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Plasmonic hole-transport-layer enabled self-powered hybrid perovskite photodetector using a modified perovskite deposition method in ambient air
摘要： Herein, we report on an air-processed high performance self-powered hybrid perovskite (Pe) photodetector with plasmonic Silver nanoparticle (Ag NP) embedded hole-transport-layer (HTL), without the use of any electron-transporting layer (ETL). It is demonstrated that in the absence of ETL in the device, the Ag NPs embedded PEDOT:PSS HTL improves the photodetection performance significantly. We used a novel N2 gas assisted fast crystallization method for the deposition of perovskite film in ambient condition to form uniform Pe layer as compared to the nonuniform film obtained in conventional deposition method. The Pe film on Ag NPs embedded PEDOT:PSS layer shows enhanced optical absorption in the UV-visible region due to the plasmonic absorption by the Ag NPs. At zero bias, the ETL-free Ag NPs-Pe hybrid device shows ~45% enhanced responsivity and ~3 times faster photoresponse compared to the pristine device. The enhancements in the performance of hybrid photodetector are attributed to plasmon-enhanced optical absorption and hot electron generation, as well as improvement in charge extraction and transport by Ag NPs, which are corroborated by steady-state and time-resolved photoluminescence measurements. Impedance analysis of the devices shows the reduced carrier transfer resistance of the hybrid device, which results in superior transport of photo-generated charge carriers. Direct evidence for the increase in the work function by ~ 47 meV for Ag NPs doped PEDOT:PSS film is provided from the Kelvin probe force microscopy analysis. This increase in work function enables favorable band alignment with reduced energy barrier and a superior carrier transport resulting in improved photodetection performance for the hybrid device. Our results are significant for the development of high-performance, low-cost, ETL free plasmonic perovskite photodetectors for futuristic applications.
关键词： Plasmonic perovskite photodetector,Kelvin probe force microscopy,Fast photoresponse,Self-biased photodetector
更新于2025-11-21 11:01:37
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A novel Ag nanoparticles/TiO2 nanowires-based photodetector and glucose concentration detection
摘要： A unique vapour transport cum glancing angle deposition (VT-GLAD) technique was employed to fabricate titanium dioxide (TiO2) nanowires (NWs). The NWs were grown and assembled to form the clusters. Both brookite (412) and rutile (002) phase for TiO2 was obtained from X-ray diffraction (XRD). The d spacing of ~ 1.37 ? was calculated from the transmission electron microscopy (TEM) of TiO2 NWs, which corresponds to (002) crystal plane. The silver (Ag) nanoparticles (NPs) on TiO2 NWs were grown using thermal evaporation cum GLAD technique. The presence of Ag NPs on the TiO2 NWs enhanced the photoconduction as compared to bare TiO2 NWs device. The maximum photosensitivity of the Ag NPs/TiO2 NWs based device was recorded ~ 1.6 times compared to the bare TiO2 NWs based device at ? 2.5 V. The Ag NPs containing device was highly UV sensitive and maximum responsivity for the device was calculated to be ~ 2.3 A/W at 370 nm. The device also possessed high responsivity rejection (RR) ratio of ~ 6.5 between UV (370 nm) and visible (450 nm) light. The Ag NPs decorated TiO2 NWs based detector also showed response to white light. The different concentration of glucose into deionised (DI) water-based solution was detected precisely under white light illumination. The normalised (light/dark) detector current/glucose concentration value was decreased from ~ 0.19 to ~ 0.05 at ? 2.5 V, with an increase in glucose concentration into the solution from 40 mg/dl to 200 mg/dl.
关键词： photodetector,Ag nanoparticles,TiO2 nanowires,VT-GLAD technique,glucose concentration detection
更新于2025-11-21 11:01:37
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Architectural Design of Photodetector Based on 2D (MoS <sub/>2</sub> ?Nanosheets)/1D (WS <sub/>2</sub> ?Nanorods) Heterostructure Synthesized by Facile Hydrothermal Method
摘要： Hydrothermal technique is utilized to synthesize 2D/1D heterostructure based on MoS2 (nanosheets)/WS2 (nanorods) for photodetector application. The sensor was fabricated by drop cast technique. X-Ray Diffraction (XRD), Fourier Transform Infra-red (FTIR) Spectroscopy, Field-Emission Scanning Electron Microscopy (FESEM), UV-Visible (Uv-Vis), Raman and X-Ray Photoelectron spectroscopy (XPS) were performed to characterize the synthesized sample. The optical sensor based on heterostructure was studied as a function of laser wavelength (λex): 635 nm (red), 785 nm (infra-red) and 1064 nm (near infra-red) and power of illuminated laser sources. The device exhibits photoresponsivity in a broadband range from the visible to the near-infrared (600–1065 nm, yield a photoresponsivity (Rp) = 15 μA/W and high speci?c detectivity (D?) = 24 × 106 jones at λex = 785 nm). The photoresponsive characteristics of MoS2/WS2 heterostructure hold the principle of simple power law.
