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Controlled Growth of CH <sub/>3</sub> NH <sub/>3</sub> PbBr <sub/>3</sub> Perovskite Nanocrystals via a Water–Oil Interfacial Synthesis Method
摘要： Fundamental insights into the reaction kinetics of organic–inorganic lead halide perovskite nanocrystals (LHP NCs) are still limited due to their ultrafast formation rate. Herein, we develop a water–oil interfacial synthesis of MAPbBr3 NCs (MA = CH3NH3+), which prolongs the reaction time to tens of minutes. This method makes it possible to monitor in situ the formation process of MAPbBr3 NCs and observe successive spectral evolutions from 438 to 534 nm in a single reaction by extending reaction time. The implementation of this method depends on reducing the formation rate of PbBr64? octahedra and the diffusion rate of MA. The formation of PbBr64? is a rate-determining step, and the biphasic system offers a favorable reaction condition to control the mass transfer of MA. The effects of temperature and concentration of precursor and ligand are investigated in detail.
关键词： CH3NH3PbBr3,perovskite nanocrystals,interfacial synthesis,kinetic study,formation mechanisms
更新于2025-09-19 17:13:59
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Microfibers Doped with Perovskite Nanocrystals for Ultralow-Loss Waveguides
摘要： Low loss optical waveguides have attracted intense interests as the building blocks for photonic devices and integrated circuits. Herein, we employed the all-inorganic halide perovskite nanocrystals (IHPNs) doped polymer microfibers for developing the active waveguides for the first time. We reveal that the absorption coefficient (2.6 cm-1) of the CsPbBr3 IHPNs-doped polymer fibers is one order of magnitude lower than that of traditional CdSe quantum dots (QDs)-based microfibers, which can be attributed to the much higher photoluminescence quantum yield of IHPNs. Moreover, manganese ions (Mn2+) were successfully inserted into CsPbX3 IHPNs to engineer the Stokes shift and eliminate the reabsorption effect. As a result, the Mn:CsPb(Br/Cl)3 IHPNs-doped polymer microfibers exhibited a record-low absorption coefficient of 0.33 cm-1. These findings reveal a great potential of perovskite nanocrystals in photonic technologies that also paves the way for solution-processed QDs in low-loss and long-range optical guiding.
关键词： Stokes shift,perovskite nanocrystals,polymer microfibers,Low-loss waveguides,ion doping
更新于2025-09-16 10:30:52
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Photo- and electroluminescence features of films and field effect transistors based on inorganic perovskite nanocrystals embedded in a polymer matrix
摘要： The optical and electrical properties of films and field-effect transistors (FETs) based on pure MEH-PPV, neat CsPbBr3 nanocrystals (NCs), and MEH-PPV:CsPbBr3 NCs composites with different contents of CsPbBr3 NCs are investigated. The films were characterized by absorbance, atomic-force microscope and current-voltage characteristics (I-Vs) techniques. Relative PL and EL intensities and PL spectra of the pure MEH-PPV, neat CsPbBr3 NCs and MEH-PPV:CsPbBr3 NCs films were measured at 300 K at various levels of optical and electrical excitation power; these dependencies of the PL and EL intensities turned out to be sublinear and superlinear respectively. FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films exhibit I-Vs at 290 – 100 K a dominant hole transport mechanism. The mobility of charge carriers was determined at 290 K for neat CsPbBr3 NCs (for electrons: 2.7 10-2 cm2/Vs) and MEH-PPV:CsPbBr3 NCs (1:1) (for holes: 9 cm2/Vs). The temperature dependence of the hole mobility μFET(T) of FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films characteristic of the hopping mode. It was found that the superlinearity of the dependence of EL of MEH-PPV:CsPbBr3 NCs LE-FETs at 290 K increases with increasing concentration of CsPbBr3 NCs due to efficient energy transfer between CsPbBr3 NCs and the MEH-PPV polymer matrix, and also because of the probability of electron tunneling through the potential barrier to electrode. It is expected that the obtained MEH-PPV:CsPbBr3 NCs nanocomposite films will be useful for efficient applications in nanotechnology LEDs, FETs and LE-FETs.
