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- 实验方案
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Shape-Deformable Self-Healing Electroluminescence Displays
摘要： Self-healing electronic materials can substantially enhance the lifetime of a device as they can self-repair mechanical damages, thereby recovering their initial electronic performance similar to human skin. Despite the development of various self-healing electronic components such as electrodes and semiconducting carrier transport layers, self-healing electroluminescence (EL) layers suitable for deformable displays, which require both high stretchability and self-recovery function, have been rarely demonstrated. Herein, shape-deformable and self-healing EL displays (SSELDs) are presented. Light-emitting materials are fabricated by adding a certain amount of a plasticizer, Triton X-100, to elastomeric poly(urethane) containing light-emitting Cu-doped ZnS microparticles to obtain a viscoelastic composite that undergoes facile shape-deformation and recovery. A capacitive SSELD exhibits frequency-dependent field-induced light emission under alternating current (AC). Color mixing and tuning of EL is conveniently achieved by mechanically mixing two or more Cu-doped ZnS microparticles with different EL characteristics. More importantly, an SSELD self-recovers its EL within few minutes of electrical failure. Further, the AC EL device endures more than 100 cycles of failure-recovery operations. By combining with a shape-deformable ionic liquid, a novel fiber display that exhibits excellent shape-deformable and self-healing EL performance is demonstrated.
关键词： viscoelastic light-emitting composites,self-healing displays,shape-deformable displays,fiber-type displays,polymer plasticizer,alternating current electroluminescence
更新于2025-09-10 09:29:36
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3.5: Investigation of excited-state dynamics upon both photo- and electro-excitation of thermally activated delayed fluorescent molecules
摘要： Exciton dynamics is one of the core issues lies in the field of achieving high efficiency organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) molecules. The authors briefly review the host dependence of TADF dopant, and then discuess the host–guest interaction in TADF OLEDs. By the means of transient electroluminescence measurement, the dynamics of triplet and singlet excitons are studied. Results show that host material with high T1 energy levels, large spectral overlap with TADF dopant’s absorption and free of exciplex formation exhibits higher TADF character. Furthermore, the underlying reason for the efficiency roll-off of the TADF OLEDs is clarified to be attributed to deeply trapped charges.
关键词： transient,trapped charges,excited-state dynamics,electroluminescence measurement
更新于2025-09-10 09:29:36
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Electroluminescence and contact formation of 1-(pyridin-2-yl)-3-(quinolin-2-yl)imidazo[1,5-a]quinoline thin films
摘要： Contact formation was investigated for the recently introduced organic light emitting molecule 1-(pyridin-2-yl)-3-(quinolin-2-yl)imidazo[1,5-a]quinoline (PCIC) by in situ atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) during physical vapor deposition (PVD). The hole conductors poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(9-vinylcarbazole) (PVK), as well as the electron conductor bathocuproine (BCP) were used. Different growth modes were found for PCIC films and charge carrier injection barriers were identified. Based on these findings, electroluminescent layer structures with an imidazo[1,5-a]quinoline were prepared for the first time and effects of contact formation on radiative recombination were studied. Depending on the chosen contact material, blue PCIC electroluminescence or significantly red-shifted emission presumably caused by electroplex formation could be obtained. Using PCIC in a host-guest system within a matrix of PVK and 1,3-bis[5-(4-tert-butylphenyl)-2-[1,3,4]oxadiazolyl]benzene (Oxd-7), led to blue emission at improved luminescence. The studied interactions of PCIC with typical contact materials reveal the potential and limitations to use PCIC as an electroluminescent material.
关键词： Kelvin probe force microscopy,Electroluminescence,Contact formation,Organic light-emitting diode
更新于2025-09-10 09:29:36
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Magnetic field effect on polaron recombination in conjugated polymers
摘要： By using the one-dimensional tight-binding model, we theoretically investigate the effect of magnetic field on the collision of the oppositely charged polarons with their spin antiparallel in cis-polyacetylene. We adopt the non-adiabatic approach to simulate the dynamical evolution of polaron spin. Under the effect of electric field with a moderate strength, the polarons initially localized at the chain-end of polyacetylene move towards each other. During the collision process, an obvious spin precession is obtained, and the precession period is found to be inversely proportional to the strength of magnetic field. While after including electron-electron interaction in form of Hubbard model, the period is no longer constant. With the decrease of distance between the oppositely charged polarons, the precession of their spin slows down. We also find that there is a critical value of electron-electron interaction strength, over which the spin precession of polaron disappears. In addition, we demonstrate that under the effect of magnetic field, the polarons could recombine or pass through each other to form the singlet exciton, rather than be dissociated after collision between them with the strong electron-electron interaction, and then the electroluminescence efficiency of organic optoelectronic devices is improved.
