Fig. 2.
Photophysical properties of designed MRL molecules. a Photos of luminogens in crystalline and amorphous states taken under room and UV light irradiation with their quantum yields (Φ). Luminescence contrast ratio: αФ = Φa/Φc. b Fluorescent photos of luminogens in acetonitrile and acetonitrile/water mixtures taken under UV light irradiation, luminogens concentration: 1 × 10−5 M. c Switching the luminescence of TPE-4N film deposited on a weighing paper through different processes: I, heating at 150 °C or fuming with acetone for 10 s; II, grinding with a glass rod; III, heating with a paper mask for 30 s; IV, grinding with a paper mask. All fluorescent photos were taken under UV irradiation at 365 nm. Scale = 2 cm. d Plot of luminescence quantum yields versus repeated grinding and heating cycles