Influence of Guest/Host Morphology on Room Temperature Phosphorescence Properties of Pure Organic Doped Systems

Guest/host
phosphorescence materials have attracted much attention;
traditionally, researchers have focused on the influence of the electronic
properties and energy levels of the molecules on the phosphorescence
activities. However, the effects of the morphology on the phosphorescence
properties are ignored. Herein, three isoquinoline guests with different
aliphatic rings and three hosts are selected to construct guest/host
materials. Experimental results confirm that the guests are dispersed
in the host in the form of clusters. More importantly, the morphologies
of the guest/host directly affect the phosphorescence properties.
In these systems, the guests have strong intermolecular interactions,
which are beneficial to stabilize the triplet excitons; meanwhile,
the hosts should have weak intermolecular interactions with easily
changed morphology to accept the guest clusters, which synergistically
ensure that the doped materials have excellent RTP properties. This
is the first work focusing on the effect of molecular morphology on
the phosphorescence characteristics of guest/host systems.