大久助教と、卒業生各務彰君（2016年３月修卒）のリンモリブデン酸正孔注入層に関する論文、「A Solution-Processed Heteropoly Acid Containing MoO3 units as a Hole-Injection Material for Highly Stable Organic Light-Emitting Devices」が、アメリカ化学会(ACS) の ACS Applied Materials & Interfaces (IF: 7.145) にアクセプトされました。大久先生、各務、おめでとうございます！
By S. Ohisa, S. Kagami, Y.-J. Pu, T. Chiba, J.Kido
Abstract: We report hole-injection layers (HILs) comprising a heteropoly acid containing MoO3units, phosphomolybdic acid (PMA), in organic light-emitting devices (OLEDs). PMA possesses outstanding properties, such as high solubility in organic solvents, very low surface roughness in the film state, high transparency in the visible region, and an appropriate work function (WF), that make it suitable for HILs. We also found that these properties were dependent on the post-baking atmosphere and temperature after film formation. When the PMA film was baked in N2, the Mo in the PMA was reduced to Mo(V), whereas baking in air had no influence on the Mo valence state. Consequently, different baking atmospheres yielded different WF values. OLEDs with PMA HILs were fabricated and evaluated. OLEDs with PMA baked under appropriate conditions exhibited comparably low driving voltages and higher driving stability compared with OLEDs employing conventional hole-injection materials (HIMs), poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate), and evaporated MoO3, which clearly shows the high suitability of PMA HILs for OLEDs. PMA is also a commercially available and very cheap material, leading to the widespread use of PMA as a standard HIM.
