Methyl or fluoro substituted poly(triarylamines) (PTAAs) are electron rich with diphenylamine as the the backbone and substituted phenyl as side chains. Substituted PTAAs are originally used as hole transport layer (HTL) materials in OLED/OFET devices to improve charge extractions. PTAA can also act as electron blocking layer to reduce the chances of electron–hole recombination and energy loss in electronic devices. Fluorinated PTAA, 1F-PTAA and 2F-PTAA, can effectively downshift of the HOMO levels of PTAA derivatives due to the electron deficiency of fluorine, resulting in an increase of?VOC?hence the power conversion efficiency (PCE) of the device.
