Effect of a sensing layer on triplet exciton diffusion in organic films

Abstract

Measuring the luminescence of inserted sensing layers with high phosphorescent efficiency is an effective way of investigating the triplet exciton diffusion in nonemitting host materials. Researchers used to adopt simple models without taking the influence of doped layers into account. In this Brief Report, to include the dopant effects, a ``double-layer'' model is proposed for describing the exciton diffusion in doped and pure layers separately. The triplet diffusion lengths in $\mathrm{Ir}{(\mathrm{ppy})}_{3}$-doped and pure $4,{4}^{\ensuremath{'}}\text{\ensuremath{-}}N,{N}^{\ensuremath{'}}$-dicarbazole-biphenyl films are calculated to be 6.8 and $61.4\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, respectively.