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Low Power Consumption Red Light-Emitting Diodes Based on Inorganic Perovskite Quantum Dots under an Alternating Current Driving Mode
摘要： Inorganic perovskites have emerged as a promising candidate for light-emitting devices due to their high stability and tunable band gap. However, the power consumption and brightness have always been an issue for perovskite light-emitting diodes (PeLEDs). Here, we improved the luminescence intensity and decreased the current density of the PeLEDs based on CsPbI3 quantum dots (QDs) and p-type Si substrate through an alternating current (AC) driving mode. For the different driving voltage modes (under a sine pulsed bias or square pulsed bias), a frequency-dependent electroluminescent (EL) behavior was observed. The devices under a square pulsed bias present a stronger EL intensity under the same voltage due to less thermal degradation at the interface. The red PeLEDs under a square pulsed bias driving demonstrate that the EL intensity drop-off phenomenon was further improved, and the integrated EL intensity shows the almost linear increase with the increasing driving voltage above 8.5 V. Additionally, compared to the direct current (DC) driving mode, the red PeLEDs under the AC condition exhibit higher operating stability, which is mainly due to the reducing accumulated charges in the devices. Our work provides an effective approach for obtaining strong brightness, low power consumption, and high stability light-emitting devices, which will exert a profound in?uence on coupling LEDs with household power supplies directly.
关键词： low power consumption,perovskite quantum dots,silicon,light emitting diodes,alternating current driving
更新于2025-11-21 11:01:37
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The effect of alternating current on the current states of a quantum interferometer shunted by a superconducting inductance
摘要： The patterns of reversible changes in the critical current and discrete current states of a structure in the form of a superconducting quantum interferometer shunted by superconducting inductance, as a result of passing an alternating transport current through the structure and applying an external alternating magnetic field simultaneously with a direct transport current, was established. A new type of discrete stationary state was discovered during the transition of the interferometer to the resistive state caused by the combined action of direct and alternating transport currents.
关键词： resistive state,superconducting inductance,alternating current,superconducting quantum interferometer,discrete current states
更新于2025-09-23 15:21:21
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Alternating Current Photovoltaic Effect
摘要： It is well known that the photovoltaic effect produces a direct current (DC) under solar illumination owing to the directional separation of light-excited charge carriers at the p–n junction, with holes flowing to the p-side and electrons flowing to the n-side. Here, it is found that apart from the DC generated by the conventional p–n photovoltaic effect, there is another new type of photovoltaic effect that generates alternating current (AC) in the nonequilibrium states when the illumination light periodically shines at the junction/interface of materials. The peak current of AC at high switching frequency can be much higher than that from DC. The AC cannot be explained by the established mechanisms for conventional photovoltaics; instead, it is suggested to be a result of the relative shift and realignment between the quasi-Fermi levels of the semiconductors adjacent to the junction/interface under the nonequilibrium conditions, which results in electron flow in the external circuit back and forth to balance the potential difference between two electrodes. By virtue of this effect, the device can work as a high-performance broadband photo detector with extremely high sensitivity under zero bias; it can also work as a remote power source providing extra power output in addition to the conventional photovoltaic effect.
关键词： nonthermal equilibrium state,quasi-Fermi levels,excessive carriers,AC photovoltaic effect,photovoltaic effect,alternating current
更新于2025-09-19 17:13:59
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Enhanced dielectric and piezoelectric properties in the [001]-poled 0.25Pb(In <sub/>1/2</sub> Nb <sub/>1/2</sub> )O <sub/>3</sub> -0.43Pb(Mg <sub/>1/3</sub> Nb <sub/>2/3</sub> )O <sub/>3</sub> -0.32PbTiO <sub/>3</sub> single crystal near morphotropic phase boundary by alternating current treatment
摘要： In this paper, temperature dependance of induced dielectric and piezoelectric properties in the [001]-oriented predirect current poling (DCP) of the 0.25Pb(In1/2Nb1/2)O3-0.43Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 (0.25PIN-0.43PMN-0.32PT) single crystals near morphotropic phase boundary was investigated using the alternating current treatment (ACT). By the optimized ACT conditions of 1 kV/mm at 50 Hz over 20 cycles, the dielectric permittivity (ε0) and piezoelectric coefficient (d33) at room temperature of the DCP-ACT crystal were improved to be 7120 and 2610 pC/N, which were 48% and 54% higher than that of the DCP crystal (ε0 = 4800, d33 = 1700 pC/N). Based on the temperature dependence of dielectric permittivity and dielectric loss of the DCP-ACT crystal, the induced monoclinic phases (MA and MC) were involved in the phase transition process from a rhombohedral phase to a tetragonal phase. The phase transition temperatures TR-MA of 116 °C of the DCP-ACT crystal showed about 10 °C higher than that of DCP. Meanwhile, ε0 of the DCP-ACT crystal at TR-MA and in the tetragonal phase region, at around 110 °C and 130 °C, were 160% and 390% higher than those of the DCP crystal, respectively. The ultrahigh ε0 = 17 000 of the DCP-ACT crystal at 130 °C may relate to the nanoscale heterogeneous polar-regions induced by ACT. The ACT is a promising way to enhance the dielectric and piezoelectric performance of the pre-DCP 0.25PIN-0.43PMN-0.32PT single crystals with broadened temperature range for device applications.
