Abstract
Spin-coated 52-nm-thick films of newly synthesised gadolinium liquid crystalline bisphthalocyanine sandwich (GdPc2) 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,upmu {text{m}}) and long ( 20,upmu {text{m}}) 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 GdPc2 semiconducting layer. Values of on–off ratio and sub-threshold voltage swing are higher nearly one order of magnitude for L = 5 ,upmu{text{ m}} than those for L = 20;upmu m.
Highlights
Lanthanide bisphthalocyanine sandwich compounds (LnPc2) in which the large conjugated π systems are held in close proximity by rare-earth ions, are characterised by their free radical character, facilitating electron transfer from one molecule to another in the solid state
Studies on chemichromic interactions between lutetium bis-octaalkylsubstituted phthalocyanines and biological cofactors namely nicotinamide adenine dinucleotide and l-ascorbic acid of concentrations ranging from 3.5 mM down to 0.03 mM can be adapted for developing practical devices in plasma, serum, red cells, urine and other accessible tissues for biochemical and functional status [8]
This paper reports the room temperature characteristic parameters of bottom-gate, bottom-contact organic thinfilm transistors (OTFTs) for two channel lengths L L = 5μm and L = 20μm using 52nm thick solution processed films of a novel liquid crystalline gadolinium bisphthalocyanine complex(8GdPc2) in Fig. 1, bearing a total of 16 octyl chains (R = C8H17) as substituents on its non-peripheral 1,4,8,11,15,18,22,25-positions
Summary
Lanthanide bisphthalocyanine sandwich compounds (LnPc2) in which the large conjugated π systems are held in close proximity by rare-earth ions, are characterised by their free radical character, facilitating electron transfer from one molecule to another in the solid state. These thermally stable, environmentally friendly and non-toxic compounds exhibit high intrinsic conductivities, small activation energy and large electronic affinity compared to those of monophthalocyanines [1] and have attracted great attention because of their potential applications in molecular electronics [2], organic field effect transistors (OTFTs) [3], molecular optronics [4], molecular iono-electronics [5] and chemical sensors [6]. Electrochemical and spectroelectro-chemical responses of the complexes to the π–π interaction are found
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