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Analysis of aqueous systems using all-inorganic perovskite CsPbBr3 quantum dots with stable electrochemiluminescence performance using a closed bipolar electrode
摘要： All-inorganic perovskite CsPbX3 (X = Cl, Br, I) quantum dots (QDs) have emerged as a new class of semiconductor nanocrystals, but the stability of CsPbX3 QDs in polar solvents is still a significant challenge. Since most targets in analytical chemistry, especially for biological detection, exist in an aqueous medium, this weakness seriously hampers practical analytical applications of CsPbX3 QDs. In this work, we introduce a closed bipolar electrode (BPE) to extend the application of perovskite QDs to aqueous systems. Based on the principle of conservation of charge in the electrode reactions at opposite ends of the BPE, the concentration of H2O2 in an aqueous medium can be detected by measuring the ECL intensity of CsPbBr3 QDs in an organic solution. Thus, for the first time, H2O2 in an aqueous system has been successfully analyzed using all-inorganic perovskite CsPbBr3 QDs with stable electrochemiluminescence performance combined with a closed bipolar electrode chip.
关键词： Bipolar electrode,Electrochemiluminescence,Perovskite,CsPbBr3 QDs
更新于2025-09-11 14:15:04
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Optical temperature sensing of Eu3+-doped oxyhalide glasses containing CsPbBr3 perovskite quantum dots
摘要： A new strategy for optical thermometer with high sensitivity was developed herein by employing exciton recombination of CsPbBr3 quantum dots as temperature detecting signal and 4f→4f transition Eu3t ions as reference one. A series of structural and spectroscopic characterizations confirmed that CsPbBr3 perovskite quantum dots were successfully precipitated and Eu3t doping activators remained in glass matrix. Benefited from their completely different thermal-quenching behaviors, fluorescence intensity ratio of exciton recombination and Eu3t emission in nanocomposite exhibited excellent temperature sensing property in the temperature ranging from 93 K to 383 K. The maximum absolute and relative temperature sensitivity can reach as high as 0.0224 K-1 and 2.25% K-1, respectively. We believe that this work will exploit an effective pathway for developing innovative non-contact optical thermometric materials.
关键词： Glass,Perovskite quantum dots,Eu3t,Temperature sensing,CsPbBr3
更新于2025-09-11 14:15:04
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Effect of size on the electronic structure and optical properties of cubic CsPbBr3 quantum dots
摘要： The size effect on the electronic structure and optical properties of cubic CsPbBr3 perovskite quantum dots is investigated by using an 8-band k·p model based on effective-mass envelope function theory with exciton binding energy consideration. Quantum dots with smaller size have larger bandgaps due to quantum con?nement. The transition matrix element (TME) is also in?uenced by the size. The optical gain of such material is calculated by considering TME, Fermi factor, injected carrier density, quantum dot size, and dephasing rate. Higher density of injected carrier is needed for smaller quantum dot to get a positive optical gain. The peak of optical gain has a blue shift as the size of quantum dot decreases. When the carrier density increases for a quantum dot with certain size, a blue shift in emission peak position can be observed due to band ?lling effect. Smaller quantum dots have higher differential optical gain at carrier densities within certain range.
关键词： CsPbBr3,k·p method,Quantum Dot,Perovskite
更新于2025-09-11 14:15:04
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Growing high-quality CsPbBr <sub/>3</sub> by using porous CsPb <sub/>2</sub> Br <sub/>5</sub> as an intermediate: a promising light absorber in carbon-based perovskite solar cells
摘要： CsPbBr3 with a large band gap ((cid:1)2.3 eV) is a promising material for fabricating perovskite solar cells (PSCs) with a high open-circuit voltage (Voc) and high stability. However, a suitable method is still lacking for depositing high-quality CsPbBr3 films. Herein, we develop a novel strategy to deposit high-quality CsPbBr3 films by employing a porous CsPb2Br5 film as an intermediate layer. Highly porous CsPb2Br5 films composed of lamellar crystals were obtained by immersing Pb–Br precursor layers in a low-concentration CsBr IPA solution. The low CsBr concentration helped to widen the processing window of CsPb2Br5, while the low-polarity IPA solvent served to keep the film structure stable during the reaction. High-quality CsPbBr3 films with full coverage, high purity and low defect density were obtained by further converting the CsPb2Br5 films in a high-concentration CsBr solution. After introducing the optimized CsPbBr3 film into a carbon-based PSC without a hole transporting material (C-PSC), a power conversion efficiency (PCE) of 6.1% and a Voc of 1.38 V were achieved. Moreover, the devices without encapsulation show almost no PCE decay after 200 days of storage in ambient air (25–85% relative humidity, 20–30 (cid:3)C) and at 80 (cid:3)C (10–20% relative humidity) for over 1080 h.