关键词： single crystal,piezoelectric properties,morphotropic phase boundary,alternating current treatment,dielectric properties
更新于2025-09-19 17:13:59
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Tunable Assembly of Superfine Single-Walled Carbon Nanotube Fibers
摘要： We have developed a method of spinning super?ne single-walled carbon nanotube (SWNT) ?bers to facilitate their assembly in 2D counter microelectrode array via alternating current (AC) dielectrophoresis (DEP) by using clean, combination of ionic surfactants, and stable SWNT aqueous high-quality solutions. Our method can attract metallic SWNTs (M_SWNTs) toward a counter microelectrode array, resulting in an opposite movement of semiconducting SWNTs (S_SWNTs) and leaving S_SWNTs in the suspension by taking advantages of the differences in the relative dielectric constants of M_SWNTs and S_SWNTs with respect to the suspension and substrate-bent AC DEP structure. Our method can also control the stretching or relaxed extent and diameters of the suspended SWNT ?bers by tuning the bending degree of a ?exible substrate, AC frequency, peak value of AC voltage, and time. The effectiveness of the method is proven by the electrical measurement result, scanning electron microscopy image, atomic force microscope image and Raman spectroscopy on test samples.
关键词： Tunable assembly,single-walled carbon nanotube (SWNT) ?bers,alternating current (AC) dielectrophoresis,substrate-bent
更新于2025-09-16 10:30:52
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[IEEE 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - Pune, India (2018.8.29-2018.8.31)] 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - New Control Technique to Improve the Grid Power by Using PV-STATCOM
摘要： This paper introduces novel control method to utilize the solar plant inverter as static synchronous compensator (STATCOM) which is also called as PV-STATCOM to improve the power transmission capacity of the grid. The solar farm is ideal for the nighttime and it produces less power in morning period and late afternoon period. Therefore these are the expensive assets which are remaining unutilized during this period of 24hrs. To overcome these problems solar plant along with maximum power point tracking [MPPT] produces active power during daytime and full capacity of solar plant inverter which is not used in night period is used with help of point of common coupling [PCC] voltage controller and damping controller to improve the power transmission capacity of line and also power factor of the grid line. The inverter capacity which is left after the real power generation is used to perform the given objective. This new control technique is used to increase the grid transfer capacity for which other alternatives are used like FACT devices.
关键词： flexible alternating current transmission system,inverter,solar system,damping controller,MPPT,STATCOM,dc voltage regulator,voltage controller
更新于2025-09-10 09:29:36
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In-Planar-Electrodes Organic Light-Emitting Devices for Smart Lighting Applications
摘要： Smart lighting systems have earned an irreplaceable position in fields such as health care, communication, and garden cultivation. Inorganic light-emitting diode (LED) illuminant, as a traditional and well-developed field, is suitable for smart lighting systems and widely researched. However, smart lighting systems with organic light-emitting device (OLED) illuminant are rare. The key issue is to fabricate an efficient OLED illuminant with tunable spectra and intensity. Here, in-planar-electrodes OLEDs (IPE-OLEDs), which could be a possible solution to OLED illuminant used in smart lighting systems, is presented. By utilizing Mg:Ag thin film to connect two regular OLEDs with novel electron transporting layer, efficient and easy-to-fabricate IPE-OLEDs with high brightness and low voltage are achieved. The working mechanism of the IPE-OLEDs is discussed. The IPE-OLEDs can be easily driven with alternating current signals to independently address each emissive sub-cell. Thus, the OLED illuminant based on IPE-OLEDs enables adjustment of color temperature and intensity. To exhibit the features of the fabricated IPE-OLEDs further, a simple but effective smart lighting system containing IPE-OLEDs and gas detector is constructed, which could be used in the mining industry.
关键词： planar electrodes,OLEDs,color-tunable,alternating current,smart lighting
更新于2025-09-10 09:29:36
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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