Towards high contrast photochromism materials via fluorinated TPE-based medium ring

Unsymmetrical and C3-Symmetrical Partially Fluorinated Hexaarylbenzenes: Effect of Terminal Alkoxy Chain Length on Photophysical and Thermophysical Behavior

“…According to the PL spectral shapes shown in Figure 4a,c, in addition to the PL band on the short-wavelength side, PL bands or broad shoulder peaks were observed in the long-wavelength region. This phenomenon was also observed visually, and when a white crystal sample of 1e was irradiated with 323 nm excitation light, it turned yellow (Figure 5) The observed phenomenon is photochromism in the crystalline state, which causes a color change when irradiated with light [20][21][22], however, to our knowledge, there are only limited reports on fluorinated photochromism materials [23,24]. Partially fluorinated HABs are considered novel crystalline photochromic molecules.…”

“…Figure 6 depicts the PL spectra and color changes before and after UV irradiation. The observed phenomenon is photochromism in the crystalline state, which causes a change when irradiated with light [20][21][22], however, to our knowledge, there are only limited reports on fluorinated photochromism materials [23,24]. Partially fluorinated HABs are considered novel crystalline photochromic molecules.…”

“…The photochromism induced by these compounds is expected to be based on a 6π-electrocyclization between adjacent aromatic rings upon UV irradiation, and the reason why the reverse reaction is unlikely to occur has not yet been elucidated. The observed phenomenon is photochromism in the crystalline state, which causes a color change when irradiated with light [20][21][22], however, to our knowledge, there are only limited reports on fluorinated photochromism materials [23,24]. Partially fluorinated HABs are considered novel crystalline photochromic molecules.…”