Detailed Investigation of Plasticized PMMA Dielectric for Improved Performance of Organic Field-Effect Transistors

Abstract

In this study, organic field-effect transistors (OFETs) were fabricated using plasticized poly(methyl methacrylate) (PMMA) as the gate dielectric and copper phthalocyanine (CuPc) as the active layer. Propylene carbonate (PC) was used as a plasticizer material. The dielectric properties of the plasticized PMMA were investigated in detail and the OFET parameters were examined. The effective capacitance (Ci) of plasticized PMMA was measured as ~ 500 nF cm−2 (at 100 Hz), which is almost 70 times higher than that of pure PMMA. This increase in effective capacitance led to significant improvements in various key parameters of the fabricated OFETs. High hole field-effect mobility values (0.81 cm2 V−1 s−1), low threshold voltages (~ ±0.1 V), and low operating voltages (0 to ±0.8 V) were achieved by using the plasticized PMMA dielectric. The temperature dependence of the fabricated OFETs was also investigated, and the activation energy of CuPc was estimated as 29.3 meV. The plasticized OFETs demonstrated excellent stability over 3600 measurement cycles carried out in an ambient atmosphere. This demonstrated stability of the fabricated OFETs reinforces the practical feasibility of this material combination strategy, positioning it as a key advancement in the field of solution-processable gate dielectrics.