Halogen-Bond-Assisted Photoluminescence Modulation in Carbazole-Based Emitter

Jagadish K Salunke,Timo Laaksonen,Paola Vivo,Nikita A Durandin,Arri Priimagi,Elina Vuorimaa-Laukkanen,Tero-Petri Ruoko,Nuno R Candeias

doi:10.1038/s41598-018-32830-3

Jagadish K Salunke, Timo Laaksonen + Show 6 more

Open Access

https://doi.org/10.1038/s41598-018-32830-3

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Journal: Scientific Reports	Publication Date: Sep 26, 2018
Citations: 23	License type: open-access

Affiliation: Tampere University

Abstract

Halogen bonding between a carbazole-based, pyridine-substituted organic semiconductor and a common halogen-bond donor (pentafluoroiodobenzene) yields efficient halogen-bond-driven fluorescence modulation in solution. Steady-state, time-resolved emission and absorption spectroscopy as well as density functional theory studies demonstrate that the fluorescence modulation arises from halogen-bond-induced intramolecular charge transfer. Fluorescence modulation offers a range of possibilities both in solution and in the solid state, for instance providing a potential pathway for the design of tunable luminescent materials for light-emitting devices.

Highlights

Organic luminescent materials are central to a wealth of functional devices, ranging from organic light-emitting diodes (OLEDs) and sensor elements to photonic components and imaging systems[1,2,3,4]
A was obtained by using a simple one-step Suzuki
Coupling reaction of a previously reported bromo-substituted carbazole[39] with a commercially available pyridine boronic-acid pinacol ester in 70% yield (Fig. 1a; further details given in the SI)

Summary

Introduction

Organic luminescent materials are central to a wealth of functional devices, ranging from organic light-emitting diodes (OLEDs) and sensor elements to photonic components and imaging systems[1,2,3,4]. Halogen bonding (XB) has emerged as a prominent noncovalent interaction for the design of supramolecular photofunctional materials[20,21]. It is defined as an attractive interaction between an electrophilic region associated with a halogen atom in a molecule, and a nucleophilic site[22]. We show that halogen-bond-induced intramolecular charge (ICT) in carbazole derivatives efficiently modulates their fluorescence emission in solution. We believe this finding to be important for rationally designing solid-state halogen-bonded emissive materials

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Conclusion