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Ultralong CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> nanowires synthesized by a ligand-assisted reprecipitation strategy for high-performance photodetectors
摘要： Organic-inorganic hybrid perovskite nanowires with well-defined structures have attracted considerable attention for optoelectronic applications. Perovskite nanowires integrated into practical optoelectronic devices are often hindered by the poor crystalline quality. Herein, a ligand-assisted reprecipitation strategy (LARP) is employed to prepare ultralong and freestanding CH3NH3PbI3 nanowires in large-scale. Oleylamine is adopted as an inhibitor, which can create a passivation layer on the surface of CH3NH3PbI3, to slow down the crystallization rate of CH3NH3PbI3 nanowire. With the low crystallization rate, several millimeters long and high-quality CH3NH3PbI3 nanowires with smooth surfaces can be synthesized in a large scale. Photodetectors fabricated on oleylamine assistant synthesized CH3NH3PbI3 nanowires exhibit high detectivity, which is five times higher than that of none oleylamine assistant synthesized CH3NH3PbI3 nanowires photoanode.
关键词： Organic-inorganic hybrid perovskite,photodetectors,nanowires,ligand-assisted reprecipitation strategy,optoelectronic applications,oleylamine
更新于2025-09-19 17:13:59
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Evidence for Ferroelectricity of All-Inorganic Perovskite CsPbBr3 Quantum Dots
摘要： The ferroelectric-optical combination of properties in halide perovskites has attracted tremendous interests because of its potential for optoelectronic and energy applications. However, very few reports focus on the ferroelectricity of all-inorganic halide perovskites quantum dots. Herein, we report a excellent ferroelectricity in CsPbBr3 quantum dots (QDs) with a saturation polarization of 0.25 μC/cm2. Differential scanning calorimeter (DSC), X-ray diffraction (XRD), transmission electronic microscopy (TEM) revealed that the mechanism of ferroelectric-paraelectric switching of CsPbBr3 QDs can be attributed to the phase transition from cubic phase (????3??) to orthorhombic phase (Pna21). In the orthorhombic CsPbBr3, the distortion of octahedral [PbBr6]4- structural units and the off-center Cs+ generated the slightly separated centres of positive charge and negative charge, resulting in the ferroelectric properties. The variable temperature emission spectrum from 328 K to 78 K exhibits green luminescence and the gradually red shift due to the phase transition. This finding opens up a avenue to explore the ferroelectric-optical properties of inorganolead halide perovskites for high-performance multifunctional materials.
关键词： CsPbBr3 quantum dots,all-inorganic perovskite,phase transition,optoelectronic applications,ferroelectricity
更新于2025-09-16 10:30:52
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All-Optical Switching Based on the Plasma Channel Induced by Laser Pulses
摘要： We display a theoretical and experimental study of all-optical switching for signal lasers based on the plasma channel induced by the control laser. Using the plasma channel generated in the carbon disulfide (CS2) solution, the signal light can be modulated as some spatial distributions including unchanging, ring-shaped beam, and other intensity profiles. The modulation on the signal light can be conveniently adjusted by changing the control light’s incident intensity distribution. We can infer the dark spot shape in the modulated signal laser through the intensity profile of control laser beam. These results provide the great potential of plasma channel induced by lasers as an all-optical switching for various optoelectronic applications.
关键词： all-optical switching,plasma channel,spatial modulation,optoelectronic applications,laser pulses
更新于2025-09-12 10:27:22
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New organic molecular based on Bis-Dipolar Diphenylamino-EndcappedOligo Aryl Fluorene Application for organic solar cells
摘要： In this work, we report on the structural, optical and electronic properties of a series of D-π-A-π-D type bis-dipolar Diphenylamino-Endcappedoligoarylfluorenes, (OF(2)Ar-NPh(2)). These molecules are studied by means of quantum chemical calculations based on density functional theory (DFT) using B3LYP functional with 6-31G(d,p) for all atoms and all states (ground and excited ). The study of the geometrical parameters, ground state (p, n) showed that the structures of these molecules are planar. As a result, the electronic properties HOMOs, LUMOs, energy gaps, were determined from the fully optimized structures. The absorption of these molecules were calculated using (TD-DFT)-B3LYP/631G (d,p) method. This fundamental information is a valuable data in designing and making promising materials for optoelectronic applications.
