Doubly Encapsulated Perylene Diimides: Effect of Molecular Encapsulation on Photophysical Properties

Intermolecular interactions play a fundamental role on the performance of conjugated materials in organic electronic devices, as they heavily influence their optoelectronic properties. Synthetic control over the solid state properties of organic optoelectronic materials is crucial to access real life applications. Perylene diimides (PDIs) are one of the most highly studied classes of organic fluorescent dyes. In the solid state, π–π stacking suppresses their emission, limiting their use in a variety of applications. Here, we report the synthesis of a novel PDI dye that is encapsulated by four alkylene straps. X-ray crystallography indicates that intermolecular π–π stacking is completely suppressed in the crystalline state. This is further validated by the photophysical properties of the dye in both solution and solid state and supported by theoretical calculations. However, we find that the introduction of the encapsulating “arms” results in the creation of charge-transfer states which modify the excited state properties. This article demonstrates that molecular encapsulation can be used as a powerful tool to tune intermolecular interactions and thereby gain an extra level of control over the solid state properties of organic optoelectronic materials

Suppressing Solid-State Quenching in Red-Emitting Conjugated Polymers

Conjugated polymers with intense solid-state emission are vital for the development of next-generation optoelectronic devices. In particular, it remains extremely challenging to construct π-conjugated systems that emit in the red region of the electromagnetic spectrum and also retain their optical properties and intense photoluminescence in the solid state. In this article we report the synthesis and characterization of three novel diketopyrrolopyrrole-based conjugated polymers, with systematic variation of the covalent encapsulation density. Through control of the distance and density of encapsulation, our red-emitting polymers demonstrate that aggregation-caused quenching can be mostly eliminated, culminating in the most efficient solid-state photoluminescence from red conjugated polymers to date

Simultaneous enhancement of thermally activated delayed fluorescence and photoluminescence quantum yield via homoconjugation

A new iptycene unequivocally validates homoconjugation as a viable strategy to simultaneously enhance TADF reverse intersystem crossing and radiative decay.</jats:p