关键词： polaron,conjugated polymer,Zeeman effect,electron-electron interaction,spin precession,magneto-electroluminescence
更新于2025-09-10 09:29:36
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Raising the Operating Temperature of (Ga,Mn)As/GaAs Spin Light Emitting Diodes by Applying Post-Growth Treatment
摘要： Spin light emitting diodes (spin-LEDs) containing (Ga,Mn)As ferromagnetic layers are fabricated based on InGaAs/GaAs heterostructures and studied. We achieve increases in the operating temperatures of our spin-LEDs by subjecting the surface of the structures, prior to depositing an ohmic metal contact, to pulsed laser annealing. The fabricated devices produce circularly polarized electroluminescence when placed in an external magnetic field. The temperatures at which circularly polarized electroluminescence is still observed is raised from 30 K for unprocessed structure to 110 K for laser-annealed structures. The observed effect is linked to an increase in the Curie temperature of the (Ga,Mn)As layer as a result of laser impact.
关键词： ferromagnetic layers,circularly polarized electroluminescence,Curie temperature,Mn)As,pulsed laser annealing,Spin light emitting diodes,(Ga
更新于2025-09-10 09:29:36
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Investigation of GaN-on-GaN vertical <i>p</i> - <i>n</i> diode with regrown <i>p</i> -GaN by metalorganic chemical vapor deposition
摘要： To mimic selective-area doping, p-GaN was regrown on an etched GaN surface on GaN substrates by metalorganic chemical vapor deposition. Vertical GaN-on-GaN p-n diodes were fabricated to investigate the effects of the etch-then-regrowth process on device performance. The crystal quality of the sample after each epitaxial step was characterized by X-ray diffraction, where the etch-then-regrowth process led to a very slight increase in edge dislocations. A regrowth interfacial layer was clearly shown by transmission electron microscopy. Strong electroluminescence was observed with three emission peaks at 2.2 eV, 2.8 eV, and 3.0 eV. The forward current density increased slightly with increasing temperature, while the reverse current density was almost temperature independent indicating tunneling as the reverse transport mechanism. This result is very similar to the reported Zener tunnel diode comprising a high doping pro?le at the junction interface. High levels of silicon and oxygen concentrations were observed at the regrowth interface with a distribution width of (cid:2)100 nm. This work provides valuable information on p-GaN regrowth and regrown GaN p-n diodes, which can serve as an important reference for developing selective doping for advanced GaN power electronics for high voltage and high power applications.
关键词： electroluminescence,tunneling,GaN,regrowth,p-n diode,metalorganic chemical vapor deposition
更新于2025-09-10 09:29:36
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Recent advances in bubble-assisted Liquid Hole-Multipliers in liquid xenon
摘要： We report on recent advances in the operation of bubble-assisted Liquid Hole-Multipliers (LHM). By con?ning a vapor bubble under or adjacent to a perforated electrode immersed in liquid xenon, we could record both radiation-induced ionization electrons and primary scintillation photons in the noble liquid. Four types of LHM electrodes were investigated: a THGEM, standard double-conical GEM, 50 μm-thick single-conical GEM (SC-GEM) and 125 μm-thick SC-GEM — all coated with CsI photocathodes. The 125 μm-thick SC-GEM provided the highest electroluminescence (EL) yields, up to ～ 400 photons per electron over 4π, with an RMS pulse-height resolution reaching 5.5% for events comprising ～ 7000 primary electrons. Applying a high transfer ?eld across the bubble, the EL yield was further increased by a factor of ～ 5. The feasibility of a vertical-mode LHM, with the bubble con?ned between two vertical electrodes, and the operation of a two-stage LHM con?guration were demonstrated for the ?rst time. We combine electrostatic simulations with observed signals to draw conclusions regarding the location of the liquid-gas interface and suggest an explanation for the observed di?erences in EL yield between the investigated electrodes.
