CAREER: Phosphorescent Organic Light Emitting Diode Materials Featuring Multidentate Carborane-Based Ligands

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

In this CAREER project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Alexander Spokoyny of the Department of Chemistry and Biochemistry at the University of California, Los Angeles (UCLA) are developing new luminescent transition metal-based complexes featuring boron cluster building blocks for use in luminescent lighting applications. The goal of this research is to use these unique boron cluster-based scaffolds to create stable and efficient deep blue emitters for use in organic light emitting diode (OLED) devices, potentially resulting in the next generation of television screens, mobile phone displays, and solid-state lighting sources. The project lies at the interface of synthetic inorganic, organometallic and materials chemistry, and is well suited for the education and training of scientists at all levels. Three key target audiences were chosen for outreach, which include middle and high school students through experimental summer science camps, and inmate members of the California Institute for Women (CIW) as part of the UCLA Prison Education project. These educational and outreach activities create excitement towards the potential positive changes scientific careers can hold for younger students. This project centers on the development of new photophysically-innocent ligand scaffolds based on polyhedral boron clusters. Currently utilized classical polyaromatic ligands attached to metal centers within the flat square planar geometry can lead to undesirable color dilution and non-radiative decay pathways due to intermolecular stacking interactions. Boron clusters are used to counteract these issues providing the three-dimensional steric bulk capable of minimizing intermolecular interactions in the solid-state. Furthermore, boron cluster ligands are synthetically appealing, given that they place functional groups at specific vertices, thus allowing for a large degree of tunability. In this project, new substitution chemistry is used to tune the emitter color through the ligand coordinated to the platinum(II)center. Furthermore, boron cluster species may provide extraordinarily large frontier orbital gaps in their unfunctionalized form, making them photophysically innocent in the context of designing metal-based phosphorescent emitters. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.