Synthesis and Performance of Polyimide Films for the Flexible Organic Light Emitting Diodes

A series of polyimide (PI) and copolyimide (Co-PI) films were prepared by two-step imidization processes from the poly(amicacid) precursors. The color and visible light transmission of the Co-PI films were much better than those of the general Kapton type PI film mainly due to the decrease of the charge transfer complex formation by the presence of the CF(3) groups both in the aromatic diamine and dianhydride monomers. In the ITO thin film deposition and subsequent OLED device fabrication, the thermal and mechanical properties of the Co-PI films were more important than the optical property of the Co-PI filmsclose2