Channel length-dependent characterisations of organic thin-film transistors with solution processable gadolinium phthalocyanine derivatives

Abstract

Spin-coated 52-nm-thick films of newly synthesised gadolinium liquid crystalline bisphthalocyanine sandwich (GdPc 2 ) complexes with octyl chains non-peripheral positions have been successfully employed as active layers for bottom-gate organic field effect transistors having both short (5 μm) and long (20 μm) channels. The scaling down of the channel length (L) decreases the field effect mobility due to the increase in the contact resistance between the gold electrodes and the GdPc 2 semiconducting layer. Values of on-off ratio and sub-threshold voltage swing are higher nearly one order of magnitude for L = 5 μ m than those for L = 20 μm.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rare-earth based tetrapyrrolic sandwiches: chemistry, materials and applications

“…By using spin-coated films of a liquid crystalline bis(phthalocyaninato) lutetium complex Lu[(α-Oct) 8 Pc] 2 , Ray et al fabricated bottom gated OFET devices, which showed a hole mobility of 1.5 × 10 −3 cm 2 V −1 s −1 with an on/off current ratio of 10 3 at a threshold voltage of −25 V. 434 After thermal annealing, the hole mobility was improved to 8.0 × 10 −3 cm 2 V −1 s −1 , together with an increased on/off ratio by two orders of magnitude and a reduced threshold voltage to half of that of the as-deposited films. Recently, through the study of spin-coated films of the gadolinium complex Gd[(α-Oct) 8 Pc] 2 , 435 Ray et al revealed that the OFET performance decreases along with scaling down the channel length of devices. The electronic transport properties of drop-casted films of a triple-decker complex Tb 2 [(BuO) 8 Pc] 3 were reported by Yamashita et al , which also show p-type mobilities in the range of 1–2 × 10 −5 cm 2 V −1 s −1 .…”