Thermodynamic Limit for Excitonic Light-Emitting Diodes

Noel C. Giebink, Stephen R. Forrest

Research output: Contribution to journalArticlepeer-review


We derive the thermodynamic limit for organic light-emitting diodes (OLEDs), and show that strong exciton binding in these devices requires a higher voltage to achieve the same luminance as a comparable inorganic LED. The OLED overpotential, which does not reduce the power conversion efficiency, is minimized by having a small exciton binding energy, a long exciton lifetime, and a large Langevin coefficient for electron-hole recombination. Based on these results, it seems likely that the best phosphorescent and thermally activated delayed fluorescence OLEDs reported to date approach their thermodynamic limit. The framework developed here is broadly applicable to other excitonic materials, and should therefore help guide the development of low voltage LEDs for display and solid-state lighting applications.

Original languageEnglish (US)
Article number267002
JournalPhysical review letters
Issue number26
StatePublished - Jun 30 2023

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy

Cite this