Dual Guests Synergistically Tune the Phosphorescence Properties of Doped Systems through Chemical Interactions with Bases

Abstract

It is a trend to construct multicomponent room temperature phosphorescence/RTP doped materials in the future to improve phosphorescence performance by using the advantage that the host in the doped system can be used as a container containing other components. Herein, the multicomponent doped systems are constructed with two isoquinoline derivatives (OxISQ and PrISQ) as the guests, diphenyl sulfoxide/SDB as the host, and alkali (KOH) as the fourth component. Bicomponent doped material OxISQ/SDB has strong cyan RTP, whereas PrISQ/SDB has almost no RTP activity. The effect of KOH on the phosphorescence intensity of OxISQ/SDB is excitation-dependent. When λex = 365 nm, KOH turns off the phosphorescence emission, revealing the intensity of KOH-added three-component doped material OxISQ/SDB/KOH is significantly weaker than that of OxISQ/SDB, whereas KOH exhibits the turn-on property for OxISQ/SDB at λex = 385 nm. For PrISQ/SDB, KOH displays permanent turn-on ability, and PrISQ/SDB/KOH has strong yellow-orange RTP. More deeply, a two-guest four-component doped system OxISQ/PrISQ/SDB/KOH is constructed, and from OxISQ/PrISQ/SDB to OxISQ/PrISQ/SDB/KOH, with the increase of KOH, the phosphorescence colors gradually change from cyan to green to yellow to orange at λex = 365 nm, but the color only can change directly from cyan to yellow-orange at λex = 385 nm. In addition, OxISQ/PrISQ/SDB/KOH exhibited a time-dependent afterglow color from orange-yellow to cyan over 2 s due to the different phosphorescence lifetime, intensity, and wavelength of each component. The experimental results confirmed that phenylhydroxyl-containing guests react with KOH to form organic salts, thereby inducing new excitation and emission wavelengths in the doped materials. This work is the first to construct a four-component doped system with dual guests that can undergo chemical reactions. Moreover, taking advantage of the water solubility of KOH, the doped materials have achieved advanced anticounterfeiting writing and printing in the aqueous phase.

Efficient blue TADF-type organic afterglow materialviaboric acid-assisted confinement

“…1,7,12,13 Unfortunately, achieving efficient and long-lived RTP or afterglow is hindered by the spin-forbidden nature of triplet exciton transition, the rapid non-radiative decay of the triplet excitons, and proneness to quenching by oxygen and solvents. 2,14,15…”

“…1,7,12,13 Unfortunately, achieving efficient and long-lived RTP or afterglow is hindered by the spin-forbidden nature of triplet exciton transition, the rapid non-radiative decay of the triplet excitons, and proneness to quenching by oxygen and solvents. 2,14,15 To achieve efficient and long-lived RTP, many strategies have been proposed to promote the intersystem crossing (ISC) process and to stabilize the excitons at triplet states, such as introducing of heavy atoms, lone pair electrons, clusterization, host-guest interactions, crosslinking and matrix rigidification. 1,5,14,[16][17][18][19] Although these strategies have greatly improved the emission efficiencies and lifetime, most of the emission bands of organic afterglow materials located in the wavelength range from 500 to 600 nm, due to the bathochromic shifts and relatively low-lying exciton energies modulated by these strategies.…”

Stimulus-Responsive Organic Phosphorescence Materials Based on Small Molecular Host–Guest Doped Systems

“…(d) Photographs of the OxISQ-PrISQ/SDB doped materials with different molar ratios of KOH under different excitation sources. Reproduced with permission from ref . Copyright 2022 American Chemical Society.…”

“…Recently, Lei et al constructed a dual-guest threecomponent doped system, which allowed for the adjustment of the photophysical properties of doped materials via the introduction of a base as the fourth component to chemically interact with the guests. 89 In the design of stimulus-responsive materials, the interaction with various bases was achieved through the introduction of a benzene hydroxyl group into isoquinoline derivatives (OxISQ and PrISQ) (Figure 9c). The difference in the intramolecular charge transfer effect of the guests led to different phosphorescence performance of twocomponent doped materials.…”

Simple Stimulus-Responsive Organic Long Persistent Luminescence Systems Based on Methoxy-Functionalized Triphenylphosphine

“…Compared to nitrogen atoms in the same main group, phosphorus atoms have unique electronic properties. For example, the lone pair of electrons on the central phosphorus atom provides the possibility for the n → π* transition. − In addition, chemically modifying and generating Lewis acid base pairs are straightforward. − Notably, the energy gap (Δ E ST ) between the lowest singlet (S 1 ) and triplet (T 1 ) excited states of triphenylphosphine (TPP; Δ E ST = 0.227 eV) is significantly reduced compared to that of triphenylamine (TPA; Δ E ST = 0.529 eV) (Figure ). − It is expected to provide a new channel for the construction of functional pure organic room-temperature phosphorescent materials and open a new chapter in organophosphorus chemistry.…”