A building-block design for enhanced visible-light switching of diarylethenes

Zhiwei Zhang,Peipei Jin,Jiadan Xue,Lu Sun,Jinhai Huang,Junji Zhang,He Tian,Wenhui Wang

doi:10.1038/s41467-019-12302-6

Abstract

Current development of light-responsive materials and technologies imposes an urgent demand on visible-light photoswitching on account of its mild excitation with high penetration ability and low photo-toxicity. However, complicated molecular design and laborious synthesis are often required for visible-light photoswitch, especially for diarylethenes. Worse still, a dilemma is encountered as the visible-light excitation of the diarylethene is often achieved at the expense of photochromic performances. To tackle these setbacks, we introduce a building-block design strategy to achieve all-visible-light photochromism with the triplet-sensitization mechanism. The simply designed diarylethene system is constructed by employing a sensitizer building-block with narrow singlet-triplet energy gap (ΔEST) to a diarylethene building-block. A significant improvement on the photochromic efficiency is obtained as well as an enhanced photo-fatigue resistance over those under UV irradiation. The balance between the visible-light excitation and decent photochromism is thus realized, promoting a guiding principle for the visible-light photochromism.

Highlights

Current development of light-responsive materials and technologies imposes an urgent demand on visible-light photoswitching on account of its mild excitation with high penetration ability and low photo-toxicity
One well-studied category is based on the metal-to-ligand chargetransfer (MLCT) mechanism[24,25,26,27], as a transition metal complex is introduced to the DAE core
The sensitizer presented in this work possesses a twisted donor-acceptor (D-A) structure that separates HOMOLUMO and, leads to a narrowed gap between the singlet and triplet energy levels (ΔEST, Fig. 1a)[28,30,31,32]

Summary

Introduction

Current development of light-responsive materials and technologies imposes an urgent demand on visible-light photoswitching on account of its mild excitation with high penetration ability and low photo-toxicity. A dilemma is encountered as the visible-light excitation of the diarylethene is often achieved at the expense of photochromic performances To tackle these setbacks, we introduce a building-block design strategy to achieve all-visible-light photochromism with the triplet-sensitization mechanism. Prolonged or intensified irradiation (even using visible light) will certainly harm the endurance of the fabricated materials To break these limitations and strike a balance between the structure-property relation of the visible-light photoswitching, we present a building-block design of triplet-sensitized photoswitching with both visible-light excitation and enhanced photochromic performances. Our strategy may create a visible-light DAE database for diversified design of solid-state, opto-/electronic materials and bio-systems with photo-controllable functions

Methods

Results

Conclusion