Tunable Phosphorescence/Fluorescence Dual Emissions of Organic Isoquinoline‐Benzophenone Doped Systems by Alkoxy Engineering

Abstract

Dual/multi-componento rganic doped systems with room-temperature phosphorescence (RTP) properties have been developed. However,t he unknown luminescence mechanism stillg reatly limits the development of the doped materials. Herein, an ew doped system exhibiting phosphorescence/fluorescence dual emission (F phos = 4-24 %a nd t phos = 101-343ms) is successfully constructed throughp rediction and design. As eries of isoquinoline derivatives with different alkoxyc hains were selecteda s the guests. Benzophenonew as chosena st he host owing to the characteristics of low melting point and good crystallinity. The alkoxy chain lengths of the guestsa re first reported to be used to control the fluorescence and phosphorescence intensitieso ft he doped materials,w hich results in different prompt emission colors. Additionally,t he doped ratio of the guest and host can also control the luminousi ntensitiesof the materials. In particular, the doped materialss till exhibit phosphorescent properties even if the ratio of the guest/host is as low as 1:100 000. Ultralong organic room-temperature phosphorescence (RTP) systemsw ith persistentl uminescence have great advantages in structured iversity,m ultiple functionality,a nd biocompatibility. [1] Therefore, RTP materials have attracted wide attention in the fields of anti-counterfeiting, optical recording, and biological imaging. [2] Generatinga sm any triplet excitons as possible and inhibiting the non-radiativet ransitions of excitons to the greatest extent are the key factorsf or the materials to exhibit Scheme1.Schematicdiagram of the host-guest-doped systems.

Recent Advances on Host–Guest Material Systems toward Organic Room Temperature Phosphorescence

“…The RTP properties of the doped system can be efficiently modulated through regulation of the quantities of halogen atoms of the guests, enabling the highest phosphorescent quantum efficiencies and lifetimes up to 64% and 628 ms, respectively. In 2020, Huang and co-workers [165] also used H18 as matrix and alkoxy modified isoquinoline derivatives (G74-G79) as guests to develop a set of host-guest RTP systems. These materials demonstrated tunable phosphorescence-fluorescence properties through tuning the alkoxy chain lengths and concentrations of the guests, thus enabling different steady-state emission colors with phosphorescent lifetime up to 343 ms and quantum yields up to 24%.…”

Red-Emissive Organic Room-Temperature Phosphorescence Material for Time-Resolved Luminescence Bioimaging

“…24 The host matrix not only provides a rigid environment to restrict movement, but also serves as a bridge to facilitate ISC between singlet and triplet of guest. 24,[44][45][46][47][48][49] Herein, we propose a strategy to achieve highly efficient red phosphorescence emission via the combination of molecular engineering and host-guest system (Scheme 1). Two methylene groups were introduced into 1,2,5-triphenyl-1H-pyrrole (TPPy) to lock the molecular conformation and extend its conjugation (Scheme 1a).…”

Highly Efficient Heavy Atom Free Room Temperature Phosphorescence by Host-Guest Doping

“…BPO was chosen as the host due to the characteristics of low melting point, good crystallinity, and phosphorescent features. According to the literature ( Chen et al, 2020 ; Liu et al, 2021b ), the host matrix is believed to play a synergistic role in energy transfer during the phosphorescence emission of the guest molecule, so the abundant lone-pair electrons of TTR are obviously beneficial for energy transfer. The low melting point of BPO (48.5°C) promotes the preparation of the doped materials by the melt-casting method, and the good crystallinity is beneficial to provide a rigid environment for the guest molecule ( Chen et al, 2020 ).…”