A team including researchers from Osaka University has developed a new molecular emitter for organic light-emitting diodes (OLEDs). Using rational chemical design, the scientists were able to arrange the electron donors and acceptors into a ring called a “macrocycle”. The devices fabricated show better efficiencies compared to linear molecular emitters. The wheel-shaped molecule could potentially also be used for energy-efficient chemical sensors.
OLEDs are used in several modern displays. They efficiently convert electricity into light with carbon-based molecules with a so-called p-conjugation. This means single and double chemical bonds alternate, allowing for high electron mobility because they’re delocalized over large regions of the molecule. These molecules are typically long linear chains.
The research team led by professor Youhei Takeda designed and synthesized a macrocyclic OLED emitter, in which the molecule has a permanently bonded ring structure. The nanoscale cavities inside the rings can be designed to interact with target molecules to create efficient and selective chemical sensors. Possible future applications include the detection of chemical substances such as water molecules or gases, based on the modulation of light emitted when the target substance is present inside the cavity.