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. 2024-01-20T01:32:21Z 2024-01-20T01:32:21Z 2021-09-01 2017-05-05 0957-4484 https://pubs.kist.re.kr/handle/201004/122750 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. English IOP PUBLISHING LTD LIGHT-EMITTING-DIODES REVERSE MICROEMULSION METHOD NANOCRYSTAL QUANTUM DOTS SUPPRESSED BLINKING CDSE NANOCRYSTALS IN-SITU SHELL SURFACE SPHERES EMISSION Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability Article 10.1088/1361-6528/aa6828 1 NANOTECHNOLOGY, v.28, no.18 NANOTECHNOLOGY 28 18 scie scopus 000399273900001 2-s2.0-85017425102 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Science & Technology - Other Topics Materials Science Physics Article LIGHT-EMITTING-DIODES REVERSE MICROEMULSION METHOD NANOCRYSTAL QUANTUM DOTS SUPPRESSED BLINKING CDSE NANOCRYSTALS IN-SITU SHELL SURFACE SPHERES EMISSION quantum dots silica coating reverse microemulsion stability core/shell