[Abstract]

Organic field-effect transistors (OFETs) are promising for numerous potential applications but suffer from poor charge injection, such that their performance is severely limited. Recent efforts in lowering contact resistance have led to significantly improved field-effect mobility of OFETs, up to 100 times higher, as the results of careful choice of contact materials and/or chemical treatment of contact electrodes. Here we review the innovative developments of contact engineering and focus on the mechanisms behind them. Further improvement toward Ohmic contact can be expected along with the rapid advance in material research, which will also benefit other organic and electronic devices.