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Bandgap Tuning with Thermal Residual Stresses Induced in a Quantum Dot
Author(s) -
Kong EuiHyun,
Joo SooHyun,
Park HyunJin,
Song Seungwoo,
Chang YongJune,
Kim Hyoung Seop,
Jang Hyun Myung
Publication year - 2014
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201400392
Subject(s) - quantum dot , materials science , band gap , residual stress , residual , optoelectronics , distortion (music) , thermal , lattice (music) , thermal expansion , nanotechnology , composite material , physics , computer science , thermodynamics , cmos , amplifier , algorithm , acoustics
Lattice distortion induced by residual stresses can alter electronic and mechanical properties of materials significantly. Herein, a novel way of the bandgap tuning in a quantum dot (QD) by lattice distortion is presented using 4‐nm‐sized CdS QDs grown on a TiO 2 particle as an application example. The bandgap tuning (from 2.74 eV to 2.49 eV) of a CdS QD is achieved by suitably adjusting the degree of lattice distortion in a QD via the tensile residual stresses which arise from the difference in thermal expansion coefficients between CdS and TiO 2 . The idea of bandgap tuning is then applied to QD‐sensitized solar cells, achieving ≈60% increase in the power conversion efficiency by controlling the degree of thermal residual stress. Since the present methodology is not limited to a specific QD system, it will potentially pave a way to unexplored quantum effects in various QD‐based applications.