关键词： Energy transfer,Field-effect transistors,Semiconducting polymers,Photo- and electroluminescence,Charge carrier mobility,Inorganic perovskite nanocrystals
更新于2025-09-16 10:30:52
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Three-Dimensional Laser-Assisted Patterning of Blue-Emissive Metal Halide Perovskite Nanocrystals inside a Glass with Switchable Photoluminescence
摘要： The high-precision patterning of metal halide perovskites (MHPs) is of paramount importance for their device application. Here, we demonstrate the femtosecond (fs)-laser-assisted formation of three-dimensional MHP nanocrystal (NC) patterns with strong blue photoluminescence (PL) inside an oxide glass. Our strategy enables the crystallization and erasing of CsPb(Cl/Br)3 NCs inside a glass localized around the laser focal area through a combination of fs laser irradiation and thermal treatment processes. These recoverable patterns exhibit a switchable PL associated with the laser-induced defect and the thermal healing of MHP NCs that are benefits from the soft ionic crystal structure and low formation energy of the MHPs. Due to the high stability offered by the protection of the oxide glass matrix, the laser printing of fine-structured MHP micropatterns can be repeated over multiple cycles with a high robustness compared with their colloidal process counterparts. Our results demonstrate a simple strategy for creating emissive patterns inside a stable and transparent solid matrix that could be promising for applications including information storage, three-dimensional displays, anticounterfeit labels, and information security protection.
关键词： three-dimensional patterning,perovskite nanocrystals,reversible photoluminescence,laser-assisted crystallization,femtosecond laser processing
更新于2025-09-16 10:30:52
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Ligand induced anomalous emission shift of size-controlled CsPbBr <sub/>3</sub> nanocrystals
摘要： CsPbX3 perovskite nanocrystals (NCs) have attracted much attention from researchers because of their excellent photoelectric properties like high quantum yield, large absorption cross section, and simple preparation process. The addition of ligands in the synthesis process has a significant effect on the microstructure and photophysical properties of solution-processed NCs, which needs further extensive studies. In this Letter, the effects of ligand electronegativity on the size and photoluminescence (PL) properties of CsPbBr3 NCs were reported. One is typical oleic acid with weak electronegativity, and another is 2-acrylamide-2-methylpropionic sulfonic acid with strong electronegativity. The third is their typical mixture with a molar ratio of 1:1. With the increase in ligand electronegativity, the size of CsPbBr3 NCs increases significantly. However, in contrast to the traditional quantum size confinement effect, the PL peak exhibits an abnormal blue shift gradually and the ligand passivation effect on NC surface defects also becomes more significant. The physical mechanism of this anomalous PL shift phenomena of CsPbBr3 NCs was investigated using the time-resolved PL spectrum and transient absorption spectrum.
关键词： transient absorption spectrum,quantum size confinement,photoluminescence,CsPbX3 perovskite nanocrystals,ligand electronegativity,time-resolved PL spectrum
更新于2025-09-16 10:30:52
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Modulation of Ligands Conjugation for Efficient FAPbBr3 based Green Light-Emitting Diodes
摘要： Organic ligands capped on surface of perovskite nanocrystals (PeNCs) strongly influence the optical and electrical properties of the obtained PeNCs films, which are fundamental for efficient perovskite light-emitting diodes (PeLEDs). Here, we investigate the ligands effect through introduction of ligands with strong π conjugation, 1-(1-naphthyl)ethylamine bromide (NEABr), for the fabrication of FAPbBr3 PeNCs. Compared to the widely applied ligands of phenylethylamine bromide (PEABr), NEABr molecules containing naphthalene ring possess more delocalized electrons and better conductivity, which is beneficial for charge injection and transportation between interfaces. By varying the ligands ratio, high quality three dimensional FAPbBr3 PeNCs films with photoluminescence quantum yields up to 80% are fabricated. Based on the optimized PeNCs films, electroluminescent (EL) devices achieve a maximum external quantum efficiency of 8.6%, which is about three times higher than that of EL devices based on PEABr. Importantly, through understanding into the ligands effect, we demonstrate that the enhanced device efficiency is attributed to lower defect densities and decreased interfacial resistance in NEABr derived EL devices. Our findings about ligands conjugation on device performance may benefit other perovskites based optoelectronic devices.
关键词： ligands conjugation,perovskite nanocrystals,light-emitting diodes,charge injection,FAPbBr3
更新于2025-09-16 10:30:52
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Pink all-inorganic halide perovskite nanocrystals with adjustable characteristics: Fully reversible cation exchange, improving the stability of dopant emission and light-emitting diode application
摘要： In this work, we proposed a straightforward and effective strategy for preparing pink all-inorganic halide perovskite nanocrystal (NC) phosphors for light-emitting diode (LED) application. The pink perovskite NCs with varying Mn contents could be easily and steadily obtained via postsynthetic ion exchange at room temperature. The dependence of the size and optical properties of pink NCs on dopant content was systematically investigated. The reversible anion exchange processes of pink perovskite NCs were conducted with halide salts containing or excluding Pb. The contrasting results suggested that the irreversibility of Mn-emission was mainly affected by the fully reversible cation exchange between Pb2+ and Mn2+. The pink NCs with better stability of dopant emission and high monodispersity were successfully developed by compounding with silica. A pink LED was further made by using the pink NCs/silica composites as pink phosphors on a 395 nm InGaN LED chip. This work provides a feasible strategy for the fabrication of pink LEDs, which may have great application prospects in the field of special lighting, like neon lights and plant growth lights.
