Probing photoluminescence dynamics of colloidal CdSe/ZnS core/shell nanoparticles

Kaur, Gurvir; Tripathi, S. K.

doi:10.1016/j.jlumin.2014.06.052

Cited by 25 publications

(6 citation statements)

References 39 publications

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“…The radiative recombination produces photons, and the non-radiative recombination caused by defect states (DS) produces phonons. These two processes reveal the photoluminescence and quenching mechanism of QDs [37].…”

Section: Samplesmentioning

confidence: 92%

Enhancing oxygen/moisture resistance of quantum dots by short-chain, densely cross-linked silica glass network

Ye¹,

Zhou²,

Zhang³

et al. 2022

Nanotechnology

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Quantum dots (QDs) are facing significant photoluminescence degradation in moisture environment. In QDs-silicone composites, the poor water resistance of silicone matrix makes it easy for water and oxygen molecules to erode QDs. To tackle this issue, we proposed a new QDs protection strategy by introducing short-chain silica precursors onto the QDs’ surface, so that a dense silica passivation layer could be formed onto the QDs nanoparticles. Sol-gel method based on 3-aminopropyl triethoxysilane (APTES), 3-mercaptopropyl trimethoxysilane (MPTMS), and 3-mercaptopropyl triethoxysilane (MPTES) were adopted to prepare the uniform and crack-free QDs-silica glass (QD-glass). Because of the crosslinking of short-chain precursors, the formed silica glass possesses 38.6% smaller pore width and 68.6% lower pore volume than silicone, indicating its denser cross-linked network surrounding QDs. After 360-hour water immersion, the QDs-glass demonstrated a 6% enhancement in red-light peak intensity, and maintained a stable full width at half maximum (FWHM) and peak wavelength, proving its excellent water-resistant ability. However, the conventional QDs-silicone composites not only showed a decrease of 75.3% in red-light peak intensity, but also a broadened FWHM and a redshifted peak wavelength after water immersion. QDs-glass also showed superior photostability after 132-hour exposure to blue light. Red-light peak intensity of QDs-glass remained 87.3% of the initial while that of QDs-silicone decreased to 19.8%. And the intensity of QDs-glass dropped to 62.3% of that under 20 ℃ after thermal treatment of 160 ℃. Besides, under increasing driving currents, the light conversion efficiency (LCE) drop of QDs-glass is only one fifth that of QDs-silicone. Based on the QDs-glass, the white light-emitting diodes was achieved with a high luminous efficiency (LE) of 126.5 lm/W and a high color rendering index (CRI) of 95.4. Thus, the newly proposed QD-glass has great significance in guaranteeing the working reliability of QDs-converted devices against moisture and high-power environment.

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Section: Samplesmentioning

confidence: 92%

Enhancing oxygen/moisture resistance of quantum dots by short-chain, densely cross-linked silica glass network

Ye¹,

Zhou²,

Zhang³

et al. 2022

Nanotechnology

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show abstract

“…The shortest lifetime is observed for undoped ternary QDs with s 1 ¼ 8.9 ns attributed to the band edge emission of excitons, while s 2 ¼ 921.6 and s 3 ¼ 140.4 ns correspond to deep trap emission associated with surface defects and dark exciton states in QDs, respectively. 49,50 The longest lifetime is observed for the dopant Cu (10%) with an average lifetime of 2394.5 ns. The change in the lifetime ternary QDs aer the incorporation of the Cu dopant (1-10%) increases from 5 to 22 times as compared to undoped ternary QDs.…”

Section: Effect Of Dopant Concentrationmentioning

confidence: 99%

Influence of precursor ratio and dopant concentration on the structure and optical properties of Cu-doped ZnCdSe-alloyed quantum dots

Ca¹,

Van

et al. 2020

RSC Adv.

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“…Ternary I-III-VI QDs synthesised as core QDs show low quantum yield and surface defects [32,33]. This occurs due to their high surface to volume ratio as a result of their small size.…”

Section: Ternary Qds Core/shell Systemmentioning

confidence: 99%

Synthesis strategies and application of ternary quantum dots — in cancer therapy

Aladesuyi

Oluwafemi

2020

Nano-Structures & Nano-Objects

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Semiconductor nanoparticles also known as quantum dots (QDs) have continued to receive more attention from researchers due to their unique optical, magnetic and photo physical properties which made them useful as biomedical materials, solar cells, catalyst etc. However, ternary I-III-VI QDs have shown to be a safer alternative to the binary II-VI or IV-VI QDs due to the absent of heavy toxic elements such as Cd and Pb. Cancer management and therapy in Africa has been bedevilled by a lot of challenges such as inaccurate diagnosis and ineffective therapeutic methods. Therefore, the need to develop an appropriate approach for cancer detection and treatment is of paramount importance. Tunable optical properties and absorption in the near infra-red region of the ternary QDs makes them useful as fluorescent probes in cancer detection and treatment. They have the ability to detect specific cancer cells including those that are not easily detected by modern imaging technique. Also, properties such as non-bleaching, stability, water solubility etc. made them a desirable fluorophore when compared to conventional dyes. Most cancer drugs suffer from inherent shortcomings such as limited absorption, insolubility and aggregation. However, these shortcomings can be overcome when these drugs are applied in form of conjugated systems. The use of QDs as conjugates has revolutionise the treatment of cancer in the 21st century. This review provides information about the synthesis strategies, optical properties, hydrophilization and bioconjugation of ternary I-III-VI QDs. Furthermore, we described the various biomedical applications in biosensors, bioimaging, drug delivery and phototherapeutic techniques. Finally, we looked at the challenges and future perspective of these QDs in cancer management.

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Probing photoluminescence dynamics of colloidal CdSe/ZnS core/shell nanoparticles

Cited by 25 publications

References 39 publications

Enhancing oxygen/moisture resistance of quantum dots by short-chain, densely cross-linked silica glass network

Enhancing oxygen/moisture resistance of quantum dots by short-chain, densely cross-linked silica glass network

Influence of precursor ratio and dopant concentration on the structure and optical properties of Cu-doped ZnCdSe-alloyed quantum dots

Synthesis strategies and application of ternary quantum dots — in cancer therapy

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