  Most materials recently developed for room temperature phosphorescence (RTP)
lack of practical relevance due to their inconvenient crystalline morphology.
Using amorphous material systems instead, programmable luminescent tags (PLTs)
based on organic biluminescent emitter molecules with easy processing and
smooth sample shapes were presented recently. Here, the effective quenching of
the emitters RTP by molecular oxygen (O2) and the consumption of the excited
singlet O2 through a chemical reaction represent the central features. With
customized activation schemes, high resolution content can be written and later
erased multiple times into such films, providing a versatile yet simple
photonic platform for information storage. However, two important limitations
remain: (i) The immutable fluorescence of the emitters outshines the
phosphorescent patterns by roughly one order of magnitude, allowing read-out of
the PLTs only after the excitation source is turned off. (ii) The programming
of these systems is a rather slow process, where lowest reported activation
times are still > 8 s. Here, a material-focused approach to PLTs with fast
activation times of 120 +/- 20 ms and high-contrast under continuous-wave (cw)
illumination is demonstrated, leading to accelerated programming on industry
relevant time scales and a simplified readout process both by eye and low cost
cameras.
