Imperial College London

Peter Haynes

Faculty of EngineeringDepartment of Materials

Head of Department of Materials
 
 
 
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Contact

 

+44 (0)20 7594 5158p.haynes Website CV

 
 
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Assistant

 

Miss Catherine Graham +44 (0)20 7594 3330

 
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Location

 

201BRoyal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Corsini:2017:10.1021/acs.nanolett.6b04461,
author = {Corsini, NRC and Hine, NDM and Haynes, PD and Molteni, C},
doi = {10.1021/acs.nanolett.6b04461},
journal = {Nano Letters},
pages = {1042--1048},
title = {Unravelling the roles of size, ligands and pressure in the piezochromic properties of CdS nanocrystals},
url = {http://dx.doi.org/10.1021/acs.nanolett.6b04461},
volume = {17},
year = {2017}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - Understanding the effects of pressure-induceddeformations on the optoelectronic propertiesof nanomaterials is important not only fromthe fundamental point of view, but also for po-tential applications such as stress sensors andelectromechanical devices. Here we describethe novel insights into these piezochromic ef-fects gained from using a linear-scaling den-sity functional theory framework and an elec-tronic enthalpy scheme, which allow us to ac-curately characterize the electronic structure ofCdS nanocrystals with a zincblende-like coreof experimentally relevant size. In particu-lar we focus on unravelling the complex inter-play of size and surface (phenyl) ligands withpressure. We show that pressure-induced de-formations are not simple isotropic scaling ofthe original structures and that the change inHOMO-LUMO gap with pressure results fromtwo competing factors: (i) a bulk-like linear in-crease due to compression, which is offset by(ii) distortions/disorder and, to a lesser ex-tent, orbital hybridization induced by ligandsaffecting the frontier orbitals. Moreover, weobserve that the main peak in the optical ab-sorption spectra is systematically red-shifted orblue-shifted, as pressure is increased up to 5GPa, depending on the presence or absenceof phenyl ligands. These heavily hybridize thefrontier orbitals, causing a reduction in over-lap and oscillator strength, so that at zero pres-sure the lowest energy transition involves deeperhole orbitals than in the case of hydrogen-capped nanocrystals; the application of pressureinduces greater delocalisation over the wholenanocrystals bringing the frontier hole orbitalsinto play and resulting in an unexpected redshift for the phenyl-capped nanocrystals, in partcaused by distortions. In response to a growinginterest in relatively small nanocrystals that canbe difficult to accurately characterize with ex-perimental techniques, this work exemplifies thedetailed understanding of structure-property re-lationships under p
AU - Corsini,NRC
AU - Hine,NDM
AU - Haynes,PD
AU - Molteni,C
DO - 10.1021/acs.nanolett.6b04461
EP - 1048
PY - 2017///
SN - 1530-6992
SP - 1042
TI - Unravelling the roles of size, ligands and pressure in the piezochromic properties of CdS nanocrystals
T2 - Nano Letters
UR - http://dx.doi.org/10.1021/acs.nanolett.6b04461
UR - http://hdl.handle.net/10044/1/44203
VL - 17
ER -