Understanding the drastic solvent resistance change in semi-crystalline polymer semiconductors upon thermal annealing

Thermal annealing is widely known to improve the performance of organic semiconductor devices due to effects such as defect healing, side-chain reorientation/ crystallization etc. However, its effect on thin film dissolution has not yet been investigated. In our study of several polymer semiconductors, we find that most materials exhibit a change in solvent after heating above a certain temperature. The location and width of the temperature window where this solvent resistance change occurs is different for different polymer semiconductors. With this experiment, we aim to investigate technologically relevant polymers in this material-specific temperature range and obtain important information on the changes in the crystalline phase. This data will complement other experimental data and help to draw a comprehensive picture of the changes in the semi-crystalline thin film morphology that leads to the drastic changes in the dissolution behavior upon thermal post-treatments.