关键词： Optoelectronic applications,DFT,Organic,Photovoltaic cells
更新于2025-09-12 10:27:22
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Controlled Plasma Thinning of Bulk MoS <sub/>2</sub> Flakes for Photodetector Fabrication
摘要： The electronic properties of layered materials are directly determined based on their thicknesses. Remarkable progress has been carried out on synthesis of wafer-scale atomically molybdenum disulfide (MoS2) layers as a two-dimensional material in the past few years in order to transform them into commercial products. Although chemical/mechanical exfoliation techniques are used to obtain a high-quality monolayer of MoS2, the lack of suitable control in the thickness and the lateral size of the flakes restrict their benefits. As a result, a straightforward, effective, and reliable approach is widely demanded to achieve a flake with control in its thickness for optoelectronic applications. In this study, thick MoS2 flakes are obtained by a short-time bath sonication in dimethylformamide solvent, which are thinned with the aid of a sequential plasma etching process using H2, O2, and SF6 plasma. A comprehensive study has been carried out on MoS2 flakes based on scanning electron microscopy, atomic force microscopy, Raman, transmission electron microscopy, and X-ray photoelectron microscopy measurements, which ultimately leads to a two-cycle plasma thinning method. In this approach, H2 is used in the passivation step in the first subcycle, and O2/SF6 plasma acts as an etching step for removing the MoS2 layers in the second subcycle. Finally, we show that this technique can be enthusiastically used to fabricate MoS2-based photodetectors with a considerable photoresponsivity of 1.39 A/W and a response time of 0.45 s under laser excitation of 532 nm.
关键词： photodetector,MoS2,optoelectronic applications,plasma thinning,two-dimensional materials
更新于2025-09-12 10:27:22
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Micro‐ and Nanolasers
摘要： A laser is a device that emits strong coherent light through a process of light amplification by stimulated emission of radiation. The theoretical foundation for the laser was established by Albert Einstein theorizing on the existence of stimulated emission in 1916. The first laser was built by Theodore Maiman in 1960 based on the theoretical work of Charles Townes and Arthur Schawlow. The invention and continuous development of the laser has revolutionized science, technology, and industry. Miniaturization of lasers has been promoting the development and application of laser technology. For example, compact semiconductor lasers have become an integral part of our everyday life. With the development of micro- and nanofabrication technology, including both top-down and bottom-up techniques, the dimensions of lasers have been shrunk down to micro- and nanoscale. With an unprecedented ability to deliver intense coherent light at (sub)wavelength scale, such micro- and nanolasers are promising to trigger the next revolution in the laser and related fields. Indeed, the micro- and nanolasers are or will be unlocking their potential in photonic and optoelectronic applications, such as chemical and biological sensing, laser display and holography, on-chip optical communication and processing, and so on.
关键词： micro- and nanolasers,on-chip optical communication and processing,chemical and biological sensing,photonic and optoelectronic applications,laser display and holography
更新于2025-09-11 14:15:04
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Rational Molecular Design towards NIR Absorption; Efficient Diketopyrrolopyrrole Derivatives for Organic Solar Cells and Photothermal Therapy
摘要： After the development of diketopyrrolopyrrole (DPP) in 1974, its derivatives have been widely explored for optoelectronic applications. In this review we discuss various donor/acceptor functionalized DPPs which are recently published and systematically compared their properties. The modification of donor functionalized DPP to tetracyanobutadiene (TCBD) bridged derivatives with improved acceptor strength, absorption towards near infra-red region have shown some exciting advancement in non-fullerene acceptors for organic solar cells and as therapeutic agents in photothermal therapy are also described. The optoelectronic properties in relation to structural changes such as change of end capping groups, donor–acceptor moieties, aromatic moiety in DPP core and number of DPP units in the molecular structure are discussed. We are expecting that the current review will provide guidelines for the exploration of new DPP based efficient materials for photovoltaic and biomedical applications.