关键词： light-emitting diodes,anion exchange,perovskite nanocrystals,stability,cation exchange
更新于2025-09-12 10:27:22
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Porous single-wall carbon nanotube templates decorated with all-inorganic perovskite nanocrystals for ultra-flexible photodetectors
摘要： As an inevitable optoelectronic material with unique properties, halide perovskites attracted increasing attention in recent years. Meanwhile, hybridization of nanostructured perovskites with one-dimensional (1D) or two-dimensional (2D) functional materials has exhibited unique applications in nanotechnology. In this communication, a highly conducting porous single-wall carbon nanotube (p-SWCNT) template decorated with phase-pure CsPbBr3 nanocrystals by simple solution-phase technique was demonstrated, and the ultra-flexible photodetector Au/p-SWCNT:CsPbBr3/Au showed high sensitivity even in highly bending state. Also, the mechanism of wetting CsPbBr3 along p-SWCNT and the detailed fabrication process for ultra-flexible photodetectors were highlighted. The direct contact (in-situ) on p-SWCNT by crystallization of perovskite precursor can enhance the charge transfer at their interface effectively. At applied bias of +5 V, the optimized photodetector Au/p-SWCNT:CsPbBr3/Au exhibits a maximum photoresponsivity of 41.0 AW-1 with a specific detectivity of 1.67×1012 Jones under an incident 232 μW/cm2 520 nm illumination. In addition, it exhibits excellent mechanical and electrical properties even under high strain (i.e. bending angle up to -17°) and recovers the original performance after repeated bending cycles upto 1000 times. Our experimental results showed that such a hybrid materials provide a promising method for rigid and flexible optoelectronic devices.
关键词： Porous single-wall carbon nanotube (p-SWCN),inorganic perovskite nanocrystals,flexible photodetector,CsPbBr3,visible light photodetector
更新于2025-09-12 10:27:22
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Swelling‐Deswelling Microencapsulation‐Enabled Ultrastable Perovskite?Polymer Composites for Photonic Applications
摘要： Metal halide perovskite nanocrystals are emerging as novel optoelectronic materials. Owing to their excellent optical and electronic properties such as tunable band gap, narrow-band emission and high charge mobility, they are quite promising in various fields including liquid-crystal display backlighting, solid-state lighting and other energy conversion applications. However, the intrinsic low formation energy makes them vulnerable to external stimulus, e. g. water, oxygen, heat, etc. Among many methods, swelling-deswelling microencapsulation emerges as one of the most promising strategies to improve their stability. Herein, recent developments and future research directions in swelling-deswelling microencapsulation-enabled ultrastable perovskite(cid:0) polymer composites are summarized. We believe this strategy has great potential to deliver successful perovskite-based commercial products for many photonics applications.
关键词： ultra-stable,perovskite nanocrystals,polymer,swelling-deswelling microencapsulation,photoluminescence
更新于2025-09-12 10:27:22
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Charge Transport between Coaxial Polymer Nanorods and Grafted All-Inorganic Perovskite Nanocrystals for Hybrid Organic Solar Cells with Enhanced Photoconversion Efficiency
摘要： The versatile optoelectronics properties of perovskite nanocrystals (NCs) have provided a strong surge for their utilization in different classes of solar cells, organic photovoltaic (OPV) systems being no exception. In an unprecedented approach, a hybrid solar cell with CsPbBr1.5I1.5 NCs strategically grafted on poly(3-hexylthiophene-2,5-diyl) (P3HT) nanorods (NRs) is shown to have a photoconversion efficiency (PCE) of 9.72 ± 0.4 %, with only 1.5 wt% NCs. The improvement is twice more than the P3HT:PCBM reference devices (4.09 ± 0.2 %). The choice of NC composition is validated by Density Functional Theory (DFT) calculations which show decent charge carrier mobility in CsPbBr1.5I1.5, besides having better stability than CsPbI3, making CsPbBr1.5I1.5 NCs suitable contender for hybrid device architecture. A trivial blending of the NCs in P3HT:PCBM matrix results in their non-uniform distribution, escalating charge carrier trapping, albeit maintaining a device efficiency of 8.07 ± 0.3 % with 1 wt% NCs. Uniform NC grafting is propitious over inhomogeneous blending since CsPbBr1.5I1.5 NCs not only act as additional light harvesters, but their chemical grafting onto the P3HT NRs improves the charge transport by creating better charge percolation pathways. The higher crystallinity of the P3HT NRs than P3HT also helps in reducing the trap states.
关键词： P3HT nanorods,charge transport,perovskite nanocrystals,photoconversion efficiency,hybrid solar cells
更新于2025-09-12 10:27:22