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Crafting Core/Graded Shell–Shell Quantum Dots with Suppressed Re‐absorption and Tunable Stokes Shift as High Optical Gain Materials
Author(s) -
Jung Jaehan,
Lin Chun Hao,
Yoon Young Jun,
Malak Sidney T.,
Zhai Yaxin,
Thomas Edwin L.,
Vardeny Valy,
Tsukruk Vladimir V.,
Lin Zhiqun
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201601198
Subject(s) - stokes shift , quantum dot , auger effect , absorption (acoustics) , optoelectronics , materials science , laser , chemistry , auger , atomic physics , optics , physics , luminescence , composite material
The key to utilizing quantum dots (QDs) as lasing media is to effectively reduce non‐radiative processes, such as Auger recombination and surface trapping. A robust strategy to craft a set of CdSe/Cd 1− x Zn x Se 1− y S y /ZnS core/graded shell–shell QDs with suppressed re‐absorption, reduced Auger recombination rate, and tunable Stokes shift is presented. In sharp contrast to conventional CdSe/ZnS QDs, which have a large energy level mismatch between CdSe and ZnS and thus show strong re‐absorption and a constrained Stokes shift, the as‐synthesized CdSe/Cd 1− x Zn x Se 1− y S y /ZnS QDs exhibited the suppressed re‐absorption of CdSe core and tunable Stokes shift as a direct consequence of the delocalization of the electron wavefunction over the entire QD. Such Stokes shift‐engineered QDs with suppressed re‐absorption may represent an important class of building blocks for use in lasers, light emitting diodes, solar concentrators, and parity‐time symmetry materials and devices.