The doctoral dissertation in the field of Chemistry will be examined at the Faculty of Science, Forestry and Technology, Joensuu campus.
What is the topic of your doctoral research? Why is it important to study the topic?
The research focuses on the comprehensive computational study and experimental validation of gold-centered carbene–metal–amide (CMA) complexes as thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs), using DFT/TD-DFT to establish structure–property relationships and predictive design rules.
OLEDs are key to modern display and lighting technologies, but efficient emission typically relies on scarce and expensive heavy metals. TADF enables full exciton harvesting without such metals, offering a sustainable alternative. By providing a predictive framework for designing high-performance TADF emitters, this research accelerates the development of efficient, stable, and color-tunable OLED materials, contributing to more sustainable and advanced optoelectronic devices.
What are the key findings or observations of your doctoral research?
Our systematic computational screening identified promising candidates, with experimental results confirming predictions: e-2-1 and G13 achieved near-unity quantum yields, short excited-state lifetimes, and excellent thermal and photostability for TADF, while C5 exhibited bright phosphorescence.
Three quantitative computational metrics for designing high-performance TADF emitters were established: (1) minimized HOMO–LUMO overlap integral to reduce the singlet–triplet energy gap while retaining oscillator strength, (2) favorable triplet–singlet energy ordering, and (3) moderate dipole moment reorganization. Mechanistic insights were gained for deep-blue CMA emitters with enhanced radiative rates and phosphorescent carbene–metal–carboranyl complexes. Our research advances the understanding of TADF mechanism in organometallic systems and provides a validated computational framework that contributes to the discovery of efficient, stable, and color-pure OLED materials.
How can the results of your doctoral research be utilised in practice?
The results of my doctoral research provide a powerful computational framework that can be directly applied to the practical design and development of advanced OLED materials. By establishing clear, quantitative metrics for identifying high-performance TADF emitters, the research enables materials scientists to predict promising molecules before costly and time-consuming synthesis and experimental testing.
This predictive approach accelerates the discovery and optimization of OLED emitters that deliver high efficiency, excellent thermal and photostability, and tunable emission colors. The focus on carbene–metal–amide complexes offers a sustainable alternative to traditional heavy-metal-based phosphorescent materials, reducing reliance on scarce and expensive resources.
In industry, this framework supports the development of next-generation displays and lighting technologies that are more energy-efficient, longer-lasting, and capable of producing vibrant, color-pure light.
What are the key research methods and materials used in your doctoral research?
My research combined systematic computational and experimental methods to study carbene–metal–amide (CMA) complexes as TADF emitters for OLED devices. Density functional theory (DFT) and time-dependent DFT (TD-DFT) were employed to analyze over 130 CMA complexes, focusing on ligand variations and their effects on key photophysical properties such as HOMO–LUMO overlap integral, singlet–triplet energy gap, oscillator strength, and excitation dynamics. Promising candidates were identified through this computational screening. Selected complexes (e-2-1, C5, G13) were synthesized and fully characterized experimentally by collaborators in the University of Manchester.
This integrated approach validated the computational predictions and provided insights into TADF mechanisms. Besides, the computational framework was also extended to phosphorescent carbene–metal–carboranyl complexes, demonstrating broader applicability.
The doctoral dissertation of Thao Nguyen Le Phuoc, MSc, entitled Computational Design of Carbene–Metal–Amide Complexes: Structure–Property Relationships for Thermally Activated Delayed Fluorescence in OLED Applications will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus. The opponent will be Professor Daniel Escudero, Department of Chemistry, KU Leuven, and the custos will be Professor Mikko Linnolahti, University of Eastern Finland. Language of the public defence is English.
For more information, please contact:
Thao Nguyen Le Phuoc, [email protected], tel. 040 816 4574
