The new BBOs have been used to make BBO-based polymer light emitting diodes with luminous efficiencies that are three-fold higher than previously reported, and ISU is seeking commercialization partners for this technology.
Benzobisoxazoles (BBOs) have potential for use as building blocks in the creation of semiconducting polymers because they increase the electron affinity, electron transport, and oxidative and thermal stability of materials incorporating them. In addition, the starting materials for synthesis of BBOs are low cost, allowing for economical large scale production. However, the use of polybenzobisoxazoles has been limited by their poor solubility and prossessivity; since they tend to pi-stack, the morphology of films cast from them can be affected. In addition, research on n-type (electron accepting, electron transporting) organic materials has lagged behind that of p-type (electron accepting, hole transporting) because their synthesis is difficult, limiting structural modifications directed at optimization of properties such as solubility, electron affinity, and electron mobility. To overcome these limitations, ISU researchers have developed new BBO copolymers that incorporate the beneficial properties of the BBO moiety while improving solubility and processivity by disrupting pi-stacking between polymer chains. As a consequence, efficient synthesis of solution processable, tunable, n-type co-polymers is enabled, and the utility of these new BBOs has been demonstrated by fabricating organic light emitting devices with increased luminous efficiencies.