Anomalous Photoluminescence in CdSe Quantum‐Dot Solids at High Pressure Due to Nonuniform Stress

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Abstract
The application of static high pressure provides a means to precisely control and investigate many fundamental and unique properties of nanoparticles. CdSe is a model quantum‐dot system, the behavior of which under high pressure has been extensively studied; however, the effect of nonuniform stresses on this system has not been fully appreciated. Photoluminescence data obtained from CdSe quantum‐dot solids in different stress environments varying from purely uniform to highly nonuniform are presented. Small deviations from a uniform stress distribution profoundly affect the electronic properties of this system. In nonuniform stress environments, a pronounced flattening of the photoluminescence enegy is observed above 3 GPa. The observations are validated with theoretical calculations obtained using an all‐atom semiempirical pseudopotential technique. This effect must be considered when investigating other potentially pressure‐mediated phenomena.