Photoinduced Reversible Heteroepitaxial Microcrystal Growth of a Photochromic Diarylethene on (110) Surface of SrTiO₃

Abstract

Diarylethene 1 shows reversible transformation between the open-ring isomer (1o) and the closed-ring isomer (1c) by alternate UV and visible light irradiation, accompanied with reversible melting and crystallization of the microcrystalline film of 1 at 67 °C, which is the eutectic temperature of 1o and 1c. The reversible epitaxial crystal growth of an 1o of a diarylethene derivative was observed on a 110 surface of a strontium titanate (SrTiO3) single crystal by maintaining a constant temperature and monitoring six reversible intensity changes (within 2 h of repeating cycles) of the reflection of 004 of 1o on XRD measurements.

Photoinduced Self-Epitaxial Crystal Growth of a Diarylethene Derivative with Antireflection Moth-Eye and Superhydrophobic Lotus Effects

“…This is quite unexpected since the results were obtained on a glass substrate. In addition, needle-shaped crystals always stand in good order on any substrate, in contrast with our previous diarylethene derivatives, − e.g., the needle-shaped crystals of 2o on the (110) surface of a SrTiO 3 single-crystal substrate, formed by photoinduced epitaxial crystal growth never stood and superhydrophobicity was not achieved …”

“…In addition, needle-shaped crystals always stand in good order on any substrate, in contrast with our previous diarylethene derivatives, 17−21 e.g., the needle-shaped crystals of 2o on the (110) surface of a SrTiO 3 single-crystal substrate, formed by photoinduced epitaxial crystal growth never stood and superhydrophobicity was not achieved. 21 We here report that the mechanism of growth of the standing needle-shaped 3c crystals on the surface are due to the epitaxial growth over the crystal lattice of 3o without using special inorganic single-crystal substrates [we call this Self-Epitaxial Crystal Growth (SECG)]. We also found that the surface displayed not only excellent superhydrophobicity, but also the anti-reflective moth-eye effect.…”

“…We have reported the surface topographical changes of the microcrystalline surface of diarylethenes 1o and 2o , accompanied by wettability changes, which are controlled by alternate irradiation with UV and visible light. − However, the direction of the photogenerated needle-shaped crystals was randomly oriented, and their sizes were larger than 1 μm in diameter and 10 μm in length. Compared with superhydrophobic surfaces with high contact angle (CA), − these crystals should be smaller (e.g., less than 1 μm in diameter) and ordered alignment was required in order to attain superhydrophobicity with the CA of a water droplet that exceeds 170°.…”

Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators

“…Uchida and co-workers − demonstrated the change in the surface topology by the crystal growth of a photochromic diarylethene upon irradiation with UV light. Figure shows changes of the contact angle of a water droplet on a microcrystalline film of 1,2-bis­(2-methoxy-5-trimethylsilyl-3-thienyl)­perfluorocyclopentene ( 469 ).…”

Solvothermal synthesis and visible light-driven photocatalytic degradation for tetracycline of Fe-doped SrTiO3

“…2f), similar to that of pure STO. 33 Combining the SEM and TEM images, it can be concluded that doping affects the morphology of the materials, both the macroscopic morphology and the interplanar spacing.…”