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Highly Efficient and Stable CsPbBr3 Perovskite Quantum Dots by Encapsulating in Dual-Shell Hollow Silica Spheres for WLEDs
摘要： Poor stability of CsPbX3 (X = Cl, Br or I) perovskite quantum dots (QDs) has greatly hindered their practical photoelectric applications, and how to improve it still remains a critical challenge. Herein, we encapsulated the CsPbBr3 QDs into a dual-shell hollow silica (SiO2) spheres via a simple successive ionic layer adsorption and reaction (SILAR) method. The hierarchical dual-shell structures permit CsPbBr3 QDs to be anchored on the interior of the SiO2 spheres while keeping the outside surface undisturbed, which can protect CsPbBr3 QDs from direct exposure to the atmosphere. Due to the comprehensive protection of dual-shell hollow SiO2 spheres, the CsPbBr3/SiO2 nanospheres exhibit markedly enhanced stability against light and heat, with residual PL intensity of 89% after continuous exposure of 72 h to UV light and 65% at 100?C heat treatment, respectively. In addition, an optimal PLQY of 89% is obtained with suppressed nonradiative recombination. Finally, the fabricated white light-emitting diodes (LEDs) device by employing CsPbBr3/SiO2 green phosphors could achieve a wide color gamut covering up to 136% of the NTSC standard. This work provides a novel SiO2-based encapsulation approach to solve the intrinsic instability issues of CsPbBr3 QDs, which has a profound impact on their practical applications.
关键词： photoluminescence quantum yield,CsPbBr3 quantum dots,dual-shell hollow silica spheres,stability,white light-emitting diodes
更新于2025-09-23 15:21:01
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CsPbBr3 nanowire polarized light-emitting diodes through mechanical rubbing
摘要： Anisotropic films composed of aligned CsPbBr3 nanowires (NWs) have been successfully fabricated using a mechanical rubbing method. The films with dense and uniform morphology show polarization photoluminescence (PL) behavior. Combining with an optimal device structure, a polarized light-emitting diode (LED) with a turn-on voltage as low as 6.5 V was achieved.
关键词： CsPbBr3 nanowires,anisotropic films,mechanical rubbing,polarized light-emitting diode,photoluminescence
更新于2025-09-23 15:21:01
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High-performance and Flexible CsPbBr3UV-vis Photodetectors Fabricated via Chemical Vapor Deposition
摘要： Inorganic perovskite cesium lead halide (CsPbBr3) has attracted considerable attention because of its particularly excellent optoelectronics properties and high stability in humidity environments. Here, highly crystalline CsPbBr3 films with different morphologies and grain sizes were prepared via a one-step low pressure chemical vapor deposition (CVD). The structure-activity relationship between film microstructure and photodetectors (PDs) performance are investigated. The CsPbBr3 PD prepared at ~190 ℃ possess an excellent response in the UV-Vis region and exhibits a fast response time of 0.7 ms/1.0 ms. Under 405 nm laser irradiation, the PD has a high responsivity, detectivity, external quantum efficiency, and switch ratio of 3.49 A/W, 1.50×1013 Jones, 1075.4%, and 3.29×105, respectively. More importantly, the PD maintains 93% of original photocurrent when exposed to air for 28 days, which demonstrates excellent stability. At the same time, the CsPbBr3 films prepared via CVD are not dependent on the substrate, and the PDs exhibit similar performance on glass, SiO2/Si and polyimide (PI) substrates. The photocurrent of the flexible PD is maintained at 86% of the initial device performance parameters after 1000 bending cycles. These results indicate that the CsPbBr3 perovskite films prepared via CVD have great potential for application in high-performance, stable and flexible PDs.
关键词： photodetector,chemical vapor deposition,stability,CsPbBr3,flexible
更新于2025-09-23 15:21:01
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Enhancing the performance of LARP-synthesized CsPbBr <sub/>3</sub> nanocrystal LEDs by employing a dual hole injection layer
摘要： Lead halide perovskites have been considered promising materials for optoelectronic applications owing to their superior properties. CsPbBr3 nanocrystals (NCs) with a narrow particle size distribution and a narrow emission spectrum are synthesized by ligand-assisted re-precipitation (LARP), a low-cost and facile process. In inverted CsPbBr3 NC LEDs, a dual hole injection layer (HIL) of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN)/MoO3 is introduced to enhance hole injection and transport, because HAT-CN can extract electrons easily from the hole transport layer and leave a large number of holes there. The current and power efficiencies of the optimized device with a dual HIL are 1.5- and 1.8-fold higher than those of the single HIL device. It is believed that the dual HAT-CN/MoO3 HIL effectively promotes hole injection and has promise for application in many other devices.
