Controlling the efficient and ultralong room-temperature phosphorescence of 9H-dibenzo[a,c]carbazole derivatives for erasable light printing

Abstract

Two polymer systems containing 9H-dibenzo[a,c]carbazole derivatives showed phosphorescence quantum yields and lifetimes of up to 13.5% and 3.01 s after photoactivation.

Elucidating the Crystallization‐Caused Phosphorescence Quenching Mechanism to Achieve Efficient Photoactivated Persistent Luminescence for High‐Quality Light Printing

“…Intriguingly, upon annealing at 120 °C for ≈70 s, 5 min, and 10 min in the air, respectively, and then cooling down to room temperature, the UOP of E0EP-0.10%, E1EP-0.10%, and E2EP-0.10% was turned off, and the films recovered to the pristine state (Figure 3g). The loss of the persistent luminescence may be attributed to the remarkable chain segment motions of the polymers at a temperature above the glass transition temperature, [10] leading to the permeation of oxygen into the matrices, which thereby quenches the triplet excitons of the guest luminogens again. [9a,b] The activation-deactivation processes of the samples are repeatable, and no apparent changes were observed in intensities, lifetimes, and spectral profiles of their UOP, even though ten cycles were carried out (Figures S40-S42, Supporting Information).…”