Molecular mechanism of aggregation‐induced emission

Aggregate, Journal Year: 2021, Volume and Issue: 2(5)

Published: June 3, 2021

Abstract Deep understanding of the inherent luminescence mechanism is essential for development aggregation‐induced emission (AIE) materials and applications. We first note that intermolecular excitonic coupling much weaker in strength than intramolecular electron‐vibration a majority newly termed AIEgens, which leads to peak position insensitive coupling, hence conventional model J‐aggregation cannot effectively explain their AIE phenomena. Then, using multiscale computational approach coupled with our self‐developed thermal vibration correlation function rate formalism transition‐state theory, we quantitatively investigate aggregation effect on both radiative nonradiative decays molecular excited states. For decay processes, propose lowest state could convert from transition dipole‐forbidden “dark” dipole‐allowed “bright” upon aggregation. radiationless demonstrate blockage via relaxation (BNR‐VR) harmonic region or removal isomerization (RNR‐ISO) minimum energy crossing point (RNR‐MECP) beyond variety aggregates. Our theoretical work not only justifies plethora experimental results but also makes reliable predictions design can be experimentally verified. Looking forward, believe this review will benefit deep about universality phenomenon further extending scope systems novel

Language: Английский

---

Dual Emission: Classes, Mechanisms, and Conditions

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(42), P. 22624 - 22638

Published: Aug. 12, 2020

There has been much interest in dual-emission materials the past few years for and life science applications; however, a systematic overview of underlying processes is so-far missing. We resolve this issue herein by classifying (DE) phenomena as relying on one emitter with two emitting states (DE1), independent emitters (DE2), or correlated (DE3). Relevant DE mechanisms are then briefly described together electronic and/or geometrical conditions under which they occur. For further reading, references given that offer detailed insight into complex mechanistic aspects various provide overviews families their applications. By avoiding ambiguities misinterpretations, systematic, insightful Review might inspire future targeted designs materials.

Language: Английский

---

Luminescence in Crystalline Organic Materials: From Molecules to Molecular Solids

Advanced Optical Materials, Journal Year: 2021, Volume and Issue: 9(13)

Published: April 30, 2021

Abstract Luminescent small, all‐organic molecules are of tremendous interest in materials and life science applications. Nevertheless, targeted design requires a basic understanding the excited state deactivation pathways themselves, modulations processes that occur solid state. This particularly concerns crystalline molecular solids, as here not only solid‐state rigidification contributes to these modulations, but specific intermolecular interactions well. Starting from properties, this work carefully disentangles all intramolecular factors radiative nonradiative solids provide guidelines for design.

Language: Английский

---

Principles of Aggregation‐Induced Emission: Design of Deactivation Pathways for Advanced AIEgens and Applications

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(25), P. 9856 - 9867

Published: March 10, 2020

Twenty years ago, the concept of aggregation-induced emission (AIE) was proposed, and this unique luminescent property has attracted scientific interest ever since. However, AIE denominates only phenomenon, while details its underlying guiding principles remain to be elucidated. This minireview discusses basic based on our previous mechanistic study photophysical behavior 9,10-bis(N,N-dialkylamino)anthracene (BDAA) corresponding analysis by quantum chemical calculations. BDAA comprises an anthracene core small electron donors, which allows aspects discussed. The key factor for is control over non-radiative decay (deactivation) pathway, can visualized considering conical intersection (CI) a potential energy surface. Controlling surface enables separate formation fluorescent (CI:high) non-fluorescent (CI:low) molecules [control accessibility (CCIA)]. novelty originality in field photochemistry lies creation functionality design active deactivation pathways. Moreover, we provide new strategy luminogens (AIEgens) discuss selected examples.

Language: Английский

---

ESIPT‐based AIE luminogens: Design strategies, applications, and mechanisms

Aggregate, Journal Year: 2022, Volume and Issue: 3(5)

Published: Jan. 26, 2022

Abstract In this review, we present a systematic and comprehensive summary of the recent development applications excited‐state intramolecular proton transfer‐based (ESIPT‐based) aggregation‐induced emission luminogens (AIEgens), type promising materials that inherit advantages ESIPT AIE, such as large Stokes shift, excellent photostability, low self‐quenching. We first summarize backbones have been used to construct ESIPT‐based AIEgens classify constructed ones based on relation between AIE unit. According sensing mechanisms design strategies, reviewed in bioimaging, drug delivery systems, organic light‐emitting diodes, photo‐patterning, liquid crystal, detection metal cations, anions, small molecules, biothiols, biological enzymes, latent fingerprinting, so on. also advances new theoretical methods for investigating molecular photochemistry crystals their AIEgens. discussed remaining challenges field issues need be addressed. anticipate review can provide picture current condition research field, promote researchers make more efforts develop novel with applications.

