ACS Applied Nano Materials
·
2023
·
IF 5.9
Hao Hao,Hui-Ling Hu,Yi Liu,Feng-Lei Jiang
In this work, CdSe/ZnS core/shell quantum dots (QDs) were synthesized. Dilution of the as-synthesized QDs would lead to instability with photoluminescence (PL) quenching. It was found that the addition of tertiary phosphine and alkylthiol could recover the PL intensity of diluted QDs and make these QDs stable. Specifically, the recovery efficiency of tertiary phosphine was stronger than that of alkylthiol. Trioctylphosphine (TOP) and octanethiol (OT) were chosen as the representative ligands, respectively. Isothermal titration calorimetry (ITC) demonstrated that interactions between both TOP/OT and QDs were exothermic and spontaneous. The interaction between TOP and QDs was mainly driven by van der Waals forces due to the branched structure. This interaction had a negative entropy change, while the interaction between OT and QDs had a positive entropy change. There were about ∼12 TOP molecules and ∼17 OT molecules bound to a QD particle. The binding constants of TOP/OT to QDs were 1.6 × 103 and 12.8 × 103 M–1, respectively. The reaction rate between TOP and QDs was fast, and the addition of OT could slow the reaction rate constant from 0.081 to 0.024 min–1. PL decay indicated that TOP and OT could increase the radiative recombination of excitons. Furthermore, both TOP and OT could greatly improve the brightness of the QD films, which was a prerequisite for the efficient improvement of quantum dot light-emitting diodes. This work explicitly investigated the dilution process of QDs, explored the methods for keeping diluted QDs stable and bright, and highlighted the importance of surface ligands.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2024
·
IF 5.3
Rongrong Hu,Wenfang Peng,Lin Cheng,Qiaoyun Wu,Gaolei Dong,Pan Liang,Bobo Yang,Yuefeng Li,Jun Zou,Donghai Feng
Metal halide perovskite nanocrystals (NCs) are emerging for emitting applications due to their high photoluminescence (PL) quantum yield and wide PL wavelength tunability. Here, the light-induced PL enhancement in complexes of CsPbBr3 NCs and 1-octanethiol (OT) molecules (refers to below as NC–OT complexes) is investigated. In comparison with that of as-grown CsPbBr3 NCs, the PL intensity of NC–OT complexes is lower before light illumination. While after ultraviolet light illumination, the PL performance of NC–OT complexes is improved in both air and nitrogen atmospheres. Compared with air atmospheres, anaerobic atmospheres are more effective at increasing the PL intensity because of eliminating photo-oxidation. The light illumination prevents the nonradiative process and enhances the radiative emission in NC–OT complexes, supported by transient PL and photobleaching measurements, due to better surface passivation through thiol–ene reactions. The light-induced PL enhancement in NC–OT complexes provides valuable information for the applications of perovskite nanomaterial-based emitting devices.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Nisar Hussain,Hongbin Pu,Abid Hussain,Da-Wen Sun
Existing approaches for the screening of unsafe materials in food matrices are time-consuming, tiresome and destructive in nature. Therefore, in the current study, a surface-enhanced Raman spectroscopy (SERS) method based on octanethiol-functionalized core-shell nanoparticles (Oct/Au@AgNPs) was established for rapid detection of ziram in apple and pear fruits. The morphology of substrate was evaluated using high-resolution TEM images and superimposed HAADF-STEM-EDS elemental mapping images, which confirmed that Au@AgNPs having gold (Au) core size of 28 nm in diameter and silver (Ag) shell of 5.5 nm in thickness were successfully grafted with octanethiol. The SERS method with the sensitive nanoparticles could detect ziram of up to 0.015 and 0.016 ppm in apple and pear with high coefficients of determination (R 2 ) of 0.9987 and 0.9993, respectively. Furthermore, satisfactory recoveries (80–106%) were also accomplished for the fungicide in real samples. This work demonstrated that the functionalized silver-coated gold nanoparticles were easy to prepare and could be used as sensitive SERS platforms for monitoring of other agrochemicals in foods.
研究领域:
分析化学
·
食品科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry Letters
·
2023
·
IF 5.7
Fei Li,Jiao Jiao Liu,Qiulei Xu,Ruiguang Chang,Lei Wang,Zhenghui Wu,Huaibin Shen,Zuliang Du
PbS quantum dot light-emitting diodes (QLEDs) emitting around 1550 nm promise important applications in optical communications. However, due to insufficient suppression of surface traps for large-size PbS quantum dots (QDs), their performance under large driving current density was not satisfactory. In this work, octanethiol surfactant was added into a PbS QD solution and adsorbed onto the dot surface. As a result, the surface traps and the continuous oxidation of the unprotected (100) facets in PbS QDs were greatly suppressed. Therefore, the PbS QDs with octanethiol doubled their photoluminescence efficiency and showed outstanding stability. The PbS-based QLEDs with benchmark device structure showed a breakthrough high radiance of 18.3 W sr–1 m–2 with >2000 mA/cm2 driving current density. The efficient passivation of surface traps with octanethiol surfactant and the suppressed coupling between excitons and surface states under large working current were the main reasons for achieving the breakthrough high radiance.
研究领域:
纳米技术
·
光电子学
·
材料科学
·
半导体器件
·
量子点
✓ 已验证
DOI
高影响因子
POLYMER INTERNATIONAL
·
2011
·Vol. 60
·期 4
·703-710
·
IF 2.056
Zhihong Zhang,Yan Liang,Ping Liang,Chao Li,Shaoming Fang
In order to fabricate a new polymer matrix for application in biochips and to understand the mechanism of adsorption of proteins on conducting polymers, we prepared polypyrrole (PPy) functionalized with ω-( N -pyrrolyl)-octylthiol moieties. The chemical structure of the polymer could be controlled by varying the concentration of pyrrole added as the monomer. Initially, ω-( N -pyrrolyl)-octylthiol was self-assembled into a monolayer on a gold surface. Thereafter, a layer of uniform and smooth PPy was obtained by the chemical copolymerization of pyrrole and the ω-( N -pyrrolyl)-octylthiol. Bovine serum albumin (BSA) adsorption on the polymer was investigated using surface plasmon resonance spectroscopy and cyclic voltammograms. The chemical structure and monomer components of the as-prepared films were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Water contact angle measurements were used to assess the surface wettability of the films throughout the preparative procedure. The kinetics of BSA adsorption onto the polymer could be controlled by varying the copolymer thickness and the pH value of the buffer solutions used. Moreover, the electroactivity was changed upon BSA binding. The results suggest that the new conducting polymer may potentially be applied as a more sensitive and reliable matrix in protein sensors. Copyright © 2011 Society of Chemical Industry
研究领域:
材料科学
·
生物技术
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
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