关键词： diketopyrrolopyrrole,optoelectronic applications,photothermal therapy,organic solar cells,NIR absorption
更新于2025-09-11 14:15:04
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European Microscopy Congress 2016: Proceedings || Is the electronic structure of few layer transition metal dichalcogenides always two dimensional ?
摘要： The electronic structure of the transition metal dichalcogenides (TMDs) is investigated using angle-resolved photoemission spectroscopy (ARPES). We observe a new class of layered materials that can be prepared in various thicknesses down to single layers. Compared with the more well-known graphene, the TMDs are semiconductors and can be more useful in applications where an energy gap is essential. Our results show that the electronic structure of the TMDs is highly dependent on the number of layers, with a transition from indirect to direct bandgap as the thickness is reduced to a single layer. This transition is accompanied by a significant enhancement in photoluminescence intensity, making monolayer TMDs promising candidates for optoelectronic applications.
关键词： Angle-resolved photoemission spectroscopy,Bandgap engineering,Electronic structure,Optoelectronic applications,Transition metal dichalcogenides
更新于2025-09-10 09:29:36
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Highly Promoted Carrier Mobility and Intrinsic Stability by Rolling Up Monolayer Black Phosphorus into Nanoscrolls
摘要： Rolling up two-dimensional (2D) materials into nanoscrolls could not only retain the excellent properties of their 2D hosts, but also display intriguing physical and chemical properties that arise from their 1D tubular structures. Here, we report a new class of black phosphorus nanoscrolls (bPNSs), which are stable at room-temperature and energetically more favorable than 2D bP. Most strikingly, these bPNSs hold tunable direct band gaps and extremely high mobilities (e.g., the mobility of the double-layer bPNS is about 20-fold higher than that of 2D bP monolayer). Their unique self-encapsulation structure and layer-dependent conduction band minimum can largely prevent the entering of O2 and the production of O?2 and thereby suppress the possible environmental degradation as well. The enhanced intrinsic stability and promoted electronic properties render bPNSs great promise in many advanced electronics or optoelectronics applications.
关键词： optoelectronic applications,black phosphorus nanoscrolls,carrier mobility,intrinsic stability,electronic properties
更新于2025-09-09 09:28:46
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Direct Growth of Graphene on Fused Quartz by Atmospheric Pressure Chemical Vapor Deposition With Acetylene
摘要： Direct growth of graphene on target substrates is significant for many optoelectronic applications. A direct growth method of graphene on fused quartz by atmospheric pressure chemical vapor deposition with acetylene as carbon source has been proposed. The functions of growth parameters have been studied by Raman spectroscopy, scanning electron microscope and transmission electron microscope. Large area high quality bilayer AB-stacked graphene films can be fabricated continuously on the whole fused quartz surface with optimal parameters. Governed by a surface-assisted catalyzed growth mode, the short of growth time is not enough to cover the surface completely, while longer duration will induce excrescent layers. Meanwhile, the hydrogen kinetics shows a competition between the catalytic effect and etching effect of hydrogen. The former is dominant with the ratio of hydrogen and argon flow rate below 0.33, while the later take over with more hydrogen concentration. To corroborate the application, a centimeter level graphene optical modulator is assembled with the as-grown samples and proved to work well with a maximum modulation depth of ~3.4% at 1000 nm wavelength. This work paves a convenient way for graphene growth directly on fused quartz with acetylene for great potential applications in photoelectric fields.
关键词： Optoelectronic applications,Fused quartz,Graphene,Atmospheric pressure chemical vapor deposition,Acetylene
更新于2025-09-09 09:28:46