Language: Английский

---

Dual-State Emission (DSE) in Organic Fluorophores: Design and Applications

Chemistry of Materials, Journal Year: 2021, Volume and Issue: 33(18), P. 7160 - 7184

Published: Sept. 15, 2021

Organic luminescent materials have attracted significant attention in the past few years due to their fascinating photophysical properties. Implementing these emissive organic compounds is now being actively pursued many applications solution (i.e., sensors, bioimaging) or solid forms optoelectronic devices data encryption). Despite advances development of compounds, there has been an increasing quest decade for where emission preserved both states, dual-state (DSE). These are expected detonate a myriad future. On this nascent topic, work addresses several factors that increase probability obtaining property based on precedent reports showing phenomenon. Therefore, review identifies and organizes different structural characteristics useful obtain compounds. In addition, it devised motivate discussion science community hopefully incentivize efforts research groups around world toward synthesis new emitters.

Language: Английский

---

Restriction of Access to the Dark State: A New Mechanistic Model for Heteroatom‐Containing AIE Systems

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(42), P. 14911 - 14914

Published: July 25, 2019

Restriction of intramolecular motion (RIM), as the working mechanism aggregation-induced emission (AIE), cannot fully explain some heteroatom-containing systems. Now, two excited states are taken into account and a mechanism, restriction access to dark state (RADS), is specified elaborate RIM complete picture AIE mechanism. A nitrogen-containing molecule named APA chosen model compound; its weak fluorescence in solution ascribed easy from bright (π,π*) close-lying (n,π*) state. By either metal complexation or aggregation, less accessible due molecular leading elevation energy, thus restored. RADS powerful elucidating effect molecules with favoring non-radiative decay, including overlap-forbidden such CT states, spin-forbidden triplet so on.

Language: Английский

---

Through-Space Interaction of Tetraphenylethylene: What, Where, and How

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(17), P. 7901 - 7910

Published: April 21, 2022

Electronic conjugation through covalent bonds is generally considered as the basis for electronic transition of organic luminescent materials. Tetraphenylethylene (TPE), an efficient fluorophore with aggregation-induced emission character, fluoresces blue in aggregate state, and such photoluminescence always ascribed to through-bond (TBC) among four phenyl rings central C═C bond. However, this work, systematic spectroscopic studies DFT theoretical simulation reveal that intramolecular through-space interaction (TSI) between two vicinal generates bright TPE but not TBC effect. Furthermore, evaluation excited-state decay dynamics suggests significance photoinduced isomerization nonradiative solution state. More importantly, different from traditional qualitative description TSI, quantitative elucidation TSI realized atoms-in-molecules analysis; meanwhile, a solid-state model other multirotor systems studying configuration preliminarily established. The mechanistic delineated work provides new strategy design materials beyond theory expands quantum understanding molecular behavior level.

Language: Английский

---

Restriction of Intramolecular Motion(RIM): Investigating AIE Mechanism from Experimental and Theoretical Studies

Chemical Research in Chinese Universities, Journal Year: 2021, Volume and Issue: 37(1), P. 1 - 15

Published: Jan. 15, 2021

Language: Английский

---

Consideration of Molecular Structure in the Excited State to Design New Luminogens with Aggregation‐Induced Emission

Angewandte Chemie, Journal Year: 2019, Volume and Issue: 131(26), P. 8724 - 8731

Published: Feb. 28, 2019

Abstract Aggregation‐induced emission (AIE) is a photoluminescence phenomenon in which an AIE luminogen (AIEgen) exhibits intense the aggregated or solid state but only weak no solution state. Understanding mechanism of requires consideration excited molecular geometry (for example, π twist). This Minireview examines history AIEgens with focus on representative AIEgen, tetraphenylethylene (TPE). The mechanisms solution‐state quenching are reviewed and crucial role excited‐state transformations for discussed. Finally, recent progress understanding relationship between overviewed range different AIEgens.

Language: Английский

---