Colloidal Alloyed Quantum Dots with Enhanced Photoluminescence Quantum Yield in the NIR-II Window

Abstract

Semiconductor quantum dots (QDs) with photoluminescence (PL) emission at 900−1700 nm (denoted as the second near-infrared window, NIR-II) exhibit much-depressed photon absorption and scattering, which has stimulated extensive researches in biomedical imaging and NIR devices. However, it is very challenging to develop NIR-II QDs with a high photoluminescence quantum yield (PLQY) and excellent biocompatibility. Herein, we designed and synthesized an alloyed silver gold selenide (AgAuSe) QD with a bright emission from 820 to 1170 nm and achieved a record absolute PLQY of 65.3% at 978 nm emission among NIR-II QDs without a toxic element and a long lifetime of 4.58 μs. It is proved that the high PLQY and long lifetime are mainly attributed to the prevented nonradiative transition of excitons, probably resulted from suppressing cation vacancies and crystal defects from the high mobility of Ag ions by alloying Au atoms. These high-PLQY QDs with nontoxic heavy metal exhibit great application potential in bioimaging, light emitting diodes (LEDs), and photovoltaic devices.

Near infrared bioimaging and biosensing with semiconductor and rare-earth nanoparticles: recent developments in multifunctional nanomaterials

“…This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Despite great progress in the use of Ag-based SNCs in biomedical research, 73 82 And most recently, the Au-doped Ag 2 Te SNCs, have been applied to study and diagnose ischemia. 83 Thus, the progress made on the use of Ag-based SNCs in multivariate diagnostics and theranostics, complemented with the improvement in the brightness of these View Article Online nanocrystals, distinguishes these materials as potent candidates for further biomedical exploration.…”

“…76 The presence of Cu + in Ag 81 However, without falling back onto using toxic heavy metals, H. Yang, have made alloyed AgAuSe SNCs with emission tunable in the 820-1170 nm range and PLQY up to 65.3 %. 82 And most recently, the Au-doped Ag 2 Te SNCs, have been applied to study and diagnose ischemia. 83 Thus, the progress made on the use of Ag-based SNCs in multivariate diagnostics and theranostics, complemented with the improvement in the brightness of these nanocrystals, distinguishes these materials as potent candidates for further biomedical exploration.…”

Near-Infrared Inorganic Nanomaterials for Precise Diagnosis and Therapy

“…Reproduced with permission from . wavelength and band gap energy of QDs can be tuned by regulating their size, materials et al (Hanson et al, 2017;Grimaldi et al, 2019;Santos et al, 2020;Sarkar et al, 2020;Yang et al, 2021). It is possible to achieve QDs with NIR light emission by selectively control the composition process, endowing QDs superior imaging capability (Hong et al, 2017;Cao et al, 2019;Sonego et al, 2019;Gil et al, 2021).…”

“…When the excited electron resumes its ground state, it eliminates the exciton and release energy in the shape of a photon through radiative recombination ( Figures 3A,B ). In the quantum confinement system, the emission wavelength and band gap energy of QDs can be tuned by regulating their size, materials et al ( Hanson et al, 2017 ; Grimaldi et al, 2019 ; Santos et al, 2020 ; Sarkar et al, 2020 ; Yang et al, 2021 ). It is possible to achieve QDs with NIR light emission by selectively control the composition process, endowing QDs superior imaging capability ( Hong et al, 2017 ; Cao et al, 2019 ; Sonego et al, 2019 ; Gil et al, 2021 ).…”

Au‐Doped Ag2Te Quantum Dots with Bright NIR‐IIb Fluorescence for In Situ Monitoring of Angiogenesis and Arteriogenesis in a Hindlimb Ischemic Model

“…However, the low photoluminescence quantum yield (PLQY) and stability of Ag 2 Te prevent its practices, which could be attributed to the cation vacancies and crystal defects resulted from the high mobility of Ag ion. Recently, we first utilized cation exchange method to obtain Pb:Ag 2 Se QDs [ 30 ] and AgAuSe alloyed QDs [ 31 ] from Ag 2 Se QDs, both of which presented enhanced PL emission in NIR‐II window by preventing the nonradiative transition of excitons. Therefore, we speculate that this new cation exchange strategy might be a feasible way to improve the PL of Ag 2 Te in the NIR‐IIb window for ultrahigh spatial resolution imaging.…”