How Matrixes Influence Room Temperature Ultralong Organic Phosphorescence: 4-Dimethylaminopyridine vs Carbazole Derivative

Abstract

How matrixes influence room temperature ultralong organic phosphorescence (RTUOP) in the doping systems is a fundamental question. In this study, we construct guest-matrix doping phosphorescence systems by using the derivatives (ISO2N-2, ISO2BCz-1, and ISO2BCz-2) of three phosphorescence units (N-2, BCz-1, and BCz-2) and two matrixes (ISO2Cz and DMAP) and systematically investigate their RTUOP properties. Firstly, the intrinsic phosphorescence properties of three guest molecules were studied in solution, in the pure powder state, and in PMMA film. Then, the guest molecules were doped into the two matrixes with increasing weight ratio. To our surprise, all of the doping systems in DMAP feature a longer lifetime but weaker phosphorescence intensity, while all of the doping systems in ISO2Cz exhibit a shorter lifetime but higher phosphorescence intensity. According to the single-crystal analysis of the two matrixes, resemblant chemical structures of the guests and ISO2Cz enable them to approach each other and interact with each other via a variety of interactions, thus facilitating the occurrence of charge separation (CS) and charge recombination (CR). The HOMO-LUMO energy levels of the guests match well with the ones of ISO2Cz, which also significantly promotes the efficiency of the CS and CR process. To our best knowledge, this work is a systematic study on how matrixes influence the RTUOP of guest-matrix doping systems and may give deep insight into the development of organic phosphorescence.

Achieving Colorful Ultralong Organic Room-Temperature Phosphorescence by Precise Modification of Nitrogen Atoms on Phosphorescence Units

“…It is revealed that the ultralong phosphorescence in the powder matrix is from charge separation and charge recombination according to transient absorption. Then, we found that 7 H -benzo­[ c ]­carbazole (BCz), , 5 H -benzo­[ c ]­carbazole (BCz-1), , N -phenyl-1-naphthylamine (N-1), and N -phenyl-2-naphthylamine (N-2) function similarly with Bd in terms of UORTP. Due to the similar phosphorescence properties of these five organic units, we defined them as “ Phosphorescence Unit ”.…”

Triplet-Induced Stable Organic Radical Emitter in Host-Guest Room-Temperature Phosphorescent Materials

“…As the host PXT molecule has low melting point (52 o C), therefore, the radicals are would be quenched due to their enhanced thermal motion. 40,62 This indicates that the irradiated doped material can recover to its original state after melting-recrystallizing procedure. By heating and recrystallization, the color of the powder changed to original white (Fig.…”

“…33,[35][36][37][38] The long lifetime of the excited state provides much more opportunities to photo-induced charge separation between the host and guest. 33,39,40 After the charge separation, the stabilization of the unpaired electrons may offer a new strategy to construct the stable organic radicals. 18,41,42 In addition, a rigid host restricts the molecular motions, thus decreasing the non-radiative decay for the realization of emissive radicals.…”

Photo- and Oxygen- Synergistically Controlled Selective Expression of Organic Phosphorescence Units

“…PMMA and PVA are frequently used as polymer hosts as they can provide a rigid environment to significantly inhibit nonirradiative relaxation of triplet excitons. − Compared with the host, the guest library expands more discretely. Till date, derivatives of 1 H -benzo­[f]­indole (Bd), , 7 H -Benzo­[c]­carbazole (BCz), 5 H -Benzo­[c]­carbazole (BCz-1), , N -phenyl-1-naphthylamine ( N -1), N -phenyl-2-naphthylamine ( N -2), phenylboronic acid, − and so forth have been reported as excellent guests. It is worth mentioning that some guests (such as Bd, BCz, BCz-1, etc.)…”