Oxygen-Acceptor-Driven High Photochromic Contrast Solid-State Excited-State Intramolecular Proton Transfer...

Area of Science:

• Organic Smart Materials
• Photochemistry
• Materials Science

Background:

• Developing solid-state photoswitches with high photochromic contrast is a significant challenge.
• Existing organic photoswitches often struggle with performance in solid states.

Purpose of the Study:

• To introduce an oxygen-acceptor strategy for constructing an excited-state intramolecular proton transfer (ESIPT)-inspired organic photoswitch.
• To develop a photoswitch with high photochromic contrast and stability in the solid state.

Main Methods:

• Synthesized a novel organic photoswitch, tpmSA, by incorporating a bulky triphenylmethane into a salicylaldehyde skeleton.
• Investigated photochromic properties under UV light exposure, including color variation and contrast.
• Conducted kinetic and mechanistic studies to understand photoisomerization pathways and fatigue resistance.

Main Results:

• tpmSA demonstrated significant color change from white to yellow upon UV irradiation, achieving a high photochromic contrast (ΔE*_Lab>74).
• The photoswitch exhibited rapid photoisomerization and reversible switching over 20 cycles, indicating superior fatigue resistance.
• Mechanistic studies revealed that the oxygen-acceptor moiety suppressed the ground-state intramolecular proton transfer (GSIPT) pathway, enhancing contrast.

Conclusions:

• The proposed oxygen-acceptor strategy is effective for developing solid-state photoswitches with high photochromic contrast.
• tpmSA shows great potential for applications in advanced information encryption and photopatterning.
• This work offers a new approach for designing high-performance organic smart materials.