Construction of a viologen-derived 2D material with photochromism, photoswitchable luminescence and inkless and erasable prints via sunlight irradiation

Abstract

Utilizing the energy of sunlight is an attractive green prospect and thus extending the photoinduced energy to the visible spectrum is of great significance to the better utilization of solar energy in the research of photochromic materials. In this work, a viologen-derived Zn(II) material with the molecular formula [Zn(tdc)(cpbpy)]_n (1) has been synthesized by using 2,5-thiophenedicarboxylic acid (H₂tdc) and N-(3-carboxypyridin-5-yl)-4,4′-bipyridinium (cpbpy) ligands under solvothermal conditions. Compound 1 features a 2-fold interpenetrating 2D structure, exhibiting photochromic properties upon sunlight or visible-light irradiation via radical formation. Meanwhile, solid-state luminescence behaviors of 1 could be reversibly modulated during the photochromic process. Importantly, the compound shows its potential application as an inkless and erasable print medium via sunlight irradiation.