A5024388859- Quantum Dots Synthesis And Properties
- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Dark Matter and Cosmic Phenomena
- Luminescence and Fluorescent Materials
- Solar and Space Plasma Dynamics
- Luminescence Properties of Advanced Materials
- Geomagnetism and Paleomagnetism Studies
- ECG Monitoring and Analysis
- EEG and Brain-Computer Interfaces
- Silicon Nanostructures and Photoluminescence
- Astrophysics and Cosmic Phenomena
- Non-Invasive Vital Sign Monitoring
- Ionosphere and magnetosphere dynamics
- Semiconductor materials and devices
- Sulfur-Based Synthesis Techniques
- ZnO doping and properties
- Radical Photochemical Reactions
- Advanced Semiconductor Detectors and Materials
- Nuclear Physics and Applications
- Nanoplatforms for cancer theranostics
- Organic Light-Emitting Diodes Research
- Indoor and Outdoor Localization Technologies
- Astro and Planetary Science
- Gait Recognition and Analysis
University of Toronto
2022-2025
Chinese Academy of Sciences
2002-2024
Aerospace Information Research Institute
2020-2024
University of Chinese Academy of Sciences
2020-2024
University of New Brunswick
2024
Dalian Institute of Chemical Physics
2022
State Key Laboratory of Transducer Technology
2020-2022
University of California, Riverside
2016-2021
Riverside
2016-2021
Institute of Electronics
2020
Blue perovskite light-emitting diodes (LEDs) have shown external quantum efficiencies (EQEs) of more than 10%; however, devices that emit in the true blue—those accord with emission wavelength required for Rec. 2100 primary blue —have so far been limited to EQEs ~6%. We focused here on emitting CsPbBr 3 colloidal nanocrystals (c-NCs), finding early studies they suffer from a high charge injection barrier, problem exacerbated films containing multiple layers nanocrystals. introduce...
Herein we report the first example of nanocrystal (NC) sensitized triplet–triplet annihilation based photon upconversion from visible to ultraviolet (vis-to-UV).
Hybrid organic:inorganic materials composed of semiconductor nanocrystals functionalized with acene ligands have recently emerged as a promising platform for photon upconversion. Infrared light absorbed by nanocrystal excites charge carriers that can pass to surface-bound acenes, forming triplet excitons capable fusing produce visible radiation. To fully realize this scheme, energy transfer between and acenes must occur high efficiency, yet the mechanism process remains poorly understood....
Abstract A relatively new addition to the application portfolio of lead halide perovskites is photosensitize molecular triplets for a variety photochemical applications. Here we report visible‐light‐driven isomerization and cycloaddition organic molecules sensitized by spectrally‐tunable perovskite nanocrystals. We first demonstrate with stilbene as substrate molecule that photoisomerization can proceed efficiently rapidly either directly grafting carboxylated onto nanocrystal surfaces or...
Recent years have seen a growing interest in developing heavy-metal-free colloidal quantum dots (QDs), such as InP, Si, and CuInS2, sensitizers for photochemistry. None of these materials, however, could cover the blue part spectrum applications blue-to-ultraviolet photon upconversion that is particular photocatalysis. Herein we report blue-emitting ZnSe/ZnS core/shell QDs molecular triplet down to <320 nm region (ultraviolet-B). The system consists carboxylated biphenyl transmitter ligands...
III-V colloidal quantum dots (CQDs) are promising materials for optoelectronic applications, they avoid heavy metals while achieving absorption spanning the visible to infrared (IR). However, covalent nature of CQDs requires development new passivation strategies fabricate conductive CQD solids optoelectronics: this work shows herein that ligand exchanges, previously developed in II-VI and IV-VI employing a single ligand, do not fully passivate CQDs, curtails device efficiency. Guided by...
In the III-V family of colloidal quantum dot (CQD) semiconductors, InSb promises access to a wider range infrared wavelengths compared many light-sensing material candidates. However, achieving necessary size, size-dispersity, and optical properties has been challenging. Here synthetic challenges associated with CQDs are investigated it is found that uncontrolled reduction antimony precursor hampers controlled growth CQDs. To overcome this, strategy combines nonpyrophoric precursors zinc...
Abstract Heavy‐metal‐free III–V colloidal quantum dots (CQDs) are promising materials for solution‐processed short‐wave infrared (SWIR) photodetectors. Recent progress in the synthesis of indium antimonide (InSb) CQDs with sizes smaller than Bohr exciton radius enables quantum‐size effect tuning band gap. However, it has been challenging to achieve uniform InSb gaps below 0.9 eV, as well control surface chemistry these large‐diameter CQDs. This has, date, limited development CQD...
Photon upconversion employing semiconductor nanocrystals (NCs) makes use of their large and tunable absorption to harvest light in the near-infrared (NIR) wavelengths as well small gap between singlet triplet excited states reduce energy losses. Here, we report highest QY (11.8%) thus far for conversion NIR yellow photons by improving quality PbS NC. This high was achieved using highly purified lead thiourea precursors. is 2.6 times higher than from NCs prepared with commercially available...
Quantum dot (QD)-sensitized photon upconversion follows a multi-step energy transfer process from the QD to transmitter ligand soluble annihilator. Using novel 10-R-anthracene-1,8-diphosphoric acid (R = octyl, 2-hexyldecyl, phenyl) with high binding affinity for CdSe surfaces, we demonstrate that is limited by annihilator efficiency. 1H NMR spectroscopy, these bidentate diphosphate ligands rapidly and irreversibly displace two carboxylate ligands. These mediate photoexcited QDs triplet...