关键词： Ligand-assisted re-precipitation,Optoelectronic applications,Lead halide perovskites,CsPbBr3 nanocrystals,Dual hole injection layer,HAT-CN/MoO3
更新于2025-09-23 15:21:01
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Exploring the Carrier Dynamics in Zinc Oxide-Metal Halide Based Perovskites Nanostructures: Towards Reduced Dielectric Loss and Improved Photocurrent
摘要： Metal-halide based perovskites have emerged as a potential candidate for optoelectronic applications due to their impressive performance achieved by tuning the optical/electrical properties through tailoring the perovskite nanostructures. Herein, we report the synthesis of composite nanostructures by incorporation of ZnO (~6 nm) into CsPbBr3 (CPB) perovskite framework, which has significant enhancement of photocurrent, due to efficient interfacial charge separation and reduced dielectric loss. Detailed steady state and time resolved PL studies have been carried out to understand charge transfer dynamics in CsPbBr3/ZnO nanostructure composite system. Femtosecond transient absorption and broadband dielectric spectroscopy studies were carried out to determine the charge carrier relaxation and transfer mechanism. Redox energy level diagram suggests photo-excited electron from conduction band (CB) CPB can be transferred to the CB of ZnO NP due to thermodynamic viability. Ultrafast studies reveal the electron transfer take place from the perovskite nanostructures to ZnO NP within ～500 fs and limits of the recombination process by efficient charge separation and charge accumulation at the interfaces. Dielectric studies also reveal reduced charge leakage in composite nanostructures with efficient charge separation by facilitating the charge accumulation at the interfaces. Overall, the efficient charge transfer and slow carrier recombination with reduced dielectric losses significantly improved the photocurrent behavior CsPbBr3/ZnO nanostructure composite system as desired for optoelectronic devices.
关键词： ZnO,charge transfer dynamics,optoelectronic applications,dielectric loss,photocurrent,Metal-halide based perovskites,CsPbBr3
更新于2025-09-23 15:21:01
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Vapor-deposited all inorganic CsPbBr3 thin films and interface modification with C8-BTBT for high performance photodetector
摘要： All inorganic perovskites like CsPbBr3 have attracted rising attention and are considered as promising candidates for optoelectronic devices. Here we fabricated CsPbBr3 films by co-evaporation. The as-deposited and low temperature (below 300 °C) annealed films are in a mixture phase of CsPbBr3 and CsPb2Br5. After 400 °C annealing in ambient air, the CsPbBr3 phase becomes dominant with a good crystal structure and less defects. Then, 2,7-diocty[1]benzothieno-[3,2-b]benzothiophen (C8-BTBT) was deposited on the CsPbBr3 film layer-by-layer to investigate the interface electronic structure with X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). As C8-BTBT was deposited, p-doping effect was observed at the surface of CsPbBr3 by the interface energy level alignment. At the same time, we also observed a chemical reaction at the interface and a small amount of lead sulfite might be formed. CsPbBr3 based photodetectors with or without C8-BTBT modified layer were also fabricated and studied. It was found that the photocurrent of the detectors with an additional C8-BTBT layer was about two orders of magnitude higher than that without C8-BTBT layer. The responsivities and response time are also improved with C8-BTBT. We attribute the improvement of photoelectronic properties to the interface energy level adjustment by the C8-BTBT. These results highlight the potential of C8-BTBT as a modified layer for inorganic perovskite optoelectronic devices.
关键词： CsPbBr3 films,C8-BTBT,Interfacial electronic structures,Vacuum evaporation,Photoelectronic properties
更新于2025-09-23 15:21:01
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Ethanol–water-assisted room temperature synthesis of CsPbBr3/SiO2 nanocomposites with high stability in ethanol
摘要： All-inorganic halide perovskites have attracted great attention by virtue of the merits of bright emission, tunable wavelength and narrow-band emission. Despite the excellent optical features, all-inorganic halide perovskite materials have suffered from intrinsic instability, which has limited their applications in various optoelectronic devices. To mitigate the intractable issue, we demonstrated the CsPbBr3 nanoparticles decorated with smaller SiO2 nanocrystals to passivate the surface defects; SiO2 nanoparticles were applied as a barrier layer to maintain the optical property and enhance environmental stability. A facile in situ method was proposed to prepare CsPbBr3/SiO2 nanocomposites, in which an environmental ethanol/water solvent system was needed with the addition of tetraethyl orthosilicate (TEOS) as a silicon precursor. The obtained CsPbBr3/SiO2 nanocomposites have better optical characteristic and stability than bare CsPbBr3 nanoparticles. Even 70% photoluminescence intensity of as-prepared CsPbBr3/SiO2 nanocomposites can be maintained after 168 h storage in ethanol. This newly developed synthesis will open up a new route for the fabrication of optoelectronic devices in an environmentally friendly way, and the as-obtained perovskite materials with improved stability will make them great potential for multifunctional optoelectronic devices.
