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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • FSO Communication System
  • Subcarrier Intensity Modulation
  • Atmospheric Turbulence
  • Bit Error Rate
  • Average Irradiance
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Galgotias College of Engineering and Technology
347 条数据
?? 中文（中国） ▾

  • Nanoscale Interfaces of Janus Monolayers of Transition Metal Dichalcogenides for 2D Photovoltaic and Piezoelectric Applications

    摘要： Using first-principles calculations, we demonstrate a combination of two emergent fields, type-II van der Waal heterostructures and Janus structures, for the purpose of optimizing the harvesting of solar and nanoelectromechanical energy. The most stable stacking order in these nanoscale heterobilayers comprising of Janus monolayers of transition metal dichalcogenides has been ascertained based on the interlayer binding energies. The binding energies in WSeTe/WSTe and MoSeTe/WSTe heterobilayers are found to be -27.93 and -25.67 meV/?2 at an equilibrium interlayer layer distance of 3.25 ? and 3.32 ? respectively, indicating the exothermicity in the process of heterobilayer formation and hence, its experimental feasibility. The mechanical and dynamical stabilities have also been confirmed for these heterobilayers using the Born Huang stability criteria and phonon dispersion calculations. Our results unveil the mechanism underlying the electronic, piezoelectric, photocatalytic properties and carrier mobility in these Janus heterobilayers. Power conversion efficiency in the 2D ultrathin excitonic solar cells constituted by some of the heterobilayers studied in this work, has been found to lie in the range of 15-20%. Moreover, a very high carrier mobility (>200 cm2/V.s) together with a large visible light absorption coefficient (α ~ 105 cm-1) has been observed in these hetero-bilayers. The piezoelectric coefficients in these ultrathin heterobilayers (d33 = 13.91 pm/V) is found to reach close to the values obtained in multilayer/bulk structures built from Janus monolayers of Mo-based dichalcogenides. Our findings highlight the promising applications of these heterobilayers in ultrathin excitonic solar cells, nanoelectronics and nanopiezotronics.

    关键词： van der Waals heterostructures,transition metal dichalcogenides,photovoltaic applications,Janus monolayers,piezoelectricity,carrier mobility

    更新于2025-09-23 15:19:57

  • Tailoring Carrier Dynamics in Perovskite Solar Cells via Precise Di-mension and Architecture Control and Interfacial Positioning of Plasmonic Nanoparticles

    摘要： Placing plasmonic nanoparticles (NPs) in close proximity to semiconductor nanostructures renders effective tuning of the optoelectronic properties of semiconductors through the localized surface plasmon resonance (LSPR)-induced enhancement of light absorption and/or promotion of carrier transport. Herein, we report on, for the first time, the scrutiny of carrier dynamics of perovskite solar cells (PSCs) via sandwiching monodisperse plasmonic/dielectric core/shell NPs with systematically varied dielectric shell thickness yet fixed plasmonic core diameter within electron transport layer (ETL). Specifically, a set of Au NPs with precisely controlled dimensions (i.e., fixed Au core diameter and tunable SiO2 shell thickness) and architectures (plain Au NPs and plasmonic/dielectric Au/SiO2 core/shell NPs) are first crafted by capitalizing on the star-like block copolymer nanoreactor strategy. Subsequently, these monodisperse NPs are sandwiched between the two consecutive TiO2 ETLs. Intriguingly, there exists a critical dielectric SiO2 shell thickness, below which hot electrons from Au core are readily injected to TiO2 (i.e., hot electron transfer (HET)); this promotes local electron mobility in TiO2 ETL, leading to improved charge transport and increased short-circuit current density (Jsc). It is also notable that the HET effect moves up the Fermi level of TiO2, resulting in an enhanced built-in potential and open-circuit voltage (Voc). Taken together, the PSCs constructed by employing a sandwich-like TiO2/Au NPs/TiO2 ETL exhibit both greatly enhanced Jsc and Voc, delivering champion PCEs of 18.81% and 19.42% in planar and mesostructured PSCs, respectively. As such, the judicious positioning of rationally designed monodisperse plasmonic NPs in ETL affords effective tailoring of carrier dynamics, thereby providing a unique platform for developing high-performance PSCs.