Abstract Solution‐processed photodetectors based on colloidal quantum dots (CQDs) are promising candidates for short‐wavelength infrared light sensing applications. Present‐day CQD employ a active layer sandwiched between carrier‐transport layers in which the electron‐transport (ETL) is composed of metal oxides. Herein, new class ETLs developed using n‐type CQDs, finding that these benefit from quantum‐size effect tuning band energies, as well surface ligand engineering. Photodetectors...
Solution-processed colloidal quantum dots (CQDs) are promising materials for photodetectors operating in the short-wavelength infrared region (SWIR). Devices typically rely on CQD-based hole transport layers (HTL), such as CQDs treated using 1,2-ethanedithiol. Herein, we find that these HTL exhibit low carrier mobility, limiting photodiode response speed. We develop instead inverted (p-i-n) SWIR at 1370 nm, employing NiOx HTL, ultimately enabling 4× shorter fall times photodiodes (∼800 ns...
Indium phosphide (InP) quantum dots have enabled light-emitting diodes (LEDs) that are heavy-metal-free, narrow in emission linewidth, and physically flexible. However, ZnO/ZnMgO, the electron-transporting layer (ETL) high-performance red InP/ZnSe/ZnS LEDs, suffers from high defect densities, quenches luminescence when deposited on InP, induces performance degradation arises due to trap migration ETL InP emitting layer. We posited formation of Zn2+ traps outer ZnS shell, combined with sulfur...
Abstract Quantum dot (QD) light‐emitting diodes (QLEDs) are promising for next‐generation displays, but suffer from carrier imbalance arising lower hole injection compared to electron injection. A defect engineering strategy is reported tackle transport limitations in nickel oxide‐based inorganic hole‐injection layers (HILs) and find that able enhance high‐performance InP QLEDs using the newly designed material. Through optoelectronic simulations, how electronic properties of NiO x affect...
Abstract Heavy‐metal‐free III–V colloidal quantum dots (CQDs) are promising materials for solution‐processed short‐wave infrared (SWIR) photodetectors. Recent progress in the synthesis of indium antimonide (InSb) CQDs with sizes smaller than Bohr exciton radius enables quantum‐size effect tuning band gap. However, it has been challenging to achieve uniform InSb gaps below 0.9 eV, as well control surface chemistry these large‐diameter CQDs. This has, date, limited development CQD...
Quantum dot light-emitting diodes (QD-LEDs) with stable high efficiencies are crucial for next-generation displays. However, uncontrollable aging, where efficiency initially increases during storage (positive aging) but is entirely lost upon extended aging (negative aging), hinders further device development. It uncovered that it chemical changes to nanocrystal (NC)-based electron transport layer (ETL) give rise positive their drift in structure and morphology leading transiently improved...
Abstract InSb colloidal quantum dots (CQDs) hold promise in short‐wave infrared sensing; however, their synthesis presents ongoing challenges, particularly achieving precise size control – this is the result of poorly controlled reactivity among precursors. Herein, use alkyl‐phosphine and amine‐based organic additives to In Sb precursors during nucleation growth CQDs developed. This interplay between additive enables having narrowed distributions; bandgaps tunable across 1.2–1.5 µm spectral...
Abstract Lead‐free III‐V colloidal quantum dots (CQDs) are of significant interest for their potential in near‐infrared (NIR) to short‐wave infrared (SWIR) photodetection. However, achieving effective surface passivation remains challenging, especially as larger CQD sizes introduce more complex facets and compositions while shifting the absorption peak from NIR SWIR range. In this study, a mixed‐halide strategy is developed large InAs CQDs, an approach that led doubling anti‐oxidation...
Exciton exchange between semiconductor quantum dots (QDs) and organic chromophores may find application in next-generation photovoltaics, probes, or photocatalysts. We study the effect of shell composition thickness on triplet energy transfer (TET) from PbS QDs to rubrene a hybrid organic–inorganic photon upconverison system show that defect states introduced by surface adsorbed Zn Cd result up 700 325 fold enhancements yield (QY). Time-correlated single-photon counting, photoluminescence...
Emotion recognition is receiving significant attention in research on health care and Human-Computer Interaction (HCI). Due to the high correlation with emotion capability affect deceptive external expressions such as voices faces, Electroencephalogram (EEG) based methods have been globally accepted widely applied. Recently, great improvements made development of machine learning for EEG-based detection. However, there are still some major disadvantages previous studies. Firstly, traditional...
Lead-free double perovskites offer non-toxic properties and strong emission via alloying doping. Herein, we report the synthesis of Bi-doped pure Rb2HfCl6 Cs-alloyed RbCsHfCl6 microcrystals. The microcrystals are nearly non-emissive while with Cs Bi doping lead to deep blue at 466 nm an increase in photoluminescence quantum yield from ∼0 66%. Density functional theory studies attest improved phase stability due Cs-alloying link Bi3+ dopant-induced localized states.
Heavy-metal-free III–V colloidal quantum dots (CQDs) show promise in optoelectronics: Recent advancements the synthesis of large-diameter indium arsenide (InAs) CQDs provide access to short-wave infrared (IR) wavelengths for three-dimensional ranging and imaging. In early studies, however, we were unable achieve a rectifying photodiode using molybdenum oxide/polymer hole transport layers, as shallow valence bandedge (5.0 eV) was misaligned with ionization potentials widely used layers. This...
Triplet energy transfer (TET) from semiconductor nanocrystals (NCs) to molecules is one of the bottlenecks that limits efficiency photon upconversion. While an inorganic shell can enhance photoluminescence quantum yields (PLQYs), role with respect TET still not clear. In this work, CdS and ZnS shells different thickness are grown on 2.9 nm diameter CdSe NCs, resulting in nanostructures here have increased radiative rates compared core. these NCs bound 9-anthracene carboxylic acid...