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Innovative application of modified AZABODIPY molecules in near-infrared emitting OLEDs: perspectives for sustainable development

PhD Wojciech Mróz – Graduated from the Faculty of Technical Physics and Applied Mathematics at the Gdańsk University of Technology. He has worked scientifically for the University of Milan-Bicocca, the University of Milan, the Italian National Research Council and the Italian Institute of Technology. Currently, he is an independent researcher at the Institute of Chemical Sciences and Technologies “Giulio Natta” in Milan. His research activity focuses on the production and characterization of electroluminescent diodes based on conjugated organic semiconductors (molecules, metal complexes, polymers), as well as perovskites, prepared mainly, but not only, from solutions. Part of his work is also dedicated to the photophysical characterization of materials used in optoelectronic devices. The aim of his research is to understand the processes occurring in these systems and to find ways to improve them, with the ultimate goal of application in industrial prototypes.

OLED (Organic Light Emitting Diode)

In the face of the growing need for sustainable development, innovations in OLED (Organic Light-Emitting Diode) technology are becoming a significant factor in shaping the future of lighting systems and displays. Through research on new light-emitting materials, scientists are opening doors to new possibilities in terms of efficiency and ecological solutions, heralding another important step in the evolution of display technology.

In the latest measurements conducted by an international team of scientists involving Dr. Wojciech Mróz (Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche), the potential of a new light-emitting molecule in the near-infrared (NIR) range was investigated, which may delineate another promising path for OLED technology. The team focused on the analysis of a derivative of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY), modified by adding nitrogen in the meso position, creating a structure known as AZABODIPY [FIGURE 1]. Phenyl and thiophene groups were attached to this molecule (DTDPAB), resulting in a reduction in the energy of emitted photons. The results, published in the journal “Materials Advances,” indicate promising properties of this material in electroluminescent applications. 

Figure 1. Structures of BODIPY, AZABODIPY, and DTDPAB molecules. The figure taken from Materials Advances 2023, 4, 1702 under CC-BY license.

As the scientists say: “The research results pave the way for the application of AZABODIPY derivatives as NIR electroluminescent emitters. Furthermore, the approach introduced in this work may be an important suggestion for further research on other, already known, materials that could exhibit similar behavior.”

Advanced modifications of AZABODIPY enable electroluminescence in the infrared range

Stabilization of the LUMO state by introducing nitrogen into the BODIPY structure leads to a significant reduction in the energy gap in the resulting AZABODIPY molecule. Another modification, such as adding thiophene groups, increases the HOMO level, allowing for further reduction in the energy gap. Due to the tendency of the AZABODIPY molecule and its derivative DTDPAB to the  aggregates formation, their emission shifts towards the infrared again. All these changes in the molecule’s structure and emitter organization in the OLED layer enabled the achievement of emission in the pure infrared with a maximum at 910 nm [Figure 2], which is a breakthrough in the field of electroluminescence using an emitter based on AZABODIPY.

Figure 2: Electroluminescence spectrum of the diode with DTDPAB molecule employed as emitter. The figure taken from Materials Advances 2023, 4, 1702 under CC-BY license.

Significance of the research for OLED technology development

The significance of this discovery goes beyond purely scientific aspects, opening up new possibilities in the context of sustainable development. The use of DTDPAB in OLED technology enables the production of devices emitting light in the NIR range, which may contribute to reducing dependence on rare earth elements, typically used for emission generation in this spectral range. The quantity of these materials is limited, they are unevenly distributed worldwide, and their extraction is energetically and environmentally costly, making the application of organic electroluminescent materials an important step towards environmentally friendly and technologically efficient solutions.

Research on AZABODIPY derivatives also opens up new perspectives for future innovations in the field of NIR screens and specialized lighting systems. Further research will focus on optimizing this molecule in various polymer matrices, which can significantly impact the efficiency and durability of OLED devices. Scientists also plan to investigate how different structural modifications will affect electroluminescent properties, which may pave the way for creating more complex and specialized applications.

This discovery not only expands the boundaries of knowledge in the field of NIR electroluminescence but also represents a potential paradigm shift in the production and design of future electroluminescent devices. The collaboration of the team with Dr. Mroz constitutes a significant step towards the realization of more sustainable lighting technologies, which will not only be efficient but also environmentally friendly. In light of these results, the future of OLED technology appears particularly promising, with doors open to further research and development in this dynamically evolving field.

Fot. Unsplash

Jakub Kalbarczyk
Wojciech Mroz
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