    关键词： hot electron transfer,perovskite solar cells,plasmonic nanoparticles,carrier dynamics,localized surface plasmon resonance

    更新于2025-09-23 15:19:57

  • Grain Boundaries Limit the Charge Carrier Transport in Pulsed Laser Deposited ?±-SnWO <sub/>4</sub> Thin Film Photoabsorbers

    摘要： Recently, α-SnWO4 attracted attention as a material to be used as a top absorber in a tandem device for photoelectrochemical water splitting due to its nearly optimum bandgap of ~1.9?eV and an early photocurrent onset potential of ~0 V vs. RHE. However, the mismatch between the charge carrier diffusion length and light penetration depth—which is typical for metal oxide semiconductors—currently hinders the realization of high photoconversion efficiencies. In this work, the pulsed laser deposition process and annealing treatment of α-SnWO4 thin films are elucidated in order to optimize their charge carrier transport properties. A high temperature treatment is found to enhance the photoconductivity of α-SnWO4 by more than one order of magnitude, as measured with time-resolved microwave conductivity (TRMC). A complimentary analysis by time-resolved terahertz spectroscopy (TRTS) shows that this improvement can be assigned to an increase of the grain size in the heat-treated films. In addition, TRTS reveals electron-hole charge carrier mobilities of up to 0.13 cm2 V-1s-1 in α-SnWO4. This is comparable to values found for BiVO4, which is one of the best performing metal oxide photoanode materials to date. These findings show that there is a significant potential for further improving the properties of α-SnWO4 photoanodes.

    关键词： α-SnWO4,metal oxide photoelectrodes,grain boundaries,charge carrier dynamics,pulsed laser deposition

    更新于2025-09-23 15:19:57

  • Exploiting intervalley scattering to harness hot carriers in IIIa??V solar cells

    摘要： Hot carrier solar cells offer the potential to exceed the Shockley–Queisser limit. So far, however, there has been no clear route to achieve this result. Recently, the exploitation of the satellite valleys of the solar absorber material has been proposed as a feasible approach to harness hot carriers. Here, we show that, upon photoinduced and field-aided intervalley scattering to upper L-valleys, hot carriers can be harnessed in InGaAs/AlInAs heterojunctions at voltages defined by the upper valley (~1.25 V in the ideal case) rather than the bandgap of the InGaAs absorber (0.75 eV) under practical operational conditions. The efficiency of the present system does not exceed the single bandgap limit due to a mismatch in the valley degeneracy across the n+-AlInAs/n-InGaAs interface. However, we suggest that this is not a fundamental limitation to the realization of a hot carrier solar cell.

    关键词： InGaAs/AlInAs heterojunctions,hot carrier solar cells,intervalley scattering,valley photovoltaic,Shockley–Queisser limit

    更新于2025-09-23 15:19:57

  • Highly efficient bifacial CsPbIBr <sub/>2</sub> solar cells with a TeO <sub/>2</sub> /Ag transparent electrode and unsymmetrical carrier transport behavior

