Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability

Nianfang Wang, Sungjun Koh, Byeong Guk Jeong, Dongkyu Lee, Whi Dong Kim, Kyoungwon Park, Min Ki Nam, Kangha Lee, Yewon Kim, Baek Hee Lee, Kangtaek Lee, Wan Ki Bae, Doh C. Lee

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We present facile synthesis of bright CdS/CdSe/CdS@SiO2 nanoparticles with 72% of quantum yields (QYs) retaining ca 80% of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO2 is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO2 shows the lowest retaining ratio (36%) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO2 and SQW/SiO2 is over 80% and SQW/SiO2 shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO2-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO2 nanoparticles in bio-labeling or display applications.

Original languageEnglish
Article number185603
JournalNanotechnology
Volume28
Issue number18
DOIs
Publication statusPublished - 2017 Apr 10

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Quantum yield
Silicon Dioxide
Thermodynamic stability
Semiconductor quantum wells
Silica
Nanoparticles
Semiconductor quantum dots
Photoluminescence
Encapsulation
Seed
Surface defects
Microemulsions
Passivation
Excitons
Labeling
Luminescence
Etching
Display devices
Annealing
Semiconductor materials

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

Cite this

Wang, Nianfang ; Koh, Sungjun ; Jeong, Byeong Guk ; Lee, Dongkyu ; Kim, Whi Dong ; Park, Kyoungwon ; Nam, Min Ki ; Lee, Kangha ; Kim, Yewon ; Lee, Baek Hee ; Lee, Kangtaek ; Bae, Wan Ki ; Lee, Doh C. / Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability. In: Nanotechnology. 2017 ; Vol. 28, No. 18.
@article{bc50eaea01274c0780a47c5079bf8077,
title = "Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability",
abstract = "We present facile synthesis of bright CdS/CdSe/CdS@SiO2 nanoparticles with 72{\%} of quantum yields (QYs) retaining ca 80{\%} of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO2 is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO2 shows the lowest retaining ratio (36{\%}) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO2 and SQW/SiO2 is over 80{\%} and SQW/SiO2 shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO2-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO2 nanoparticles in bio-labeling or display applications.",
author = "Nianfang Wang and Sungjun Koh and Jeong, {Byeong Guk} and Dongkyu Lee and Kim, {Whi Dong} and Kyoungwon Park and Nam, {Min Ki} and Kangha Lee and Yewon Kim and Lee, {Baek Hee} and Kangtaek Lee and Bae, {Wan Ki} and Lee, {Doh C.}",
year = "2017",
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Wang, N, Koh, S, Jeong, BG, Lee, D, Kim, WD, Park, K, Nam, MK, Lee, K, Kim, Y, Lee, BH, Lee, K, Bae, WK & Lee, DC 2017, 'Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability', Nanotechnology, vol. 28, no. 18, 185603. https://doi.org/10.1088/1361-6528/aa6828

Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability. / Wang, Nianfang; Koh, Sungjun; Jeong, Byeong Guk; Lee, Dongkyu; Kim, Whi Dong; Park, Kyoungwon; Nam, Min Ki; Lee, Kangha; Kim, Yewon; Lee, Baek Hee; Lee, Kangtaek; Bae, Wan Ki; Lee, Doh C.

In: Nanotechnology, Vol. 28, No. 18, 185603, 10.04.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability

AU - Wang, Nianfang

AU - Koh, Sungjun

AU - Jeong, Byeong Guk

AU - Lee, Dongkyu

AU - Kim, Whi Dong

AU - Park, Kyoungwon

AU - Nam, Min Ki

AU - Lee, Kangha

AU - Kim, Yewon

AU - Lee, Baek Hee

AU - Lee, Kangtaek

AU - Bae, Wan Ki

AU - Lee, Doh C.

PY - 2017/4/10

Y1 - 2017/4/10

N2 - We present facile synthesis of bright CdS/CdSe/CdS@SiO2 nanoparticles with 72% of quantum yields (QYs) retaining ca 80% of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO2 is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO2 shows the lowest retaining ratio (36%) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO2 and SQW/SiO2 is over 80% and SQW/SiO2 shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO2-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO2 nanoparticles in bio-labeling or display applications.

AB - We present facile synthesis of bright CdS/CdSe/CdS@SiO2 nanoparticles with 72% of quantum yields (QYs) retaining ca 80% of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO2 is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO2 shows the lowest retaining ratio (36%) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO2 and SQW/SiO2 is over 80% and SQW/SiO2 shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO2-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO2 nanoparticles in bio-labeling or display applications.

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U2 - 10.1088/1361-6528/aa6828

DO - 10.1088/1361-6528/aa6828

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VL - 28

JO - Nanotechnology

JF - Nanotechnology

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