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Strong Cathodoluminescence and Fast Photoresponse from Embedded CH3NH3PbBr3 Nanoparticles Exhibiting High Ambient-Stability
摘要： This study presents a comprehensive analysis of the strong cathodoluminescence (CL), photoluminescence (PL), and photoresponse characteristics of CH3NH3PbBr3 nanoparticles (NPs) embedded in a mesoporous nanowire template. Our study revealed a direct correlation between the CL and PL emissions from the perovskite NPs (Per NPs), for the first time. Per NPs are fabricated by a simple spin coating of perovskite precursor on the surface of metal-assisted-chemically-etched mesoporous Si NWs array. The Per NPs confined in the mesopores show blue shifted and enhanced CL emission as compared to the bare perovskite film, while the PL intensity of Per NPs dramatically high compared to its bulk counterpart. A systematic analysis of the CL/PL spectra reveals that the quantum confinement effect and ultra-low defects in Per NPs are mainly responsible for the enhanced CL and PL emissions. Low-temperature PL and time-resolved PL analysis confirm the high exciton binding energy and radiative recombination in Per NPs. The room temperature PL quantum yield of the Per NPs film on the NW template was found to be 40.5 %, while that of Per film was 2.8%. The Per NPs show improved ambient air-stability than the bare film due to the protection provided by the dense NW array, since dense NW array can slow down the lateral diffusion of oxygen and water molecules in Per NPs. Interestingly, the Si NW/Per NPs junction shows superior visible light photodetection and the prototype photodetector shows a high responsivity (0.223 A/W) with a response speed of 0.32 sec and 0.28 sec of growth and decay in photocurrent, respectively, at 2V applied bias, which is significantly better than the reported photodetectors based on CH3NH3PbBr3 nanostructures. This work demonstrates a low-cost fabrication of CH3NH3PbBr3 NPs on a novel porous NW template, which shows excellent photophysical and optoelectronic properties with superior ambient stability.
关键词： Perovskite Nanoparticles,PL QY enhancement,Porous Si Nanowires,Fast Photoresponse,CL Enhancement
更新于2025-11-21 11:01:37
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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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Controlling porosity and ultraviolet photoresponse of crystallographically oriented ZnO nanostructures grown by pulsed laser deposition
摘要： We have synthesized a series of porous nanostructures of c-axis oriented wurtzite ZnO using glancing angle pulsed laser deposition. During deposition, the oxygen partial pressure (PO2) was varied to study the effects on growth, porosity and optical properties. With varied PO2 the growth of nanostructure changes gradually without losing its crystallographic orientation. The variation in PO2 causes systematic change in porosity of these nanostructures, which strongly influences ultraviolet photoresponse. These results show that the parameters such as surface morphology, growth and porosity as well as the optoelectronic properties can be controlled by variation in PO2 without compromising the crystalline structure.
关键词： Crystalline nanostructures,Photoresponse,Porosity,Ultraviolet,Glancing angle pulsed laser deposition
更新于2025-11-19 16:56:42
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High-performance flexible UV photodetectors based on AZO/ZnO/PVK/PEDOT:PSS heterostructures integrated on human hair
摘要： Flexible optoelectronics is an emerging research field that has attracted profound interest in recent years due to the special functions and potential applications of these devices in flexible image sensors, optical computing, energy conversion devices, Internet of Things and other technologies. Here, we demonstrate the high-performance UV photodetectors using AZO/ZnO nanorods/PVK/PEDOT:PSS heterostructures integrated on human hair. Due to the precise interfacial energy-level alignment among all layers and superior mechanical characteristics of human hair, the as-obtained photodetector shows a fast response time, high photoresponsivity and excellent flexibility. According to integrate 7 heterostructures as 7 display pixels, the flexible UV-image sensor has superior device performance and outstanding flexibility and can produce vivid and accurate images of Arabic numerals from 0 to 9. Different combinations of the two heterostructures can also be used to achieve flexible photon-triggered logic functions including AND, OR and NAND gates. The findings in this work indicate the possibility of using the human hair as fibre-shaped flexible substrate and will allow the use of hair-based hierarchical heterostructures as building blocks to create exciting opportunities for next generation high-performance, multifunctional, low-cost, and flexible optoelectronic devices.
