Anomalous photoluminescence in CdSe quantum dot solids at high pressure due to nonuniform stress

PHYS 454

Christian D. Grant, grant29@llnl.gov1, Jonathan C. Crowhurst1, Sebastien Hamel2, Natalia Zaitseva2, and Andrew Williamson3. (1) CMELS, Chemical Sciences Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, (2) Physics and Applied Technology, H-Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, (3) Physic Ventures, 200 California Street, San Francisco, CA 94111
The application of static high pressure provides a means to precisely control and investigate many fundamental and unique nanoparticle properties. CdSe is a model quantum dot system whose behavior under high pressure has been extensively studied; however, the effect of non-uniform stresses on this system has not been fully appreciated. We present photoluminescence data obtained from CdSe quantum dot solids in different stress environments varying from purely uniform to highly non-uniform. Small deviations from a uniform stress distribution profoundly affect the electronic properties of this system. In non-uniform stress environments, we observe a pronounced photoluminescence energy flattening above 3 GPa. We validate our observations with theoretical calculations obtained using an all-atom semiempirical pseudopotential technique. The importance of this effect must be considered when investigating other potentially pressure mediated phenomena.
 

PHYS Poster Session - Nanostructured Materials and Nanophotonics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008