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[IEEE 2018 International Conference on Recent Innovations in Electrical, Electronics & Communication Engineering (ICRIEECE) - Bhubaneswar, India (2018.7.27-2018.7.28)] 2018 International Conference on Recent Innovations in Electrical, Electronics & Communication Engineering (ICRIEECE) - Perovskite Quantum Dots Embedded in PMMA Matrix for Resistive Switching Device
摘要： In this work, we have fabricated CH3NH3PbBr3 perovskite quantum dots embedded in PMMA matrix-based memory device. Resistive switching phenomenon was detected in this perovskite quantum dots and polymer composite. The ON/OFF current ratio was measured to be larger than 102 as well as good reproducibility and reliability. Our research paves a way to utilize organolead halide perovskite quantum dots for non-volatile memory applications.
关键词： nonvolative memory,perovskite,quantum dots
更新于2025-09-23 15:19:57
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Highly Stable Alla??Inorganic Perovskite Quantum Dots Using a ZnX <sub/>2</sub> a??Trioctylphosphinea??Oxide: Application for Higha??Performance Fulla??Color Lighta??Emitting Diode
摘要： Perovskite is a very promising material that is being extensively studied at the bulk and nanosize scales because it has outstanding optical properties, including high quantum efficiency and narrow emission spectra. However, perovskite has stability issues related to heat, air, and light. To overcome these, highly stable perovskite quantum dots (PeQDs) are developed using excess Zn precursor and trioctylphosphine-oxide (TOPO). In particular, it is clarified that Zn and TOPO are combined and these complexes are attached to the surface of the PeQDs through 31P NMR. They not only have high quantum efficiency and sharp full width at half maximum values (15–30 nm) but also have improved long-term stability at high temperature. Additionally, XPS measurements are conducted for a detailed surface analysis of PeQDs, finding that the TOPO-Zn complex effectively decrease PbO bonding in the lattice. Perovskite full-color electroluminescence (EL) devices are fabricated using PeQDs and 9,9-bis[4-[(4-ethenylphenyl)methoxy]phenyl]-N2,N7-di-1-naphthalenyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine (VB-FNPD) as a new cross-linkable hole transporting material. The VB-FNPD has a high-hole carrier mobility compared to the PVK as conventional hole-transporting layer. As a result of EL performance, they have high EQE (%) and current efficiency (Cd A?1) of (7.12%, 9.93 Cd A?1) for red, (6.06%, 32.5 Cd A?1) for green, and (0.56%, 0.88 Cd A?1) for blue-emitting devices, respectively.
关键词： TOPO-Zn precursor,electroluminescence,perovskite quantum dots,VB-FNPD
更新于2025-09-23 15:19:57
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Quantum dots on demand
摘要： The ability to create and erase three-dimensional patterns of perovskite quantum dots in glass using a femtosecond laser could bring new opportunities in displays, security marking and data storage.
关键词： displays,femtosecond laser,data storage,security marking,perovskite quantum dots
更新于2025-09-19 17:13:59
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Spectrally Tunable and Stable Electroluminescence Enabled by Rubidium Doping of CsPbBr <sub/>3</sub> Nanocrystals
摘要： Perovskite nanocrystals exhibit high photoluminescence quantum yields (PLQYs) and tunable bandgaps from ultraviolet to infrared. However, blue perovskite light-emitting diodes (LEDs) suffer from color instability under applied bias. Developing narrow-bandwidth deep-blue emitters will maximize the color gamut of display technologies. Mixed anion approaches suffer from halide segregation that leads to their spectral instability. Here instead, a mixed cation strategy is employed whereby Rb+ is directly incorporated during synthesis into CsPbBr3 nanocrystals. Blue-emitting perovskite quantum dots (QDs) with stable photoluminescence, PLQYs greater than 60%, tunable emission from 460 to 500 nm, and narrow emission linewidths (<25 nm) are reported. The strategy retains a pure bromine crystal structure resulting in color-pure stable electroluminescence at operating voltages of up to 10 V, peak external quantum efficiencies (EQEs) of 0.87% and 0.11% for sky-blue (490 nm), and deep-blue (464 nm) devices. The sky-blue devices exhibit the highest combined luminance of 93 cd m?2 at an EQE of 0.75%, the best reported to date of perovskite QD LEDs.