关键词： Micropattern gaseous detectors (MSGC, GEM, THGEM, RETHGEM, MHSP, MICROPIC, MICROMEGAS, InGrid, etc),Noble liquid detectors (scintillation, ionization, double-phase),Charge transport, multiplication and electroluminescence in rare gases and liquids
更新于2025-09-09 09:28:46
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Synthesis of Al-doped CdS/Si nanoheterojunction arrays and their electrical and electroluminescence properties
摘要： The Al-doped CdS/Si nanoheterostructures were prepared by growing Al-doped CdS films on silicon nanoporous pillar array (Si-NPA) through chemical bath deposition (CBD). Their structure, electrical, and electroluminescence properties were investigated as a function of [Al]/[Cd]. At low [Al]/[Cd], Al ions tend to enter the lattice substitutionally, decreasing the lattice constants, micro-strain along (0 0 2) plane, and resistivity, and enhancing average crystallite size and carrier mobility. However, this behavior is reversed at high [Al]/[Cd], because Al ions tend to enter the lattice interstitially. The electroluminescence (EL) properties were most affected by Al doping. As Al concentration increases, the EL intensity initially increased rapidly to a maximum with [Al]/[Cd] and then decreased with further increased [Al]/[Cd]. The maximum of EL intensity was observed in sample S-0.07. Its EL intensity is 320 times that of S-0 and its applied voltages are very low. It could be observed by the naked eyes even at 3 V. These results indicated that Al-doped CdS/Si-NPA might be a great potential in constructing optoelectronic nanodevices. The measured results show the incorporation of suitable amount of Al would improve significantly the performances of CdS/Si-NPA heterojunctions, increasing the uniformity of CdS thin film, decreasing the resistivity, enhancing carrier mobility, improving obviously the rectification behavior, and increasing greatly the EL emission intensity. These results indicated that Al-doped CdS/Si-NPA might be a great potential in constructing optoelectronic nanodevices.
关键词： optoelectronic nanodevices,electrical properties,chemical bath deposition,electroluminescence properties,Al-doped CdS/Si nanoheterostructures
更新于2025-09-09 09:28:46
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Electroluminescence of intrashell transitions in Eu doped single ZnO nanowires
摘要： Tunable nanoscale light emitters are essential to accomplish future multifunctional optoelectronic nano-devices. Here, we present an approach for achieving red electroluminescence from single ZnO nanowires implanted with Europium ions. The electroluminescence is emitted mainly from the end facets of ZnO nanowires at room temperature under the application of an AC voltage. The corresponding electroluminescence spectrum is attributed to the radiative intrashell transitions of the Eu ions, while contributions from near band edge or deep level emission of the ZnO remain absent. The total intensity of the electroluminescence is linearly proportional to the length of the nanowires, whereas there is no clear correlation with other morphology factors of the nanowire based device such as the diameter. Furthermore, the underlying excitation mechanism of the electroluminescence is proposed as direct-impact excitation of Eu ions by hot electrons in the ZnO nanowires.
关键词： electroluminescence,Zinc oxide (ZnO),Europium (Eu),nanowires,rare earth elements,ion beam doping
更新于2025-09-09 09:28:46
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Exciton-Induced Degradation of Hole Transport Layers and Its Effect on the Efficiency and Stability of Phosphorescent Organic Light-Emitting Devices
摘要： The effect of exciton-induced degradation of hole transport layers (HTLs) and its influence on efficiency and stability of phosphorescent organic light emitting devices (PhOLEDs) are investigated. In order to be able to isolate and study the effect of excitons on HTLs, UV illumination as a means to expose them to exciton stress is used. Results reveal that exciton stress of only the HTLs can lead to a significant deterioration in the electroluminescence external quantum efficiency and stability of PhOLEDs, revealing the detrimental role of exciton-induced degradation of HTLs in limiting the device performance. The creation of quenchers in HTLs and the diffusion of excitons from the HTL to the EML appear to play roles in this degradation mechanism. Observations reveal that exciton-induced degradation of HTLs more strongly impacts PhOLEDs than their fluorescent counterparts, revealing the more critical role that HTLs play in influencing their stability and pointing to the role of triplet excitons in this phenomenon. Observations also suggest that increasing the exciton stability of HTLs or reducing exciton lifetime in them can help increase device stability. The findings uncover a new degradation mode in PhOLEDs and provide key insights for device design for realizing better performance and stability.
关键词： electroluminescence efficiency,device stability,phosphorescent OLEDs,exciton-induced degradation,hole transport layers
更新于2025-09-04 15:30:14