- 标题
- 摘要
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- 实验方案
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Performance Improvement of Gate-Tunable Organic Light-Emitting Diodes with Electron-Transport and Hole-Blocking Layers
摘要： The current density and luminance of gate-tunable organic light-emitting diodes (OLEDs) can be modulated by application of an external gate potential. However, existing gate-tunable OLEDs require further optimization to make them suitable for practical use. In this work, the rapid electron conduction of 4,4’-bis(N-carbazolyl)-1,1’biphenyl (CBP) molecules under low operating potential is demonstrated in polymer electrolyte-coated super yellow (SY) polymer light-emitting diodes (PLEDs). This behavior is attributed to the facile electrochemical n-doping of CBP by the polymer electrolyte infiltrated into the SY PLED through the porous aluminum cathode. The field-modulated conductivity of CBP upon applying an external gate potential to electrolyte-gated (EG) PLEDs is demonstrated. These phenomena lead to the improved performance of EG SY PLEDs with a CBP electron-transport layer and 1,3,5-tris[(3-pyridyl)-phen-3-yl]benzene) (TmpypB) hole-blocking layer between the porous aluminum cathode and SY emissive layer, including low turn-on voltage (1.5 V), low current density leakage (0.01 mA/cm2), low off luminance (<0.01 cd/m2), saturated on-current density (2 mA/cm2) and on-luminance (100 cd/m2), and largely suppressed hysteresis. These results pave the path for practical application of EG OLEDs in displays, especially near-to-eye displays.
关键词： facile electrochemical doping,saturated on-current density and on-luminance,low off-current density leakage and off-luminance,suppressed hysteresis,near-to-eye displays,gate-tunable organic light-emitting diodes,grayscale displaying,porous electrodes
更新于2025-09-23 15:21:01
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Gate Tunable Symmetric Bipolar Junction Transistor Fabricated via Femtosecond Laser Processing
摘要： Two-dimensional (2D) bipolar junction transistor (BJT) with van der Waals heterostructures plays an important role in the development of future nanoelectronics. Herein, a convenient method is introduced for fabricating a symmetric bipolar junction transistor (SBJT) constructed with black phosphorus and MoS2 with femtosecond laser processing. This SBJT exhibits good bidirectional current amplification thanks to its symmetric structure. Next, we place a top gate on one side of the SBJT to change the difference in the major carrier concentration between the emitter and collector in order to further investigate the effect of electrostatic doping on the device’s performance. The SBJT can also act as a gate tunable phototransistor with good photodetectivity and photocurrent gain of β ~ 21. Scanning photocurrent images are used to determine the mechanism governing photocurrent amplification in the phototransistor. These results promote the development of the applications of multifunctional nanoelectronics based on 2D materials.
关键词： Femtosecond laser processing,Phototransistor,Two-dimensional materials,Bipolar junction transistor,Gate tunable
更新于2025-09-23 15:19:57
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Graphene Plasmonic Fractal Metamaterials for Broadband Photodetectors
摘要： Metamaterials have recently established a new paradigm for enhanced light absorption in state-of-the-art photodetectors. Here, we demonstrate broadband, highly efficient, polarization-insensitive, and gate-tunable photodetection at room temperature in a novel metadevice based on gold/graphene Sierpinski carpet plasmonic fractals. We observed an unprecedented internal quantum efficiency up to 100% from the near-infrared to the visible range with an upper bound of optical detectivity of 1011 Jones and a gain up to 106, which is a fingerprint of multiple hot carriers photogenerated in graphene. Also, we show a 100-fold enhanced photodetection due to highly focused (up to a record factor of |e/e0| ≈ 20 for graphene) electromagnetic fields induced by electrically tunable multimodal plasmons, spatially localized in self-similar fashion on the metasurface. Our findings give direct insight into the physical processes governing graphene plasmonic fractal metamaterials. the proposed structure represents a promising route for the realization of a broadband, compact, and active platform for future optoelectronic devices including multiband bio/chemical and light sensors.
