- 标题
- 摘要
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- 实验方案
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Design of hole transport type host for stable operation in blue organic light-emitting diodes
摘要： Molecular design of the hole transport type host for mixed host was investigated to improve the lifetime of the phosphorescent organic light-emitting diodes. A negative polaron stabilizing hole transport type host design was employed and the effect of the negative polaron stabilizing unit was investigated. Dibenzofuran or benzonitrile was introduced as the negative polaron stabilizing unit in the bicarbazole backbone structure of the hole transport type host. Two host materials were synthesized and the comparison of them proposed that the negative polaron stabilizing unit is a key to the lifetime of the phosphorescent organic light-emitting diodes. The dibenzofuran and benzonitrile embedded bicarbazole hosts performed better than the mCBP host. The dibenzofuran and benzonitrile modified bicarbazole hosts demonstrated high external quantum efficiency of 18.6 and 19.1%, respectively and lifetime extension by 30% compared with the conventional host without the negative polaron stabilizing unit.
关键词： Negative polaron,Lifetime,Mixed host,Hole type host
更新于2025-09-23 15:21:01
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Aromatic amine passivated TiO2 for dye-sensitized solar cells (DSSC) with ~9.8% efficiency
摘要： In this work, the e?ciency of dye-sensitized solar cells (DSSC) was improved by capping TiO2 with simple aromatic amines as a complexing agent. The aromatic amines, aniline and o-phenylenediamine capped TiO2 composites were synthesized via hydrothermal route and used as scattering layer in dye-sensitized solar cell (DSSC). Markedly, the maximum photo-conversion e?ciency of 9.84% was achieved with o-phenylenediamine capped-TiO2 composite as o-phenylenediamine capped-TiO2 showed higher re?ectivity than the pristine TiO2, which is highly bene?cial for re?ecting the photons back to photoanode. In addition, the average life time of carriers in o-phenylenediamine capped-TiO2 was found to be 9.8 ms, which was 2 times higher than the pristine TiO2 (4.29 ms).
关键词： Aromatic amines,DSSC,Scattering layer,Electron injection,TiO2,Lifetime
更新于2025-09-23 15:21:01
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Effect of illumination on quantum lifetime in GaAs quantum wells
摘要： Low-temperature illumination of a two-dimensional electron gas in GaAs quantum wells is known to greatly improve the quality of high-field magnetotransport. The improvement is known to occur even when the carrier density and mobility remain unchanged, but what exactly causes it remains unclear. Here, we investigate the effect of illumination on microwave photoresistance in low magnetic fields. We find that the amplitude of microwave-induced resistance oscillations grows dramatically after illumination. Dingle analysis reveals that this growth reflects a substantial increase in the single-particle (quantum) lifetime, which likely originates from the light-induced redistribution of charge enhancing the screening capability of the doping layers.
关键词： quantum lifetime,microwave photoresistance,GaAs quantum wells,illumination effect,two-dimensional electron gas
更新于2025-09-23 15:21:01
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Minority carrier lifetime and diffusion length in type II superlattice barrier devices
摘要： The minority carrier lifetime in p-type InAs/GaSb type II superlattices (T2SLs) is quite short, typically in the region of tens of nanoseconds. In spite of this, T2SLs are becoming a viable alternative to Mercury Cadmium Telluride as the sensing material of choice for high end MWIR and LWIR infrared detectors. For example, SCD now manufactures a 640 × 512 format, 15 μm pitch LWIR focal plane array detector, with a quantum e?ciency close to 50%, a pixel operability of > 99.5%, and a dark current only about one order of magnitude larger than the state of the art Rule 07 value. A key to the very high performance of this detector is the use of an XBp barrier architecture that both suppresses the G-R current and allows stable passivation to all steps of the fabrication process. Since both the dark-current and photo-current in the XBp structure are di?usion limited, measurements of these quantities as a function of the device dimension provide an excellent vehicle for estimating the minority carrier lifetime and di?usion length, when performed in conjunction with k?p calculations of the T2SL density of states. Typical lifetime results are presented, which are consistent with values found by others using direct measurements. Di?usion lengths are reported in the range 3–7 μm, although these are not necessary limiting values.
