Thermal Sensing Characteristics of Low-Voltage n-Channel Organic Field-Effect Transistors With Triple Layers of Naphthalenediimide-Containing Conjugated Polymer and Gate-Insulating Polymers

Organic field-effect transistors (OFETs) were fabricated with n-type naphthalenediimide-based conjugated polymer (N2200) as a channel layer and poly(methyl methacrylate) (PMMA)/poly(vinyl alcohol) (PVA) as a gate-insulating layer. The OFETs with the N2200/PMMA/PVA triple layers were operated with an n-channel mode at low voltages (≤5 V) and their electron mobility reached ca. 0.63 cm2/
$\text{V}\cdot \text{s}$
at a drain voltage of 5 V. The drain current of OFETs was gradually increased as the temperature of channel region increased from 25 °C to 80 °C, whereas no shift in threshold voltage was measured upon the temperature variation. The relative thermal sensitivity of devices was almost linearly increased with the temperature, while a two-stage behavior by a border of ca. 35 °C was measured for specific thermal sensitivity. The present n-channel OFETs exhibited excellent thermal sensing performances upon repeated approaching/retracting tests using a heat source.