The Structural Transition Behavior of CdSe/ZnS Core/shell Quantum Dots under High Pressure

Journal Article · Sat Dec 31 04:00:00 EST 2011 · Physica Status Solidi B

DOI:https://doi.org/10.1002/pssb.201000802· OSTI ID:1042061

Li, Z; Wang, L; Liu, B; Wang, J; Liu, B; Li, Q; Zou, B; Cui, T; Meng, Y; Mao, H

The structural phase transition of CdSe/ZnS core/shell quantum dots (QDs) has been studied by in situ angle-dispersive X-ray diffraction under high pressure up to 53.6?GPa. The CdSe core transforms from wurtzite to rock-salt structure near 6.3?GPa and then to Cmcm or distorted Cmcm structure probably occurs at 45.1?GPa which has not been observed in CdSe nanomaterials before. The critical pressure from wurtzite to rock-salt and the bulk modulus of rock-salt phase are much higher than those for bulky and uncapped nanoparticle CdSe. The released sample can be kept in rock-salt phase for a certain time, verified by photoluminescence (PL) spectra, quite different from the reversible transition for pure CdSe. A reasonable interpretation of the experimental phenomena is given by comparing the bulk modulus of the core and shell and studying the stress sate of the core after decompression. Our study suggests that capping a hard shell is an effective approach to quench the high pressure phase of nanomaterial with a reversible phase transition.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1042061
• Report Number(s): BNL--97739-2012-JA
• Journal Information: Physica Status Solidi B, Journal Name: Physica Status Solidi B Journal Issue: 5 Vol. 248; ISSN 0370-1972
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
CRITICAL PRESSURE
PHOTOLUMINESCENCE
QUANTUM DOTS
SALT DEPOSITS
SPECTRA
X-RAY DIFFRACTION