    摘要： Bright red CsPbIBr2 films possess intrinsic semitransparent features, which make them promising materials for smart photovoltaic windows, power plants, curtain walls, top cells for tandem solar cells, and bifacial photovoltaics. In this work, bifacial CsPbIBr2 perovskite solar cells (PSCs) have been fabricated by adopting an ultrathin silver (Ag) film transparent anode and a tellurium oxide (TeO2) optical modifying layer. The results showed that the transmittance of the TeO2 (40 nm)/Ag (11 nm) transparent top anode matched well with the light absorption range of the CsPbIBr2 film, and the resulting bifacial PSCs exhibited PCEs of 8.04% and 5.32% when illuminated from the FTO and Ag sides, respectively. By introducing cesium iodide-treated CsPbIBr2 layers, the PSCs achieved superior PCEs of 8.46% (FTO side) and 6.40% (Ag side) with a bifacial factor of 75.65%, which is the best performance of bifacial CsPbIBr2 PSCs reported to date. Interestingly, an identical cell showed a significantly higher fill factor, more efficient carrier transport, and better efficiency and stability when illuminated from the Ag side than from the FTO side, a phenomenon strongly related to the parasitic absorption of the spiro-OMeTAD layer below 420 nm. Consequently, we have found a route similar to “shooting fish in a barrel” to enhance the carrier transport, suppress the carrier recombination, and improve the stability of bifacial semitransparent CsPbIBr2 PSCs: turning the Ag side towards the sun.

    关键词： unsymmetrical carrier transport behavior,perovskite solar cells,TeO2/Ag transparent electrode,bifacial CsPbIBr2 solar cells,semitransparent photovoltaics

    更新于2025-09-23 15:19:57

  • An experimental study on the blinking suppression mechanism of organic-inorganic formamidinium lead halide perovskite quantum dots on N-Type semiconductors

    摘要： Lead halide perovskite has emerged as a potential material for a wide range of applications, including solar cells, light-emitting diode displays, lasing, and single photon emitters. To optimize their utilization in optoelectronic devices, the fundamental photophysical properties, especially their charge carrier transition and blinking behaviors, must be elucidated. In this study, we investigate the blinking behaviors of single formamidinium bromide perovskite quantum dots (FAPbBr3 PQDs) on the n-type TiO2 substrate. It is suggested that the electrons from TiO2 fill the trap states of FAPbBr3 PQD during Fermi-level equilibrium, which can reduce the possibility of capturing the hot electrons from PQD into the trap states. In addition, charge separation and charge recombination processes between PQD and TiO2 are expected to shorten the duration of the OFF state, thus stabilizing the fluorescence of PQDs.

    关键词： optoelectronic devices,TiO2 substrate,charge carrier transition,perovskite quantum dots,blinking suppression

    更新于2025-09-23 15:19:57

  • Large signal analysis of multiple quantum well transistor laser: Investigation of imbalanced carrier and photon density distribution

    摘要： In this paper, we present a large-signal and switching analysis for the Heterojunction Bipolar Transistor Laser (HBTL) to reveal its optical and electrical behavior under high current injection conditions. Utilizing appropriate models for carrier transport, nonlinear optical gain, and optical confinement factor, we have simulated the large-signal response of the HBTL in relatively low and high modulation frequencies. Our results predict that for multiple quantum well (MQW) structures at low frequencies, there should not be a difference in either the carrier density or the photon density. However, the carrier concentration can be differently distributed between subsequent wells in the case of a high speed yet large-signal input. This leads to increased linewidth instead as it depends on ΔNqw. We show the effect of different structural parameters on the switching behavior by performing a switching analysis of the single quantum well and MQW structures using computationally efficient numerical methods. A set of coupled rate equations are solved to investigate the large-signal and switching behavior of MQW-HBTL. Finally, to have a comprehensive judgment about this optoelectronic device, we introduce a relative performance factor taking into account all the optoelectronic characteristics such as the output power, ac current gain, modulation bandwidth, and base threshold current, as well as turn-on time in order to design a suitable TL for optoelectronic integrated circuits.