关键词： MoS2 nanosheets,photodetector,hydrothermal method,WS2 nanorods,2D/1D heterostructure
更新于2025-11-21 11:01:37
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Ferroelectric Enhanced Performance of a GeSn/Ge Dual-Nanowire Photodetector
摘要： GeSn offers a reduced bandgap than Ge and has been utilized in Si-based infrared photodetectors with extended cutoff wavelength. However, traditional GeSn/Ge heterostructure usually consists defects like misfit dislocations due to the lattice mismatch issue. The defects with the large feature size of photodetector fabricated on bulk GeSn/Ge heterostructure induces considerable dark current. Here, we demonstrate a flexible GeSn/Ge dual-nanowire (NW) structure, in which the strain relaxation is achieved by the elastic deformation without introducing defects and the feature dimension is naturally at nanoscale. Photodetector with low dark current can be built on GeSn/Ge dual-NW, which exhibits an extended detection wavelength beyond 2 μm and the enhanced responsivity compared to Ge NW. Moreover, the dark current can be further suppressed by the depletion effect from ferroelectric polymer side gate. Our work suggests the flexible GeSn/Ge dual-NW may open an avenue for Si-compatible optoelectronic circuits operating in the short-wavelength infrared range.
关键词： Nanowire,Germanium-tin,Molecular beam epitaxy (MBE),Side-gated,Photodetector,Ferroelectrical polymer
更新于2025-11-21 11:01:37
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Two-dimensional beta-lead oxide quantum dots
摘要： In recent years, black-phosphorus-analogue (BPA) two-dimensional (2D) materials have been explored to demonstrate promising optoelectronic performances and distinguished ambient stabilities, holding great promise in practical applications. Here, one new kind of BPA material, orthorhombic β-PbO quantum dots (QDs), is successfully fabricated by a facile liquid phase exfoliation (LPE) technique. The as-prepared β-PbO QDs show a homogeneous distribution of the lateral size (3.2 ± 0.9 nm) and thickness (2.5 ± 0.5 nm), corresponding to 4 ± 1 layers. The carrier dynamics of β-PbO QDs was systematically investigated via a femtosecond resolution transient absorption approach in the visible wavelength regime and it was clarified that two decay components were resolved with a decay time of τ1 = 2.3 ± 0.3 ps and τ2 = 87.9 ± 6.0 ps, respectively, providing important insights into their potential applications in the field of ultrafast optics, nanomechanics and optoelectronics. As a proof-of-concept, β-PbO QDs were, for the first time to our knowledge, fabricated as a working electrode in a photoelectrochemical (PEC)-typed photodetector that exhibits significantly high photocurrent density and excellent stability under ambient conditions.
关键词： photoelectrochemical photodetector,β-PbO quantum dots,carrier dynamics,liquid phase exfoliation
更新于2025-11-19 16:56:42
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ZIF-8@H:ZnO Core-shell nanorods arrays/Si heterojunction self-powered photodetector with ultrahigh performance
摘要： The native defects will degrade the performance and stability of the optoelectric device. Herein, a zeolitic imidazolate framework-8 (ZIF-8)@H:ZnO core-shell nanorods arrays/Si heterojunction self-powered photodetector is demonstrated. Combining hydrogenation and ZIF-8 passivation, its photoresponsive characteristics are greatly enhanced. The photodetector exhibits superior detectivity of ~2.14×1016 Jones (1 Jones=1 cm Hz1/2 W-1), high responsivity of ~7.07×104 mA W-1, prominent sensitivity of ~2.08×1012 cm2 W-1 and broadband photodetection ranging from the ultraviolet to the near infrared. As critical figures of merit, its responsivity increases by nearly 5 orders of magnitude than that of pristine ZnO nanorods arrays/Si heterojunction photodetector. More importantly, the comprehensive performance of ZIF-8@H:ZnO core-shell nanorods arrays/Si heterojunction photodetector not only achieves a record high value for ZnO-based photodetectors reported so far, but also can be comparable with that of two-dimensional (2D) materials, zero-dimensional (0D) materials, topological insulators, perovskites and other oxides based self-powered photodetectors. The novel post-treatment strategy has great potential in developing high-performing self-powered photodetectors. Meanwhile, this work may be extended to other oxides based optoelectronic devices.
