Ultrasonic spray coating of polyethylenimine (ethoxylated) as electron injection and transport layer for organic light emitting diodes: The influence of layer morphology and thickn... oleh Inge Verboven, Rachith Shanivarasanthe Nithyanandakumar, Melissa Van Landeghem, Hilde Pellaers, Bart Ruttens, Jan D'Haen, Koen Vandewal, Wim Deferme