关键词： CsPbBr3,perovskite solar cells,stability,porous CsPb2Br5,carbon-based
更新于2025-09-11 14:15:04
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p-GaN/n-ZnO Nanorod/CsPbBr <sub/>3</sub> Quantum Dots Decorated with ZnO Nanoseeds for Light-Emitting Diodes
摘要： In this paper, we report the dual-wavelength green-light emission from zinc oxide (ZnO)-nanoseed-decorated p-GaN (gallium nitride)/n-ZnO nanorod/CsPbBr3 quantum dots (QDs) light-emitting diodes (LEDs). At the same time, the effect of ZnO nanoseeds on the p-GaN/n-ZnO nanorod/CsPbBr3 QDs LED performance is deeply studied. ZnO nanoseeds were fabricated by magnetron sputtering and the sol?gel method; then ZnO nanorods were obtained on GaN by hydrothermal treatment to form the p-GaN/n-ZnO nanorod heterojunction, and green CsPbBr3 QDs were further deposited on ZnO nanorod arrays to realize LEDs. The results show that magnetron-sputtering ZnO nanoseeds can induce regular vertical ZnO nanorod arrays, and the corresponding device presents a better electroluminescence (EL) performance. The X-ray diffraction, atomic force microscopy, and EL mechanisms indicate that the p-GaN/n-ZnO nanorod with magnetron-sputtering ZnO nanoseeds has a better crystalline interface. Our results indicate that the p-GaN/n-ZnO nanorod/CsPbBr3 QDs heterojunction structure can be served as dual-wavelength LEDs, and magnetron-sputtering ZnO nanoseeds can give rise to a better EL performance.
关键词： CsPbBr3 quantum dots,electroluminescence,ZnO nanoseeds,ZnO nanorods,light-emitting diodes
更新于2025-09-11 14:15:04
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High-Quality All-Inorganic Perovskite CsPbBr3 Quantum Dots Emitter Prepared by a Simple Purified Method and Applications of Light-Emitting Diodes
摘要： High-quality perovskite CsPbBr3 quantum dots (QDs-CsPbBr3) were prepared using the ultrasonic oscillation method, which is simple and provides variable yield according to requirements. The emission spectra over a large portion of the visible spectral region (450–650 nm) of QD-CsPbX3 (X = Cl, Br, and I) have tunable compositions that can be halide exchanged using the halide anion exchange technique and quantum size-effects. A strong peak with high intensity of (200) lattice plane of purified QDs-CsPbBr3 film is obtained, confirming the formation of an orthorhombic perovskite crystal structure of the Pnma space group. The photoluminescence of QDs-CsPbBr3 was characterized using a narrow line-width emission of 20 nm, with high quantum yields of up to 99.2%, and radioactive lifetime increasing to 26 ns. Finally, through the excellent advantages of QDs-CsPbBr3 mentioned above, purified perovskite QDs-CsPbBr3 as an active layer was utilized in perovskite quantum dot light-emitting diodes structure applications. As a result, the perovskite QDs-CsPbBr3 light-emitting diodes (LEDs) exhibits a turn-on voltage of 7 V and a maximum luminance of 5.1 cd/m2.
关键词： all-inorganic halide perovskite,perovskite CsPbBr3,quantum dot light-emitting diodes,quantum dots
更新于2025-09-11 14:15:04
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Methylammonium-Mediated Crystallization of Cesium-Based 2D/3D Perovskite toward High-Efficiency Light-Emitting Diodes
摘要： 2D/3D perovskites have been successfully applied to high-efficiency light-emitting diodes (LEDs) due to their large exciton binding energy (Eb) caused by the quantum and dielectric confinements. Thermal annealing and antisolvent treatments are usually executed in order to promote the crystallization and film quality of perovskites, which add complexity to the device fabrication process. Here, the Cesium-based 2D/3D perovskite was prepared by introducing an ammonium halide benzamidine hydrochloride (BMCl) as the additive. By further introducing an appropriate amount of MABr and PbBr2, BM2(Cs1-xMAxPbBr3)n-1PbBr4 crystals can be formed rapidly without any additional treatments, whilst inhibiting the formation of unfavorable Cs4PbBr6 phase. The optimized 2D/3D perovskite based LEDs achieved a maximum luminance of 12367 Cd/m2, current efficiency of 17.4 Cd/A, and EQE of 5.2%. Our results suggest that appropriate perovskite crystallization can be achieved at room temperature by the regulation of precursor solution, making the perovskite crystallization process easier to control with reduced processing complexity.