关键词： Type II superlattice,Infrared detector,XBp detector,Di?usion length,InAs/GaSb superlattice,K?p model,Lifetime,Bariode
更新于2025-09-23 15:21:01
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Fluorescent Nanodiamonds || Producing Fluorescent Nanodiamonds
摘要： Natural diamonds in colors are commonly known as fancies, or fancy color diamonds, in gemstone industries. They are rare, beautiful, and some even carry impressive price tags in the jewelry market. By comparison, micro‐ and nanoscale diamond powders are low in price, with or without colors and fluorescent or not. These powders have been used as abrasives for grinding and polishing purposes since ancient time, mainly because of their extraordinary hardness. Little or no attention has been paid over the centuries to other properties of nanodiamonds such as their innate biocompatibility and light‐emitting capability. The invention of fluorescent nanodiamond (FND) in 2005 has revolutionized the field, opening a new area of research and development with diamonds. Experiments with FNDs in the last decade have demonstrated various promising applications of surface‐functionalized FNDs in diversified fields, ranging from physics and chemistry to biology and medicine. It is worthy of noting that as originated from the discovery of Radium by Marie Sk?odowska Curie (Section 3.2), FNDs may very well be called Madame Curie’s gemstones, valued appropriately as a scientist’s best friend.
关键词： fluorescent nanodiamonds,magnetically modulated fluorescence,fluorescence lifetime,size reduction,FND,ion irradiation,H3 centers,nitrogen-vacancy centers,electron irradiation,NV centers
更新于2025-09-23 15:21:01
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Increasing fluorescence lifetime for resolution improvement in STED nanoscopy
摘要： Super-resolution microscopy (SRM) has had a substantial impact on the biological sciences due to its ability to observe tiny objects less than 200 nm in size. Stimulated emission depletion (STED) microscopy represents a major category of these SRM techniques that can achieve diffraction-unlimited resolution based on a purely optical modulation of fluorescence behaviors. Here, we investigated how the laser beams affect fluorescence lifetime in both confocal and STED imaging modes. The results showed that with increasing illumination time, the fluorescence lifetime in two kinds of fluorescent microspheres had an obvious change in STED imaging mode, compared that in confocal imaging mode. As a result, the reduction of saturation intensity induced by the increase of fluorescence lifetime can improve the STED imaging resolution at the same depletion power. The phenomenon was also observed in Star635P labeled human Nup153 in fixed HeLa cells, which can be treated as a reference for the synthesis of fluorescent labels with the sensitivity to the surrounding environment for resolution improvement in STED nanoscopy.
关键词： confocal microscopy,super-resolution,fluorescence lifetime,fluorescence microscopy
更新于2025-09-23 15:21:01
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[IEEE 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Brasov, Romania (2019.11.3-2019.11.6)] 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Analysis on Hotspot Technologies and Cutting-edge Technologies of Organic Solar Cells Based on Patent Data
摘要： In this letter, we investigate the residual link lifetime (RLL) in a mobile ad hoc network, such as a vehicular network. Although, owing to the underlying mobility of the network nodes, the RLLs of adjacent links are highly correlated, yet previous works typically neglected such correlation. In contrast, our study is based on an accurate modeling of the relative distances and speeds between neighboring mobile nodes. Firstly, a scenario is presented that demonstrates the dependence of RLLs of two adjacent links. We then derive the joint probability distribution of the RLLs of two adjacent links in terms of their parameters. Our model shows that neglecting the correlation between adjacent links results in serious overestimation of the path’s lifetime. Simulation is used to verify our model.
