Luminescence of doublet molecular systems

Luminescent molecules are functional materials that are attractive for use in various fields such as in light-emitting devices and bio-imaging. These molecules generally possess a closed-shell singlet ground state and show fluorescence from the lowest singlet excited state or phosphorescence from the lowest triplet excited state. This review focuses on open-shell luminescent molecules with spin doublet ground states such as organic radicals, radical-ligated metal complexes, and metal complexes with magnetic metal ions as a rapidly growing class of molecular emitters. They exhibit unique luminescence properties that originate mainly from their emissions being based on the spin-allowed doublet-doublet transition. Their emission properties, responsiveness to external stimuli and environments, and photo functional applications described here make doublet molecular systems promising solutions to problems that are intractable using conventional closed-shell molecular systems. These luminescent doublet molecular systems will provide a seminal perspective on molecular photochemistry. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This review discusses open-shell luminescent molecular systems with spin doublet ground states, including organic radicals, radical-ligated metal complexes, and metal complexes with magnetic metal ions. These molecular systems exhibit unique luminescent properties and have promising applications in various light functional applications.