Research Blogs
TADF OLEDs and Hyperfluorescent OLED Simulation with Setfos
Simulation of Organic light‐emitting diodes (OLEDs) using thermally activated delayed fluorescence (TADF). Emission zone analysis and a parameter study. Possible routes for efficiency enhancement.
Influence of recombination rates on transient photoluminescence and efficiency of TADF OLEDs
OLEDs made by thermally-activated delayed fluorescence (TADF) materials as emitters promise an IQE of 100%. Here, we want to present an analysis of the influence of non-radiative recombination rates (knrs and knrt) on the device efficiency as well as how to determine them from experiments. As we will see, the knr rate influences PLQY, and consequently ELQY, hence the negative impact on EQE.
First, to determine the non-radiative decay rates, we need to extract the rates kf, krisc, and kisc by fitting transient photoluminescence (trPL) measurements of TADF films.
3D Master Equation for Exciton dynamics in oleds
We describe a novel simulation approach for excitons in organic light-emitting diodes (OLEDs). We combined a 1D drift-diffusion model with a 3D master equation.
Our approach effectively combines the computational efficiency of a 1D drift-diffusion solver with the physical accuracy of a discrete 3D ME model, where excitonic long-range interactions for energy transfer can be taken into account.
We show that such a hybrid approach can efficiently describe the steady-state and transient behavior of typical OLEDs reported in the literature.
Optimize Hyperfluorescent and TADF OLEDs by Reducing Excitonic Loss Channels
We present a combined experimental/simulation analysis of a set of 4 OLEDs with 2 systematically varied guest dopants in the EML. A numerical electro-optical model is employed, demonstrating one consistent parameter set that describes both steady-state and AC characteristics of all devices. The model accounts for charge transport, trapping, polar layers, and excitonic loss processes. These are inducing an efficiency roll-off that can be correlated with the shape of the emission zone and the guest dopant concentrations. Furthermore, starting from the resulting parameter set, we show routes for optimized TADF OLDEs with a reduced roll-off.