    关键词： multiple quantum well,switching analysis,carrier density,Heterojunction Bipolar Transistor Laser,large-signal analysis,photon density

    更新于2025-09-23 15:19:57

  • [IEEE 2019 2nd International Conference on Power and Embedded Drive Control (ICPEDC) - Chennai, India (2019.8.21-2019.8.23)] 2019 2nd International Conference on Power and Embedded Drive Control (ICPEDC) - Efficient Electron Carrier distribution of n+ MoS <sub/>2</sub> /i-MoS <sub/>2</sub> /p-Si Heterojunction Solar Cell

    摘要： In this paper, modeling and simulation study of energy harvested nano electronics of PV device and its functions under different light intensity have been discussed. The emitter layer of the proposed solar cell has been designed to enhance the photocurrent efficiency even at low electric field. The Electron-hole pair generation of the proposed model is increased to 4.9*1028 [1/ (m2*s)] due to optimized intrinsic MoS2 layer thickness. As a result, the charge carriers distribution enhanced the carrier collection efficiency in the absorber layer. This study reveals that the proposed Energy harvesting device Open-circuit Voltage(Voc) and Short circuit Current density(Jsc) are 1.982[V], 31.22[mA/cm2] respectively and its efficiency found to be 31.91 %. These simulations showed that can be environmental stability and excellent carrier distribution solar cell.

    关键词： electric field,efficiency-region,charge-carrier recombination,Photogeneration,n+MoS2

    更新于2025-09-23 15:19:57

  • Efficient Structure for InP/ZnS-Based Electroluminescence Device by Embedding the Emitters in the Electron-Dominating Interface

    摘要： The charge-carrier distribution has been an important parameter in determining the efficiency of quantum-dot-based light-emitting diodes (QLEDs). In this Letter, we demonstrate a new inverted device structure of ITO/ZnO/polyethylenimine/quantum dots (QDs)/1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBi)/4,4′-bis(9-carbazolyl)-2,2′-biphenyl (CBP)/MoO3/Al for improving the efficiency of InP-QD-based QLEDs. By introducing a thin layer of electron transport materials, the hole accumulation at the hole transport layer and the QD interface is largely reduced, which suppresses the quenching effect of holes on the QD emission. Compared with the conventional device structure with the emitters at ZnO/CBP pn junction, the peak current efficiency (external quantum efficiency) increases from 3.83 (5.17 cd/A) to 6.32% (8.54 cd/A) by imbedding the QDs at the electron-dominating interface of ZnO/TPBi. The analysis reveals that an internal quantum efficiency of nearly 100% is achieved for the InP-QD-based device (with a photoluminescence quantum yield of 32%). This work provides an alternative device structure for achieving high-efficiency QLED devices.

    关键词： electron transport materials,quantum-dot-based light-emitting diodes,internal quantum efficiency,charge-carrier distribution,InP-QD-based QLEDs

    更新于2025-09-23 15:19:57

  • Novel boron doped p-type Cu2O thin film as hole selective contact in c-Si solar cell

    摘要： P-type Cu2O thin film doped with trivalent cation Boron is demonstrated for the first time as an efficient hole selective layer for c-Si heterojunction solar cell. Cu2O and Cu2O:B films were deposited by rf- magnetron sputtering and the optical and electrical properties of the doped and undoped films were investigated. Boron doping enhanced the carrier concentration and the electrical conductivity of the Cu2O film. The band alignment of the Cu2O:B/Si heterojunction was investigated using XPS and UPS measurements. The Cu2O:B/Si interface has a valance band offset of 0.08 eV which facilitates hole transport and a conduction band offset of 1.35 eV which block the electrons. A thin SiOx tunnel oxide interlayer was also explored as the passivation layer. The initial trials of incorporating this Cu2O:B layer as hole transporting layer in a single heterojunction solar cell with the structure, ITO/Cu2O:B/n-Si/Ag, and cell area of 1 cm2 yielded an open-circuit voltage of 370 mV, short-circuit current density of 36.5 mA/cm2 and an efficiency of 5.4 %. This p-type material could find potential applications in various optoelectronic applications like organic solar cells, TFTs, and LEDs.

    关键词： Silicon heterojunction,Photovoltaics,Carrier selective solar cells,Sputtering,Copper Oxide,Hole Selective layer

    更新于2025-09-23 15:19:57