Low Voltage Operable Eco-Friendly Water-Induced LiOx Dielectric Based Organic Field Effect Transistor

In this letter, we report water-induced Lithium oxide (LiO
$_{\text {x}}{)}$
based Organic field effect transistors with operating voltage under −2 V which combine the advantages of the floating film transfer method by using water as a liquid substrate for a self-assembled poly [2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5di (thien-2-yl)thieno [3,2-b]-thiophene)] (DPP-DTT) semicond- ucting layer. The devices demonstrated maximum saturation mobility (
$\mu _{\text {max}}{)}$
of 0.184 cm
$^{{2}}\,\,\text{V}^{-{1}}$
sec
$^{-{1}}$
, average mobility (
$\mu _{\text {avg}}{)}$
of 0.14 (±0.035) cm
$^{{2}}\,\,\text{V}^{-{1}}$
sec
$^{-{1}}$
,
$\text{I}_{ \mathrm{\scriptscriptstyle ON}}/\text{I}_{ \mathrm{\scriptscriptstyle OFF}}$
ratio of
$\sim 10^{{4}}$
,and threshold voltage (
$\text{V}_{\text {TH}}{)}$
of
$\sim $
1.12 (±0.3) V. The devices exhibited a subthreshold swing of 186 (±15) mV/decade and a surface trap density (
$\text{N}_{\text {ss}}$
of 4.63 (±0.42)
$\times 10^{{12}}$
cm
$^{-{2}}$
.eV
$^{-{1}}$
. Deionized water is used for making the precursor solution of lithium oxide from lithium nitrate without using any toxic additive, making it low cost and eco-friendly synthesis. LiOx based dielectric processed at
$300 ^{\circ }\text {C}$
showed leakage current density of
${1}.{6} \times {10}\,\,^{-{8}}$
A/cm2 at 1 MV/cm and capacitance of 380 (±18) nF/cm2.