Dual-action molecule debuts, revolutionizing OLED screens and sophisticated medical visualization.
In a groundbreaking development, researchers at Kyushu University have created a single organic molecule, CzTRZCN, that can excel in both light emission for OLEDs and light absorption for deep-tissue imaging [1][2][4][5]. This molecular "switch" toggles between two functional states, optimized for emitting and absorbing light, respectively.
The switching capability of CzTRZCN is due to its ability to rearrange its electron orbital configurations based on its role. For light emission, it adopts a twisted structure with separated electron orbitals, enabling efficient thermally activated delayed fluorescence (TADF) [2][4][5]. TADF converts energy trapped in a non-light-emitting triplet state into a light-emitting singlet state using heat, thereby enhancing brightness and energy efficiency.
On the other hand, for light absorption, CzTRZCN transitions into a more planar structure with overlapping electron orbitals, suitable for two-photon absorption (2PA) [2][4][5]. This mechanism allows the molecule to absorb two lower-energy photons simultaneously, usually near-infrared, minimizing cellular damage and enabling high-precision imaging deep within biological tissues.
The structure of CzTRZCN is engineered by combining an electron-rich carbazole (Cz) unit with an electron-deficient triazine (TRZ) core, and adding cyano (CN) groups to finely tune the electron distribution and orbital arrangement [2][4][5]. This design enables the molecule to switch between the twisted orbital arrangement for TADF and the planar arrangement for 2PA, bridging two previously incompatible functions in one compound.
In an OLED device, CzTRZCN reached an external quantum efficiency of 13.5%, a record for triazine-based TADF materials [5]. The lead researcher, Youhei Chitose, noted that the molecule's metal-free, low-toxicity nature makes it highly biocompatible, ideal for medical probes [5]. Time-resolved fluorescence microscopy could particularly benefit from the material's performance, and the work bridges photoelectronics and bioimaging, opening doors for devices that seamlessly cross between consumer electronics and healthcare.
In medicine, the molecule uses 2PA to allow absorption of two lower-energy photons at once, reducing scattering and damage in deep-tissue imaging [1]. The new molecule also showed a high 2PA cross-section and strong brightness, making it promising for medical imaging [1]. The study outlines a strategy for creating molecules with different orbital arrangements for light absorption and emission, potentially inspiring new multifunctional materials.
This discovery could pave the way for devices that bridge entertainment and healthcare, using one molecule to power brighter displays and enable safer, sharper diagnostics. The potential applications include in vivo imaging, wearable sensors, and next-generation OLED displays, as the team plans to expand the design to cover more emission wavelengths and collaborate with biomedical and device engineers [1].
[1] https://www.kyushu-u.ac.jp/en/news/2021/09/27-1/ [2] https://pubs.acs.org/doi/10.1021/acsami.1c15684 [4] https://pubs.rsc.org/en/content/articlelanding/2021/an/d1an00258c [5] https://www.nature.com/articles/s41598-021-99850-0
The revolutionary molecule, CzTRZCN, demonstrates its potential in both science and technology, showcasing its ability to excel in both light emission for OLEDs and light absorption for deep-tissue imaging, a feat often associated with separate compounds. This innovation in robotics, engineering a single molecule to perform two previously incompatible functions, offers exciting possibilities in the realms of science and technology.
