Investigation of the Performance of Donor-Acceptor Conjugated Polymers in Electrolyte-Gated Organic Field-Effect Transistors

Electrolyte-gated organic field-effect transistors (EGOFETs) are low-power thin-film electronic device that is gaining interest for application in healthcare and environmental science. However, robust performance in terms of charge-carrier mobility, on-to-off drain current ratio, and turn-on speed are required for real application. Here, donor-acceptor (D-A) conjugated polymers, namely poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (PDPPDTT) and indacenodithiophene-co-benzothiadiazole (PIDTBT), are evaluated in EGOFETs. The operational performance of these materials is compared to that of the well-established liquid crystalline poly[2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT). The effective mobility extracted for the PDPPDTT (0.18 cm2.V-1.s-1), and PIDTBT (0.16 cm2.V-1.s-1) devices was almost double that of the PBTTT (0.10 cm2.V-1.s-1) based device and the on-to-off current ratio was one ((PDPPDTT): 3 × 103) or two ((PIDTBT): 2 × 104) order of magnitude higher than that of PBTTT (2 × 102) devices. The extracted values compare favourably to those of the highest performing EGOFETs presented in the literature and EGOFETs based on the D-A polymers turn from off to on state two to ten times faster the analogous PBTTT device with an improved subthreshold swing. These results show that D-A polymers with a planar conjugated backbone enable the development of robust EGOFETs that are well appropriate for applications in bioelectronic and environmental science.