company news about Progress in UV-OLED Research

          Progress in UV-OLED Research

  Ultraviolet (UV) light plays a key role in the development of photochemistry and photocatalysis. Currently, the main means of achieving UV light include toxic mercury lamps and light-emitting diodes (LEDs). In contrast, organic light-emitting diodes (OLEDs) are regarded as a new generation of display and lighting technology due to their thinness, flexibility, low power consumption and high contrast, and are expected to become a new carrier of UV light sources.

  However, the wide bandgap characteristics of short-wavelength organic light-emitting materials increase the difficulty of carrier injection and recombination during their electroluminescence. At present, there is still a lack of effective molecular design strategies to balance the light color and exciton dynamics of short-wavelength organic light-emitting materials. How to achieve high-efficiency, high ultraviolet light share and high brightness UV-OLEDs is still a huge challenge.

  Recently, based on the "crossed long-short axis" (CLSA) molecular design strategy, the research group of researcher Wang Zhiming used meta-linking to further shorten the degree of conjugation and designed an ultraviolet material m-Cz that can effectively inhibit the red shift of aggregation. The non-doped device based on m-Cz achieved ultraviolet light emission with a peak emission of 382 nm, a maximum external quantum efficiency of 8.3%, and a UV400 of 59.6%, which is currently the most efficient non-doped UV-OLED.

  The CLSA strategy is a molecular design strategy for constructing high-performance short-wavelength light-emitting materials. It separates carrier injection and exciton radiation by constructing a nearly perpendicular twist angle between the short molecular axis dominated by the charge transfer (CT) state and the long molecular axis dominated by the localized state. The long molecular axis composed of luminescent groups ensures a high photoluminescence external quantum efficiency (PLQY), while the donor-acceptor structure of the short axis can improve carrier injection and transmission. The high-energy CT state helps to open the hot exciton channel and achieve higher exciton utilization.