Quantifying Interdopant Exciton Processes in Organic Light Emitting Diodes

Interdopant exciton transfer processes play a critical role in engineering emission spectra from multiple emitters in white organic light emitting diodes (OLEDs). Developing experimental techniques for probing these energy transfer processes are thus vital to gain a better understanding of the device physics and to eventually engineer better white OLEDs. In this article, we present a simple method, based on electroluminescence spectra, to study and quantify the energy transfer mechanisms in a two-dopant (triplet singlet) system. Through a combination of experimental spectra obtained from a collection of donor acceptor separations and theoretical simulations of spectral variations, we demonstrate that the key physical parameters such as the Dexter van der Waals radii and the Forster radius can be quantified.