Controlling Nonlinear Optical Switch of Diarylethene by Changing Sizes of Fullerene: A Theoretical Study

Abstract

AbstractFullerene is a material with good electrical conductivity and thermal stability, and its size is an important factor to influence its photoelectric property. In this work, effect of fullerene size (C20, C60, and C70) on nonlinear optical (NLO) switchable molecule diarylethene (DAE) was explored. In the aspect of molecular NLO properties, it could be found that the static first hyperpolarizability βtot of Cx‐O (x=20, 60, 70) was larger than that of Cx‐C (x=20, 60, 70), and the βtot difference between open‐ring and closed‐ring structure increased from 19 to 1431 au with the size of fullerene increased. Especially for C70‐DAE, its largest contrast of βtot values between open‐ring and closed‐ring structure suggested its superiority among three groups of NLO switchable complexes. The result could attribute to C70‐O exhibits a strong dipole characteristic, whereas C70‐C displays a weak dipole characteristic. By analyzing dynamic first hyperpolarizability, it could be found large NLO response mainly depended on molecular dipole characteristics. As a result, for C70‐DAE, βHRS of open‐ring structure was still larger than that of closed‐ring structure. However, the dynamic first hyperpolarizability βHRS of open‐ring structure was smaller than that of closed‐ring structure in both C20‐DAE and C60‐DAE. The switching efficiency was reversed.