大久助教の論文が ACS Applied Materials & Interfaces に受理されました。大久先生、おめでとうございます!
Abstract
In organic light emitting devices (OLEDs), interfacial structures between multilayers have large impacts on the characteristics of OLEDs. Herein, we succeeded in revealing the interdiffusion in solution processed and thermal annealed OLEDs by neutron reflectometry (NR). We investigated interfaces between a polymer under layer and small molecules upper layer. The small molecules diffused into the swollen polymer layer during the interfacial formation by the solution process, but the polymer did not diffuse into the small molecules layer. At temperatures close to the glass transition temperatures (Tg) of the materials, asymmetric molecular diffusion was observed. We elucidated the effects of the interdiffusion on the characteristics of OLEDs. Partially mixing the interface improved the current efficiencies, due to suppressed triplet-polaron quenching in the interface. Controlling and understanding the interfacial structures of the miultilayers will be more important to improve the OLED characteristics.