Ultralong room-temperature phosphorescence from polycyclic aromatic hydrocarbons by accelerating intersystem crossing within a rigid polymer network

Abstract

Polymer-based room temperature phosphorescence has attracted great attentions for the potential applications in organic light-emitting diodes, sensors, data encryption, and anti-counterfeiting. One of the most applied strategies to realize efficient...

Phosphorescence or Delayed Fluorescence? Fate of Excitons in Core-Substituted Naphthalimide-Derived Emitters and Ratiometric Optical Oxygen Sensors

“…Compared to its pristine films, the increase in phosphorescence intensities and PL lifetimes of Br-NMI doped films was attributed to highly favored radiative transitions (T 1 ) in a crystalline host matrix like PMMA. 19,40,41,45−49 It is known that certain types of polymer matrices assist in improving the SOC 50,51 and, in our case, we noticed a high ISC rate (5 × 10 7 s −1 ) in 10 wt % doped films in PMMA (Table 1). We hypothesize that the strong intramolecular C�O•••Br interactions between the host−guest molecules contributed to SOC enhancement due to the matrix-assisted modified n−π character to the doped systems.…”

“…Several strategies, including polymerization, crystallization, host–guest interactions, etc. , have been widely attempted to reduce nonradiative loss. − Among these, the most common approach is the dispersion of phosphors in a crystalline polymer matrix which provides a rigid environment by introducing various intermolecular interactions like hydrogen bonding and halogen bonding between phosphor and the polymer matrix. − This doped system also promotes the ISC process by enlarging the SOC constant between the S 1 –T n . − But the environmental rigidity is not enough to suppress the nonradiative relaxation of triplet excitons; the triplet state of molecular oxygen can precisely quench the RTP through triplet–triplet energy transfer between phosphor and oxygen under ambient conditions. The oxygen sensitivity enables one pure organic RTP material to act as a quantitative optical oxygen sensor. − Generally, ratiometric optical oxygen sensors involve multi-luminophores consisting of an oxygen-sensitive phosphor and an oxygen-insensitive fluorophore dispersed in an oxygen-permeable polymer matrix [ e.g.…”

Crystal structures, dual-state emissions and polymer-based doped room-temperature phosphorescence of 8-benzyloxyisoquinoline derivatives

“…S9b†), which are attributed to the triplet excitons of the molecules being prone to non-radiative transitions by vibration and rotation of the molecules as well as the influence of quenchers including oxygen and moisture in the air. 9 According to previous reports, 10 because these compounds have phosphorescence at 77 K, a host–guest doping strategy can make RTP emissions possible by inhibiting the non-radiative transitions of the triplet excitons in the rigid microenvironment created by the host. When the isoquinoline derivatives, which are used as the guest molecules, are doped into the host PMMA polymer which has no phosphorescence at room temperature (Fig.…”

Engineering Tunable Ratiometric Dual Emission in Single Emitter‐based Amorphous Systems

“…It gradually returns to the initial state after being under ambient condition for only 60 s, demonstrating a photo-stimulus phosphorescence phenomenon with fast response and reversibility (Figure 4e and S8b). This photoactivation and recovery process is faster than many reported photo-responsive RTP materials [27][28][29][30][31][32][33][34][35][36] and can be compared with some outstanding examples (Figure S9). [37,38] Such dynamically and reversibly photo-controlled RTP behavior can be repeated (Figure 4e).…”