关键词： MANET,residual link lifetime,link lifetime prediction,path lifetime prediction
更新于2025-09-23 15:19:57
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Layer-dependent signatures for exciton dynamics in monolayer and multilayer WSe2 revealed by fluorescence lifetime imaging measurement
摘要： Two-dimensional (2D) transition-metal dichalcogenide (TMD) materials have aroused noticeable interest due to their distinguished electronic and optical properties. However, little is known about their complex exciton properties together with the exciton dynamics process which have been expected to influence the performance of optoelectronic devices. The process of fluorescence can well reveal the process of exciton transition after excitation. In this work, the room-temperature layer-dependent exciton dynamics properties in layered WSe2 are investigated by the fluorescence lifetime imaging microscopy (FLIM) for the first time. This paper focuses on two mainly kinds of excitons including the direct transition neutral excitons and trions. Compared with the lifetime of neutral excitons (< 0.3 ns within four-layer), trions possess a longer lifetime (~ 6.6 ns within four-layer) which increases with the number of layers. We attribute the longer-lived lifetime to the increasing number of trions as well as the varieties of trion configurations in thicker WSe2. Besides, the whole average lifetime increases over 10% when WSe2 flakes added up from monolayer to four-layer. This paper provides a novel tuneable layer-dependent method to control the exciton dynamics process and finds a relatively longer transition lifetime of trions at room temperature, enabling to investigate in the charge transport in TMD-based optoelectronics devices in the future.
关键词： two-dimensional (2D) WSe2,fluorescence lifetime,fluorescence lifetime imaging microscopy (FLIM),exciton dynamics,density functional theory (DFT)
更新于2025-09-23 15:19:57
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Lifetime-weighted photoacoustic imaging
摘要： Photoacoustic (PA) imaging has been utilized to quantify the lifetime profile of exogenous agents using a series of pump-probe pulses with a varying time delay; however, current techniques typically lead to long acquisition times which are sensitive to motion and cause absorption or photobleaching. We introduce a technique called lifetime-weighted imaging, which uses only three laser pulses to preferentially weight signals from chromophores with long lifetimes (including exogenous contrast agents with triplet excited states such as methylene blue and porphyrins) while nulling chromophores with short picosecond- to nanosecond-scale lifetimes (including hemoglobin). This technique detects the PA signal from a probe pulse either with or without a pump pulse. By subtracting the probe-only signal from the pump-present probe signal, we effectively eliminate signals from chromophores with short lifetimes while preserving PA signals from chromophores with long-lifetimes. We demonstrate the oxygen-dependent lifetime of both methylene blue and porphyrin-lipids and demonstrate both ground-state recovery and excited-state lifetime-weighted imaging. Lifetime-weighted PA imaging may have applications in many molecular imaging application including: photodynamic therapy dosimetry guidance and oxygen sensing.
关键词： methylene blue,lifetime-weighted,photoacoustic microscopy,porhpyrins,lifetime
更新于2025-09-23 15:19:57
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Examination of relationship between Urbach energy and open-circuit voltage deficit of flexible Cu(In,Ga)Se <sub/>2</sub> solar cell for its improved photovoltaic performance
摘要： Flexible Cu(In,Ga)Se2 (CIGSe) solar cells on stainless steel (SUS) substrates are developed. The contribution concentrates on the investigation of the correlation between Urbach energy (EU) and open-circuit voltage deficit (VOC,def). The several CIGSe solar cells on soda-lime glass and SUS substrates with various VOC,def values are fabricated through the variations of [Ga]/([Ga]+[In]) ratio (GGI), substrate temperature (TSUB) and Fe concentration of their CIGSe absorbers. The EU is determined based on external quantum efficiency in the long-wavelength edge. It is determined that the EU is influenced by the GGI, TSUB and Fe concentration. The EU is well consistent with the carrier lifetimes and can be an indicator of the CIGSe quality. In addition, the relationship between EU and VOC,def is obviously observed, where the decrease in the EU by 1 meV reduces the VOC,def by 8.6 mV. Through the optimizations of GGI and TSUB as well as the minimization of Fe concentration, the EU is obviously reduced, which implies the improvement of the CIGSe quality. Ultimately, the high η of 17.9% for the flexible CIGSe solar cell on SUS substrate is attained.
关键词： Cu(In,Ga)Se2,stainless steel substrate,TRPL carrier lifetime,Urbach energy,open-circuit voltage deficit
更新于2025-09-23 15:19:57