关键词： graphene,metamaterials,plasmonic fractals,gate-tunable,photodetectors,polarization-insensitive,broadband
更新于2025-09-23 15:19:57
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Graphene/HgTe Quantum-Dot Photodetectors with Gate-Tunable Infrared Response
摘要： Graphene-based vertical heterostructures are of interest as emerging electronic and optoelectronic devices. Here, we report the study of photovoltaic response from graphene/HgTe quantum-dot junction. The graphene/HgTe quantum-dot junction combines the high carrier mobility of graphene and tunable infrared optical absorption of HgTe colloidal quantum dots, which offers promising route for the next-generation infrared optoelectronics. We demonstrate that both the sign and magnitude of the short-circuit photocurrents and open-circuit voltages can be controlled by the applied gate voltage, which tunes the Fermi level and the interfacial built-in potential across the junction. The interfacial energy band diagram is deduced to provide the fundamental understanding of the essential physics behind the graphene/quantum-dot film junction.
关键词： graphene/HgTe CQDs junction,photovoltaic detection,interfacial photocarrier transport,gate-tunable photoresponse,infrared
更新于2025-09-19 17:13:59
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Ideal <i>pn</i> Diodes from Single-Walled Carbon Nanotubes for Use in Solar Cells: Beating the Detailed Balance Limit of Efficiency
摘要： Though many technologies exist for improving solar cell efficiencies, there remains an unexplored fundamental parameter, the diode ideality factor (??), that we can exploit. The Shockley-Queisser limit states that the maximum solar conversion efficiency in a single pn junction is achievable only when it is operated in the ideal diode limit of ?? = 1. Generation and recombination losses correlate directly to an increase in the dark saturation current and ??, both of which have competing effects on the open-circuit voltage. Here, we demonstrate a new approach to improving the efficiency of solar cells beyond the detailed balance limit by gate modulation of the diode’s ideality factor in ideal carbon nanotube pn diodes. We show that the open-circuit voltage can be tuned in direct proportion to ?? without impacting the reverse bias leakage current or the short circuit current. We show that our approach is similar to the enhancement from solar concentrators without actually using them. We achieve an open-circuit voltage that is ~300% higher than that given by the detailed balance limit.
关键词： pn junction,photovoltaic effect,open-circuit voltage,gate-tunable diodes,Single-walled carbon nanotube,detailed balance limit
更新于2025-09-16 10:30:52
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Integration of MoS <sub/>2</sub> with InAlAs/InGaAs Heterojunction for Dual Color Detection in Both Visible and Near‐Infrared Bands
摘要： At present, dual-channel or even multi-channel recording is a developing trend in the field of photodetection, which is widely applied in environment protection, security, and space science and technology. This paper proposes a novel MoS2/InAlAs/InGaAs n–i–n heterojunction phototransistor by integrating multi-layered MoS2 with InGaAs-based high electron mobility transistors (InGaAs-HEMTs). Due to the internal photocurrent amplification in the InGaAs channels with a narrow energy bandgap of 0.79 eV, this device exhibits high photoresponsivity (R) of over 8 × 105 A W–1 under near-infrared illumination of 1550 nm at 500 pW. Furthermore, with the combination of the photoconductance effect in the vertical MoS2/InAlAs/InGaAs n–i–n heterojunction and the photogating effect in the lateral phototransistor, this device possesses a unique characteristic under visible illumination that its photoresponsivity can be tuned by the top gate electrode from 6 × 105 A W–1 to -4 × 105 A W–1 by gate voltage. This may lead to a new application as an optically controlled electronic inverter, which needs further study in depth. This MoS2/InAlAs/InGaAs phototransistor builds up a new bridge between 2D materials and conventional ternary compounded semiconductor devices.
关键词： MoS2/InAlAs/InGaAs van der Waals heterojunction,gate-tunable negative/positive responsivity,dual-band photodetection,2D electron gas
更新于2025-09-11 14:15:04