Dual emission in purely organic materials for optoelectronic applications

Abstract

In this review, types and mechanisms of dual emission, as well as recent new insights for the design and applications of efficient novel dual emissive organic materials are presented.

Full-colour solvatochromic fluorescence emitted from a semi-aromatic imide compound based on ESIPT and anion formation

“…For instance, dual emission can be obtained one emitter with two emitting states, two independent emitters, or two correlated emitters, and their mechanisms and the electronic or geometrical conditions have been investigated for molecular design and applications. Such materials have been of great interest over the past few years [7,8]. In recent years, aromatic imide/amide molecules have attracted significant attention because of their excellent photothermal and chemical stabilities with rigid structures, high-fluorescence quantum yields, and characteristic electron-transporting properties [9].…”

Phenothiazine–Quinoline Conjugates Realizing Intrinsic Thermally Activated Delayed Fluorescence and Room‐Temperature Phosphorescence: Understanding the Mechanism and Electroluminescence Devices

“…[6d,e] On the other hand, to harvest triplet excitons via TADF with room-temperature phosphorescence (RTP) feature, a very good energy-level tuning of these three excited states should occur at ambient conditions. [8] Designing such organic systems is a difficult task as purely organic materials are intrinsically incapable of efficient phosphorescence at ambient conditions due to fast nonradiative decay pathways (k nr ) of the excited states, [9] although many design principles which rely on intra-and/or intermolecular interactions (lp•••π, π•••π, hydrogen bonding), [10] aggregates, [11] host-guest chemistry, [12] deuteration, [13] and the presence of heavy elements [14] in the molecular backbone have been developed. Recently, few researchers demonstrated simultaneous TADF and RTP from single molecular systems using chemical modification, [15] mechanical force, [8b,16] conformational switching, [17] and change of host matrices.…”

“…[19] Previously, we have demonstrated how dual RTP and TADF can be achieved. Inspired by these studies, [8] we designed phenothiazine(D)-quinoline(A) conjugates (Figure 1) with the aim of efficient TADF with RTP due to well-matched excited energy levels ( 3 LE, 1 CT, 3 CT). Here, we designed two new systems by modifying electron donor groups onto the acceptor part of the naphthyl-appended phenothiazine(D)-quinoline(A) conjugates (PTzQ1, PTzQ2) without changing the donor part.…”

The Journey to Precious‐Metal‐Free Organic Phosphors from Single‐Benzene‐Cored Fluorophores

“…Dual emission of fluorescence and phosphorescence at room temperature would be very useful in various fields such as bio‐imaging, data security, white‐light luminescence, and ratiometric luminescence sensing [40] . In particular, dual emissions in which the steady‐state spectrum is bimodal and both emission peaks of fluorescence and RTP are easily discernable without time‐gated luminescence measurements would be very attractive for such applications [41] .…”