Research topics

Excited spices in organic semiconductors generated by photon or electrical excitation can relax to the ground state in radiative or non-radiative manner. The emissive relaxation plays an important role for their applications in light emitting devices, while dark processes are kinetically completion loss channels.
The purpose of this sub-project is to quantitatively investigate the excition dynamic for both the emissive and dark processes. Afterwards, different kinetic models were be used to understand the measured experimental results. 

Related publications:
1. Li, Y.; Jiang, L.; Liu, W.; Xu, S.; Li, T.; Fries, F.; Zeika, O.; Zou, Y.; Ramanan, C.; Lenk, S.; Scholz, R.; Andrienko, D.; Feng, X.; Leo, K.; Reineke, S. Reduced Intrinsic Non‐Radiative Losses Allow Room‐Temperature Triplet Emission from Purely Organic Emitters. Adv. Mater. 2021, 33 (39), 2101844. https://doi.org/10.1002/adma.202101844.

2. Zhou, X.; Nikan, J.; Guo, K.; Blom, P. W. M.; Wetzelaer, G. J. A. H.; Li, Y. Determination of the Kinetic Rates and Intrinsic Nonradiative Losses in Organic Thermally Activated Delayed Fluorescence Emitters. Adv. Sci. 2025, e05338. https://doi.org/10.1002/advs.202505338.

3. Dou, D.; Yang, Q.; Zhou, X.; Liu, W.; Tan, X., Ugur, N.; Li, C.; Ramanan, C.; Liu, X.;, Wetzelaer, G. J. A. H., Andrienko, D.; Baumgarten, M., Blom, P. W. M.; Li, Y., Simultaneous delayed fluorescence and phosphorescence in organic luminescent material employing multiple excited states, Light Sci. Appl. , 2026, 15:4 . https://doi.org/10.1038/s41377-025-02063-x. 


 


 

 


 

Light generated from emissive excitons inside light emitting diodes can only partially escape the device cavity. Significant light trapping is observed because of total internal reflection and light coupling into the metallic electrode surface.  In this sub-project, we try to understand the light dissipation from the device cavity.  The aim is to develop efficient and stable light emitting devices.

Related publications:

1. Li, Y.; Van der Zee, B.; Tan, X.; Zhou, X.; Wetzelaer, G. A. H.; Blom, P. W. M. Enhanced Operational Stability by Cavity Control of Single‐Layer Organic Light‐Emitting Diodes Based on Thermally Activated Delayed Fluorescence. Adv. Mater. 2023, 35 (49), 2304728. https://doi.org/10.1002/adma.202304728.

2. Tan, X.; Dou, D.; Chua, L.; Png, R.; Congrave, D. G.; Bronstein, H.; Baumgarten, M.; Li, Y.; Blom, P. W. M.; Wetzelaer, G. A. H. Inverted Device Architecture for High Efficiency Single-Layer Organic Light-Emitting Diodes with Imbalanced Charge Transport. Nat. Commun. 2024, 15 (1), 4107. https://doi.org/10.1038/s41467-024-48553-1.

3. Van der Zee, B.; Li, Y.; Wetzelaer, G. A. H.; Blom, P. W. M. Efficiency of Polymer Light‐Emitting Diodes: A Perspective. Adv. Mater. 2022, 34 (13), 2108887. https://doi.org/10.1002/adma.202108887.