关键词： perovskite quantum dots,LEDs,light-emitting diodes,halide perovskites,blue emission
更新于2025-09-19 17:13:59
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Extent of Shallow/Deep Trap States beyond the Conduction Band Minimum in Defect-Tolerant CsPbBr <sub/>3</sub> Perovskite Quantum Dot: Control over the Degree of Charge Carrier Recombination
摘要： Perovskite quantum dots (PQDs) are known to be defect tolerant possessing clean band-gap with optically inactive benign defect states. However, we show that there exists significant deep trap states beyond conduction band minimum, although the extent of shallow trap states is observed to be minimal. Extent of deep trap states beyond conduction band minimum seem to significant in PQD, however the extent is less than even optically robust CdSe and InP based core/alloy-shell QDs. In-depth analyses based on ultrafast transient absorption and ultrasensitive single particle spectroscopic investigations decode the underlying degree of charge carrier recombination in CsPbBr3 PQD which are quite important for energy applications.
关键词： Perovskite quantum dots,ultrafast transient absorption,defect tolerant,single particle spectroscopy,charge carrier recombination,trap states
更新于2025-09-19 17:13:59
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Synergistic Effects of Charge Transport Engineering and Passivation Enabling Efficient Inverted Perovskite Quantum-dot Light-emitting Diodes
摘要： All inorganic perovskite quantum dots (QDs) have attracted much attention in the optoelectronic devices due to their fascinating properties such as high photoluminescence quantum yields (PLQYs), narrow emission peak, and facile synthesis process. Herein, we report a synergistic strategy of interfacial engineering and passivation. We construct an inverted device structure with Zinc Magnesium Oxide (Zn0.95Mg0.05O) as electron transport layer and p-n charge generation junction of (N,N’-Bis(naphthalen-1-yl)- N,N’- bis(phenyl) benzidine/ 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile) as hole transport layer to facilitate and balance the charge injection/transport. Meanwhile, a facile post-passivation technique is employed to passivate the cesium lead bromide (CsPbBr3) QDs via supplement of Br anion. The treated QDs exhibit improve PLQY due to decreased surface defect sites and enhanced radiative recombination. As a result, our perovskite quantum dot light-emitting diodes (PVQDLEDs) obtain a maximum luminance of 75792 cd m-2, an extremely low turn-on voltage of 1.9 V, and a maximum external quantum efficiency (EQE) of 5.95%, leading to an increase in EQE by 100% compared with that of the control device. Our work offers an effective approach to improve the performance of PVQDLEDs via multiple effects for the application of displays and solid-state lighting.
关键词： perovskite quantum dots,inverted device structure,passivation,light-emitting diodes,charge transport engineering
更新于2025-09-19 17:13:59
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Recent Progress and Development in Inorganic Halide Perovskite Quantum Dots for Photoelectrochemical Applications
摘要： Inorganic halide perovskite quantum dots (IHPQDs) have recently emerged as a new class of optoelectronic nanomaterials that can outperform the existing hybrid organometallic halide perovskite (OHP), II–VI and III–V groups semiconductor nanocrystals, mainly due to their relatively high stability, excellent photophysical properties, and promising applications in wide-ranging and diverse fields. In particular, IHPQDs have attracted much recent attention in the field of photoelectrochemistry, with the potential to harness their superb optical and charge transport properties as well as spectacular characteristics of quantum confinement effect for opening up new opportunities in next-generation photoelectrochemical (PEC) systems. Over the past few years, numerous efforts have been made to design and prepare IHPQD-based materials for a wide range of applications in photoelectrochemistry, ranging from photocatalytic degradation, photocatalytic CO2 reduction and PEC sensing, to photovoltaic devices. In this review, the recent advances in the development of IHPQD-based materials are summarized from the standpoint of photoelectrochemistry. The prospects and further developments of IHPQDs in this exciting field are also discussed.