关键词： Ethanol–water-assisted room temperature synthesis,All-inorganic halide perovskites,High stability,CsPbBr3/SiO2 nanocomposites,Optoelectronic devices
更新于2025-09-23 15:21:01
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The influence of electrode for electroluminescence devices based on all-inorganic halide perovskite CsPbBr<sub>3</sub>
摘要： Electroluminescence devices based all-inorganic halide perovskite material with the excellent luminescence performance have been studied extensively in recent years. However, the important role for the electrodes of electroluminescence devices is payed few attention by theoretical and experimental studies. Appropriate electrodes can reduce the Schottky barrier height to decrease the energy loss, and prevent the metal impurities from diffusing into the perovskite material to generate deep traps levels, which improves the luminous efficiency and lifetime of devices. In this paper, not only the interface effects between CsPbBr3 and common metal electrode (Ag, Au, Ni, Cu and Pt) are studied by first-principle calculations, but also the diffusion effects of metal electrode atom into the CsPbBr3 layer are also explored by nudged elastic band calculations. The calculated results show the metal Ag is more suitable for the cathode for CsPbBr3 electroluminescence devices, while the metal Pt is more applicable for the anode. Based on the overall consideration about the interface effects and diffusion effects of the CsPbBr3-metal electrode junctions, the essential principle provide a valuable reference how to select the suitable electrodes for other electroluminescence devices.
关键词： electroluminescence devices,diffusion effects,Schottky barrier height,CsPbBr3,all-inorganic halide perovskite,metal electrodes
更新于2025-09-23 15:19:57
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Enhanced UV-visible detection of InGaZnO phototransistors via CsPbBr3 quantum dots
摘要： Indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) exhibit high field-effect carrier mobility and low off-state current, which are attractive for high speed and low noise photodetectors and image sensor applications. However, with an optical band gap of ~3.3 eV, the photodetection range of IGZO TFTs is limited to short wavelength ultraviolet (UV) light. Here, we demonstrate a simple approach to enhance the performance of IGZO-based phototransistors by incorporating layers of solution-processed perovskite quantum dots (QDs) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Owing to the fast transfer of photogenerated electrons by CsPbBr3 QDs absorbing layer, the photoresponse of QD-decorated IGZO phototransistor is extended to the visible range (500 nm), and the responsivity and detectivity of QD-decorated device are more than two order higher than those of original IGZO TFTs. Moreover, the QD-decorated IGZO phototransistor also exhibits enhanced performance under UV light (350 nm), achieving a responsivity of 9.72 A/W, a detectivity of 2.96 × 1012 Jones, and a light to dark current ratio in the order of 106 at a wavelength of 350 nm (a light intensity of 207.3 μW/cm2).
关键词： heterojunction,CsPbBr3 QDs,IGZO,phototransistors
更新于2025-09-23 15:19:57
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High performance CsPbBr <sub/>3</sub> quantum dots photodetectors by using zinc oxide nanorods arrays as an electron-transport layer
摘要： The electron transport layer (ETL) in perovskite photodetectors is playing a vital role in highly efficient electron extraction. Herein, this work reports a perovskite photodetector based on hydrothermal-fabricated ZnO nanorods (NRs) as the ETL and hot-injection-fabricated CsPbBr3 quantum dot (QD) as the photoabsorber. The crystalline structure, morphologies, and photoluminescence (PL) of the materials and the physics mechanism of highly efficient electron extraction in the devices are characterized and analyzed. The PL and time-resolved PL confirm the reduced recombination and enhanced electron transport to the indium tin oxide anode. The photodetectors based on ZnO NRs/CsPbBr3 QDs exhibit enormous enhancement in the response parameters such as a rise time of 12 ms, a decay time of 38 ms, and an on/off ratio of 3000, compared with the photodetectors based on ZnO films/CsPbBr3 QDs. These results indicate that the fabricated ZnO NRs/CsPbBr3 QDs heterojunction has a wide prospect of future applications in photodetectors.
关键词： electron transport layer,photoluminescence,ZnO nanorods,perovskite photodetectors,CsPbBr3 quantum dots
更新于2025-09-23 15:19:57