关键词： core-shell nanorods,heterojunction,passivation,self-powered photodetector,ZnO,ZIF-8,hydrogenation
更新于2025-11-14 17:04:02
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Colloidal-Quantum-Dot-in-Perovskite Nanowires
摘要： Colloidal quantum dots are materials of interest in infrared detection – a consequence of their near-infrared light harvesting capability, tunable bandgap, and solution-processing. Herein we develop a quantum-dot-in-perovskite-nanowire consisting of PbS quantum dots embedded inside MAPbI3 nanowires. The kinetics of perovskite nanowire growth were tracked. We found that N, N-dimethylformamide induced the formation of perovskite nanowires, and that their growth was accelerated upon PbS quantum dot inclusion. We then used this nanocomposite to fabricate photodetectors that showed a light response from the visible to near infrared region up to 940 nm. Finally, a flexible photodetector was fabricated on a polyethylene terephthalate substrate.
关键词： MAPbI3 nanowires,flexible photodetector,PbS quantum dots
更新于2025-11-14 17:04:02
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Increasing photoluminescence quantum yield by nanophotonic design of quantum-confined halide perovskite nanowire arrays
摘要： High photoluminescence quantum yield (PLQY) is required to reach optimal performance in solar cells, lasers and light-emitting diodes (LEDs). Typically, PLQY can be increased by improving the material quality to reduce the non-radiative recombination rate. It is in principle equally effective to improve the optical design by nanostructuring a material to increase light out-coupling efficiency and introduce quantum confinement, both of which can increase the radiative recombination rate. However, increased surface recombination typically minimizes nanostructure gains in PLQY. Here a template guided vapor phase growth of CH3NH3PbI3 (MAPbI3) nanowire (NW) arrays with unprecedented control of NW diameter from the bulk (250 nm) to the quantum confined regime (5.7 nm) is demonstrated, while simultaneously providing a low surface recombination velocity of 18 cm s-1. This enables a 56-fold increase in the internal PLQY, from 0.81 % to 45.1 %, and a 2.3-fold increase in light out-coupling efficiency to increase the external PLQY by a factor of 130, from 0.33 % up to 42.6 %, exclusively using nanophotonic design.
关键词： light out-coupling,photoluminescence quantum yield,quantum confinement,perovskite,photodetector
更新于2025-11-14 15:28:36
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Modulated charge transport characteristics in solution-processed UV photodetector by incorporating localized built-in electric field
摘要： The application of ZnO in the field of ultraviolet (UV) photodetectors is hindered by the lower responsivity, which is attributed to the strong band-to-band direct recombination caused by its large exciton binding energy and defect-assisted charge recombination related with the presence of defect states. Here, a solution-processed ZnO:Poly[N-90-heptadecanyl-2,7- carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)] (PCDTBT) composite photosensitive layer is employed to overcome these shortcomings. By incorporating PCDTBT, the localized built-in electric field can be constructed, which effectively facilitates the photogenerated exciton dissociation in annealing-free ZnO layer. Meanwhile, the formed depletion region in dark reduces the majority carrier density, thus decreasing the dark current of the photodetector. Furthermore, the absorption spectrum of PCDTBT perfectly overlaps the photoluminescence of ZnO, which is beneficial for the reutilization of carrier recombination energy by fluorescence resonance energy transfer. This study reveals that the charge recombination loss in ZnO limits the photoresponse, and points a direction to improve the light detection capacity of UV photodetectors.
关键词： ZnO,UV photodetector,Solution-processed,PCDTBT,Built-in electric field
更新于2025-11-14 15:27:09
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[IEEE 2019 International Conference on Advances in Computing and Communication Engineering (ICACCE) - Sathyamangalam, Tamil Nadu, India (2019.4.4-2019.4.6)] 2019 International Conference on Advances in Computing and Communication Engineering (ICACCE) - Estimation of maximum range for underwater optical communication using PIN and avalanche photodetectors
摘要： This paper presents an estimate of underwater optical communication (UWOC) range, using PIN and avalanche photodetectors (APDs). In this simulation-based study, the maximum range while transmitting high-quality video at 6Mbps speed is estimated as 520m in Pure Sea water, 65m in Clear Ocean and 44m in Coastal waters, when using a 100mW laser and APD. The channel here is modeled to include the effect of attenuation and noise. This work quantifies the benefits of using an adaptive system where the wavelength (blue, blue-green and green) of transmission and modulation scheme is changed based on water transmission. Wavelength adaptation according to varying water transmission was found to provide 16 to 40dB advantage in SNR, compared to a system with fixed wavelength, in different waters. A recommendation for wavelength adaptable transmitter design is made based on this. This study assumes the current state of the art in commercially available components.
关键词： Laser,photodetector,underwater communication,range,attenuation
更新于2025-11-14 15:24:45