关键词： photon-triggered logic gates,fast photoresponse,UV photodetectors,human hair,optical-image sensors
更新于2025-11-14 17:04:02
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2D Schottky Junction between Graphene Oxide and Transition-Metal Dichalcogenides: Photoresponsive Properties and Electrocatalytic Performance
摘要： 2D graphene is conductor and not a semiconductor. 2D transition—metal dichalcogenides (TMD) is a semiconductor and not a conductor. Preparing 2D composite material that simultaneously possesses both advantages of graphene and TMD has proven to be challenging. In this work, both 2D-WS2/2D-GO and 2D-MoS2/2D-GO composites with few layer thickness are synthesized. The electronic structure indicates a high content of Mo4+ 3d5/2 and W4+4f7/2 with lower binding energy in the 2D composite, which is ascribed to partial loss of surface sulfur atoms in 2D composites and the newly formed heteroatomic bond of CWS and CMoS. The Schottky junction between 2D-GO and 2D-TMD (2D G-T junction) is established and exhibits obvious photoelectric responses. Superior electrocatalytic properties of the two 2D-composites are attributable to the 2D Schottky Junction between 2D-TMDs and 2D-GO. Interlayer electronic coupling in 2D Schottky Junction (2D G-T junction) activates inert sites on the 2D surface of 2D-TMDs or GO. The power conversion efficiency of dye-sensitized solar cells (DSCs) based on 2D-WS2/2D-GO is 9.54% under standard solar illumination intensity (AM1.5, 100 mW cm?2). The value is one of the highest reported efficiencies for DSCs based on Pt-free counter electrodes. Finally, 2D-WS2/2D-GO composites exhibit excellent stability as counter electrode of DSCs.
关键词： photoresponse,interlayer electronic coupling,2D,electrocatalyst,graphene,transition-metal dichalcogenides,Schottky junction
更新于2025-09-23 15:23:52
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Instability of UV Photoresponse in MgZnO Thin Films and Its Improvement by MgO Capping
摘要： Herein, it is shown that the UV photoresponse characteristics of MgZnO thin films deposited by pulsed laser deposition change rapidly with time if the films are exposed to ambient air and that the response can be stabilized significantly by depositing a thin capping layer of MgO on the surface of MgZnO thin film. The decay time of photocurrent in as-deposited MgZnO thin films increases from 1.8 to 229 s and the value of peak responsivity increases by about three orders of magnitude as the film is exposed to air for about 106 s. On application of MgO capping layer, the decay time of the photocurrent marginally increases from (cid:1)0.2 to (cid:1)0.4 s and the value of peak responsivity increases only by one order of magnitude over the span of 106 s, thereafter showing tendency of saturation, implying much better stability in performance. The MgO capping layer is transparent to UV, but acts as a diffusion barrier for oxygen, stabilizing the UV photoresponse.
关键词： UV photoresponse,stability of photoresponse,MgZnO,MgO capping layers
更新于2025-09-23 15:21:01
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Construction of n-TiO2/p-Ag2O Junction on Carbon Fiber Cloth with Visa??NIR Photoresponse as a Filter-Membrane-Shaped Photocatalyst
摘要： The development of effective and reusable photocatalysts with broad-spectra activity has attracted attention. Herein, we have constructed n-TiO2/p-Ag2O junction on carbon fiber (CF) cloth as an efficient and recyclable photocatalyst. With CF cloth as the substrate, TiO2 nanorods (length: 1–2 μm) are prepared by a hydrothermal process, and the in-situ growth of Ag2O nanoparticles (10–20 nm) is then realized by chemical bath deposition route. The flexible CF/TiO2/Ag2O cloth (area: 4 × 4 cm2) shows a broad and strong photo-absorption (200–1000 nm). Under the illumination of visible-light (λ > 400 nm), CF/TiO2/Ag2O cloth can efficiently eliminate 99.2% rhodamine B (RhB), 99.4% acid orange 7 (AO7), 87.6% bisphenol A (BPA), and 89.5% hexavalent chromium (Cr6+) in 100 min, superior to CF/Ag2O cloth (83.5% RhB, 60.0% AO7, 31.2% BPA and 41.8% Cr6+). In particular, under the NIR-light illumination (980 nm laser), CF/TiO2/Ag2O cloth can remove 70.9% AO7 and 60.0% Cr6+ in 100 min, which are significantly higher than those by CF/Ag2O cloth (19.8% AO7 and 18.9% Cr6+). In addition, CF/TiO2/Ag2O cloth (diameter: 10 cm), as a filter-membrane, can effectively wipe off 94.4% flowing RhB solution (rate: ~ 1 L h? 1) at 6th filtering/degrading grade. Thus, CF/TiO2/Ag2O cloth can be used as a Vis–NIR-responded filter-membrane-shaped photocatalyst with high-efficiency for purifying wastewater.