关键词： CsPbBr3,light-emitting diodes,perovskite,fast crystallization,2D/3D
更新于2025-09-11 14:15:04
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Universal defects elimination for high performance thermally evaporated CsPbBr3 perovskite solar cells
摘要： Inorganic CsPbBr3 perovskite has emerged as a promising material for fabricating highly stable perovskite solar cell devices. However, during the formation of thermally evaporated CsPbBr3 film, an all-solid reaction between CsBr and PbBr2 leads to non-uniform interfaces and high defect density in the perovskite film. In this work, we utilize a two-step sintering (TSS) method which successfully modifies the morphologies of thermally evaporated CsPbBr3 films and the power conversion efficiency of a champion CsPbBr3 perovskite solar cell achieves 9.35%. Steady-state photoluminescence, time-resolved photoluminescence and space-charge-limited-current results prove that the TSS process can effectively reduce defect densities also. Besides these improvements, the TSS device maintains 94% of initial efficiency after being heated at 100°C without encapsulation for over 40 days under ambient lab condition. In comparison, the untreated device reduces about 15%. Transmission electron microscope results further prove the reduction of line defects in CsPbBr3 crystals after TSS treatment.
关键词： Two-step sintering,Defects elimination,Thermal evaporation method,All-inorganic CsPbBr3 perovskite solar cells
更新于2025-09-11 14:15:04
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Water Soluble and Bright Luminescent Cesium Lead Bromide Perovskite Quantum Dot-Polymer Composites for Tumor-Derived Exosomes Imaging
摘要： Cesium-lead-halide perovskite quantum dots (PQDs), are a highly promising class of next-generation optical material for bio-imaging applications. Herein, we present a nanocomposite strategy for the design of water soluble, highly luminescence CsPbBr3 PQD nanocomposites without modifying the crystal symmetry and photoluminescence (PL) property. Water soluble PQDs are reproducibly synthesized via encapsulating CsPbBr3 PQDs with polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (PS-PEB-PS) and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol (PEG-PPG-PEG). In the reported design, the polystyrene triblock polymers strongly interact with the hydrophobic parts of PQDs and the water-soluble PEG moiety acts as protection layer to effectively prevent degradation of PQDs in water. Outer shell PEG layer also helps to develop biocompatible PQDs. Reported data indicate that encapsulating CsPbBr3 PQDs with polymer helps to improve the photoluminescence quantum yield (PLQY) from 83% to 88%, which may be due to decrease in the surface defects after the effective polymer coating. Experimental data show that PL intensity from CsPbBr3 PQD nanocomposites remain unchanged even after 30 days of exposure in air. Similarly, reported data indicate that nanocomposites retain their luminescence properties in water for first 8 days and then decreases slowly to 60% of its initial PL intensity after one month. On the other hand, the PL emission for the PQD without polymer encapsulation is completely quenched within few hours. Exosomes are highly promising avenue for accessing tumor type and stage and to monitor cancer treatment response. Reported data reveal that anti-CD63 antibody attached PQD nanocomposites are capable of tracking of triple negative MDA-MB-231 breast tumor derived exosomes via binding using anti- CD63 antibody and selective green luminescence imaging using PQD nanocomposites.
关键词： selective imaging of exosomes,Triple negative breast tumor derived exosomes,water soluble perovskite nanocomposites,Air stable CsPbBr3 quantum dots,Green luminescence imaging
更新于2025-09-11 14:15:04
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Vapor-Phase Growth of CsPbBr <sub/>3</sub> Microstructures for Highly Efficient Pure Green Light Emission
摘要： All-inorganic lead halide perovskites have been extensively studied in the past several years due to their superior stability against moisture, oxygen, light, and heat compared with their organic–inorganic counterparts. CsPbBr3 with suitable band gap and ultrahigh photoluminescence quantum yield is a promising candidate for pure green emitter in the backlighting display to fill the so-called “green gap.” Here, vapor-phase growth of CsPbBr3 microspheres is reported for highly efficient pure green light emission. The as-synthesized microspheres exhibit a stronger photoluminescence (PL) intensity with a photoluminescence quantum yield of 75% resulting from the lower energy of longitudinal optical phonons revealed by temperature dependent PL studies. Importantly, with the diameter increasing from 2 to 50 μm the PL peak positions of the microspheres can be readily tuned from 527 to 539 nm, well filling the so-called “green gap.” The red-shift with increasing diameter can be ascribed to the reabsorption process during the photon propagation inside the microspheres. The studies provide a route to improve the photoluminescence quantum yield in all-inorganic lead halide perovskites, but also suggest an alternative approach to achieve the pure green emission for the backlighting display.
关键词： LO phonon,CsPbBr3,microspheres,reabsorption,pure green emission
更新于2025-09-10 09:29:36