Phospholipid film in electrolyte-gated organic field-effect transistors

A totally innovative electrolyte-gated field effect transistor, embedding a phospholipid film at the interface between the organic semiconductor and the gating solution, is described. The electronic properties of OFETs including a phospholipid film are studied in both pure water and in an electrolyte solution and compared to those of an OFET with the organic semiconductor directly in contact with the gating solution. In addition, to investigate the role of the lipid layers in the charge polarization process and quantify the field-effect mobility, impedance spectroscopy was employed. The results indicate that the integration of the biological film minimizes the penetration of ions into the organic semiconductor thus leading to a capacitive operational mode as opposed to an electrochemical one. The OFETs operate at low voltages with a field-effect mobility in the 10−3 cm2 V−1 s−1 range and an on/off current ratio of 103. This achievement opens perspectives to the development of FET biosensors potentially capable to operate in direct contact with physiological fluids.

An electrolyte-gated OFET including a phospholipid film at the interface between the organic semiconductor and an ionic gating solution is described. The phospholipid (PL) layer, acting as an efficient barrier towards ionic diffusion into the organic semiconductor, allows to achieve a largely capacitive gating of the OFET even in the presence of an ionic solution. The PL–OFET on/off ratio in excess of 103 opens perspectives to the development of FET biosensors operating with physiological fluids.Figure optionsDownload as PowerPoint slideHighlights
► An electrolyte-gated OFET embedding a lipid film is proposed.
► The OFETs operate at low voltages in water and in electrolyte solutions.
► The P3HT doping is minimized achieving a capacitive operational mode.
► New perspectives to the biosensor development working in water.