We present surface hopping simulations of the photodynamics of self-assembled monolayers (SAMs) of 4′-(biphenyl-4-ylazo)-biphenyl-4-thiol (ABPT) on Au(111). We show that trans → cis photoisomerization is suppressed because of steric hindrance in a well-ordered SAM. Photoisomerization is instead viable in the presence of defects. Two particularly important defects are the boundaries between domains of trans-ABPT molecules leaning in different directions (a line defect) and single cis molecules embedded in a SAM of trans (a point defect). Our findings explain the cooperative behavior observed during the photoisomerization of a trans-ABPT SAM, leading to large domains of pure cis and trans isomers. The line and point defects are predicted to produce different patterns of cis-ABPT molecules during the early stages of the photoconversion.

Photoisomerization of Self-Assembled Monolayers of Azobiphenyls: Simulations Highlight the Role of Packing and Defects

CANTATORE, VALENTINA;GRANUCCI, GIOVANNI
;
PERSICO, MAURIZIO
2016

Abstract

We present surface hopping simulations of the photodynamics of self-assembled monolayers (SAMs) of 4′-(biphenyl-4-ylazo)-biphenyl-4-thiol (ABPT) on Au(111). We show that trans → cis photoisomerization is suppressed because of steric hindrance in a well-ordered SAM. Photoisomerization is instead viable in the presence of defects. Two particularly important defects are the boundaries between domains of trans-ABPT molecules leaning in different directions (a line defect) and single cis molecules embedded in a SAM of trans (a point defect). Our findings explain the cooperative behavior observed during the photoisomerization of a trans-ABPT SAM, leading to large domains of pure cis and trans isomers. The line and point defects are predicted to produce different patterns of cis-ABPT molecules during the early stages of the photoconversion.
Cantatore, Valentina; Granucci, Giovanni; Rousseau, Guillaume; Padula, Giancarlo; Persico, Maurizio
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/826106
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