Structural characteristics of thermally advanced polymer with intrinsic microporosity for application as flexible OLED substrate

The chemical and structural characteristics of solution-processed polymer with intrinsic microporosity (PIM) based on 9, 9-bis (4-hydroxyphenyl) fluorene (BHPF) film is investigated. A fully flexible and transparent PIM film exhibiting uniform and high transmittance of more than 90% within the visible light range is demonstrated. The stability of the PIM film is further demonstrated with relatively stable coefficient of thermal expansion (CTE) characteristics. Additionally, the film has high heat resistance that can withstand high-temperature processes at 250 °C. The PIM film exhibits a remarkably high glass transition temperature (Tg) of 294.7 °C, indicating the thermal stability of the film at elevated temperatures. The PIM film also exhibits relatively high surface energy, low surface roughness (Rq), and peak-to-valley values of 0.45 and 4.4 nm, respectively. This surface morphology confirms the PIM film's superior characteristic in preventing short circuits or leakage in current paths in an organic electronic device. Finally, the PIM film is successfully tested as a substrate for a bottom-emitting organic light-emitting diode (OLED). The investigation has proven PIM film to be a good candidate to be adopted as a substrate in fabricating advanced organic electronic devices and next-generation displays.