (MWENT) - Measurement of the Dynamic Characteristics of Separate Spectral Bands of the LEDs Electroluminescence Spectra
摘要： A method for measuring the 3 dB frequency of the full modulation of separate spectral components of electroluminescence spectrum of light-emitting diodes (LEDs) is described. The method consists in passing through the LED a series of current pulses having the shape of a meander, and the emission spectrum of the LED is measured by a spectrometer OceanOptics USB2000+ in the mode of signal accumulation. As the pulse frequency increases, the intensity of all spectral components of the LED emission spectrum decreases. The frequency at which the optical signal decreases 1.19 times relative to the level measured at a low frequency is taken as the 3 dB frequency of the separate spectral component of the LED electroluminescence spectrum. By using the pulse signal it is possible to increase the sensitivity of the measuring means compared to the measuring means using the harmonic test signal. A description of the hardware-software complex implementing said measurement method is presented. The results of testing the measuring complex by the electroluminescence spectra of commercial green InGaN-based LEDs at the current range of 10-5...10-2 A and the current frequency range of 0.001...10 MHz are presented. The developed hardware-software complex and the method for estimating the spectral recombination parameters of heterojunction LEDs can be used both for the purpose of diagnosing the quality of LEDs and in developing structural and technological solutions for creating new light-emitting structures.
关键词： electroluminescence spectra,measuring complex,measurement method,3 dB frequency,light-emitting diode (LED),radiative and nonradiative charge carriers lifetime
更新于2025-09-23 15:21:01
-
Pyrene-based hyperbranched porous polymers with doped Ir(piq)2(acac) red emitter for highly efficient white polymer light-emitting diodes
摘要： Here, we designed and prepared a series of hyperbranched porous polymers constructed using fluorene branches and pyrene core, and all hyperbranched porous polymers exhibit intense blue fluorescence, good morphological stability, and high thermal stability. Further, it is found that the aperture sizes for hyperbranched porous polymers can be adjusted by simply changing the content of pyrene and fluorene in the synthesis process. When the feed ratios of pyrene in the total polymers is 15 mol%, the optimized aperture size was obtained, which is slightly larger than the maxlength of complementary red emitter Bis(1-phenylisoquinoline)(acetylacetonate) iridium (III) (Ir(piq)2acac), indicating the Ir(piq)2acac can well distributed in the apertures of hyperbranched porous polymers in co-doped film of Ir(piq)2acac and hyperbranched porous polymers. The fabricated polymer-light-emitting diode (PLED) with such co-doped film as light-emitting layer realizes good white emission with almost equal blue and red emission intensity from hyperbranched porous polymers and Ir(piq)2acac. The balanced electroluminescent (EL) spectra contribute to ideal Commission Internationale de l’Eclairage (CIE) coordinate of (0.326, 0.374) located at white light zone. In addition, the device also achieves high device performance with maximum luminance and current efficiency reaching 5369 cd/m2 and 8.35 cd/A, respectively. We believe that such porous-structure polymers have huge potential applications in the development of highly efficient white PLEDs with reducing production cost.
关键词： White light,Electroluminescence spectra,Polymer light-emitting diodes,Hyperbranched porous polymers
更新于2025-09-16 10:30:52