关键词： n-TiO2/p-Ag2O junction,Filter-membrane,Photocatalyst,Vis-NIR photoresponse,Carbon fiber cloth
更新于2025-09-23 15:21:01
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Faceta??Dependent, Fast Response, and Broadband Photodetector Based on Highly Stable Alla??Inorganic CsCu <sub/>2</sub> I <sub/>3</sub> Single Crystal with 1D Electronic Structure
摘要： Low-dimensional metal halides at molecular level, which feature strong quantum confinement effects from intrinsic structure, are emerging as ideal candidates in optoelectronic fields. However, developing stable and nontoxic metal halides still remains a great challenge. Herein, for the first time, high-crystalline and highly stable CsCu2I3 single crystal, which is acquired by a low-cost antisolvent vapor assisted method, is successfully developed to construct high-speed (trise/tdecay = 0.19 ms/14.7 ms) and UV-to-visible broadband (300–700 nm) photodetector, outperforming most reported photodetectors based on individual all-inorganic lead-free metal halides. Intriguingly, facet-dependent photoresponse is observed for CsCu2I3 single crystal, whose morphology consists of {010}, {110}, and {021} crystal planes. The on–off ratio of {010} crystal plane is higher than that of {110} crystal plane, mainly owing to lower dark current. Furthermore, photogenerated electrons are localized in twofold chains created by [CuI4] tetrahedra, leading to relatively small effective mass and fast transport mobility along the 1D transport pathway. Anisotropic carrier transport characteristic is related to stronger confinement and higher electron density for {110} crystal planes. This work not only demonstrates the great potential of CsCu2I3 single crystal in high-performance optoelectronics, but also gives insights into 1D electronic structure associated with fast photoresponse and high anisotropy.
关键词： photodetectors,facet-dependent photoresponse,1D electronic structures,highly stable,fast response
更新于2025-09-23 15:21:01
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Photoresponse of current-biased superconductor/normal metal strip with large ratio of resistivities
摘要： Detection of electromagnetic radiation by superconductor is based on destruction of superconductivity by photons and corresponding change of resistance of superconducting sample. For example in the superconducting bolometer or transition edge sensor (TES) the superconductor is biased near the resistive transition, at temperature below the critical temperature Tc of superconductor [1, 2]. The absorbed photons heat up electrons in the detector, electron temperature increases and it leads to the increase of the temperature dependent resistance of superconductor R(T ). In such a detector the sharper the dependence R(T ) the higher sensitivity the superconducting detector has.
关键词： single photon counting,bolometric regime,photoresponse,superconductor,normal metal
更新于2025-09-23 15:21:01
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Few-layer PdSe2-based field-effect transistor for photodetector applications
摘要： We demonstrate a multilayer palladium diselenide (PdSe2) high-performance photodetector. The photodetector exhibits the photodetectivity of 0.15 ? 1010 Jones under laser illumination (λ ? 655 nm and power of 0.057 mWmm(cid:0) 2). The negative threshold voltage shift in transfer characteristics upon laser illumination is mainly attributed to the photogating effect. Systematic analysis of experimental data indicates that the photogating effect and space charge limited conduction are simultaneously involved in the conduction mechanism. We observe that the photogenerated current increases logarithmically as the light intensity increases, and it persists (~200 s) even after stopping the illumination. The slow decrease in current was attributed to the trapping of photogenerated charge carriers at the PdSe2/SiO2 interface and the defects in the structure of PdSe2. We also observe a reproducible and stable time-resolved photoresponse with respect to the incident laser power. We believe that this study can be an important source of information and can help researchers to continue to investigate methods that would allow them to maximise the potential of PdSe2 for photodetector applications.
关键词： Palladium diselenide,Photodetector,Field effect transistor,Two-dimensional materials,Photoresponse
更新于2025-09-23 15:21:01