3D electrothermal simulations of organic LEDs showing negative differential resistance
- Liero, Matthias
- Fuhrmann, Jürgen
- Glitzky, Annegret
- Koprucki, Thomas
- Fischer, Axel
- Reineke, Sebastian
2010 Mathematics Subject Classification
- 35Q79 35J92 80M12
2008 Physics and Astronomy Classification Scheme
- 72.20.Pa, 72.80.Le, 81.05.Fb, 85.80.Fi, 02.60.Cb
- organic semiconductors, self-heating, negative differential resistance, p-Laplacian, thermistor model, hybrid finite-volume/finite-element scheme
Organic semiconductor devices show a pronounced interplay between temperature-activated conductivity and self-heating which in particular causes inhomogeneities in the brightness of large-area OLEDs at high power. We consider a 3D thermistor model based on partial differential equations for the electrothermal behavior of organic devices and introduce an extension to multiple layers with nonlinear conductivity laws, which also take the diode-like behavior in recombination zones into account. We present a numerical simulation study for a red OLED using a finite-volume approximation of this model. The appearance of S-shaped current-voltage characteristics with regions of negative differential resistance in a measured device can be quantitatively reproduced. Furthermore, this simulation study reveals a propagation of spatial zones of negative differential resistance in the electron and hole transport layers toward the contact.
- Opt. Quantum Electron., 49 (2017), pp. 330/1--330/8, DOI 10.1007/s11082-017-1167-4 .