关键词： photovoltaic devices,PEC sensing,inorganic halide perovskite quantum dots,photocatalysis,photoelectrochemical applications
更新于2025-09-19 17:13:59
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Enhancing Charge Carrier Delocalization in Perovskite Quantum Dot Solids with Energetically Aligned Conjugated Capping Ligands
摘要： Compared to bulk perovskites, charge transport in perovskite quantum dot (PQD) solids is limited. To address this issue, energetically aligned capping ligands were used to prepare methylammonium lead bromide (MAPbBr3) PQDs towards enhancing surface charge carrier density in PQD solids. Trans-cinnamic acid (TCA) and its derivates, functionalized with electron-donating or electron-withdrawing groups to modulate energy levels, are used as passivating exciton-delocalizing ligands (EDLs) to decrease the energy gap with respect to the PQD core. 3,3-diphenylpropylamine (DPPA) ligand is shown to stabilize EDLs on the PQD surface through π-π stacking intermolecular interaction, mitigating charge trapping and non-radiative decay. Passivation using EDLs in combination with DPPA increases the photoluminescence (PL) quantum yield (QY) (90%), photoconductivity, extraction, mobility, transport time, and lifetime of charge carriers in PQD solids. Prototype PQD-based light-emitting diodes (LEDs) were demonstrated with a low turn-on voltage of 2.5 V.
关键词： charge transport,light-emitting diodes,capping ligands,perovskite quantum dots,photoluminescence
更新于2025-09-19 17:13:59
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Room temperature synthesis of cesium lead bromide perovskite magic sized clusters with controlled ratio of carboxylic acid and benzylamine capping ligands
摘要： We demonstrate the synthesis of cesium lead bromide (CsPbBr3) perovskite magic sized clusters (PMSCs) and how to control the transformation from CsPbBr3 perovskite quantum dots (PQDs) to PMSCs by varying the amount of organic carboxylic acids (CAs), including mesitylacetic acid (MAA), oleic acid (OA), and phenylacetic acid (PAA), along with benzylamine (BZA) as capping ligands at room temperature. The PQDs and PMSCs are characterized by means of XRD, UV/vis, photoluminescence (PL), time-resolved PL (TRPL), and X-ray-photoelectron spectroscopy (XPS). The concentration of CAs affects the excitonic absorption of both the CsPbBr3 PMSCs (λ ? 389–428 nm) and CsPbBr3 PQDs (λ ? 460–516 nm), with high concentration of CAs favoring CsPbBr3 PMSCs over PQDs. With PAA at 45.45 mM, pure CsPbBr3 PMSCs can be generated, which does not happen for MAA or OA, suggesting that PAA is a stronger ligand than MAA and OA. The results suggest that PMSCs require better passivation or stronger ligands than PQDs. This study establishes a simple and general method for synthesizing CsPbBr3 PMSCs using a combination of BZA and CA capping ligands as a highly effective dual passivation system.
关键词： Controlled ratio of capping ligands,Room temperature,Perovskite quantum dots (PQDs),Perovskite magic sized clusters (PMSCs),Cesium lead bromide perovskite
更新于2025-09-16 10:30:52
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Facile synthesis of durable perovskite quantum dots film with near unity photoluminescence quantum yield for efficient perovskite light emitting diode
摘要： In this work, a bright uniform PSK QDs film is synthesized in-situ using an amorphous polymer and optimizing the stoichiometry. The in-situ formed QDs film grown in the presence of poly(vinylpyrrolidone) chains shows a photoluminescence quantum yield (PLQY) as high as 98% even under low light intensities (0.01mW/cm2) with a long shelf lifetime of up to 2 years under ambient light (nanocrystals retain 100% of the initial PLQY). The near unity PLQY is due to the passivation of the surface defects of the PSK QDs by the Lewis base pyrrolidone groups of the polymer chain. Further, the QDs film shows higher thermal stability that increases by a factor of more than 5 compared to the bulk film. High efficient green perovskite light-emitting diodes (PLEDs) are fabricated without electron transporting layer using the high luminescent in situ synthesized low roughness QDs film with a current efficiency of 48.18 cd/A and power efficiency of 6.88 lm/W. Such devices start emitting green light at 2.5V and reach a maximum luminance of 124727 cd m?2 at 7V with external quantum efficiency of 10.5%. Further, the flexible PLED based on PSK QDs yields a maximum luminance of 43990 cd m-2 at 7V.
关键词： Perovskite quantum dots,perovskite light emitting diode,in situ synthesis
更新于2025-09-16 10:30:52