Lithium Perchlorate-Doped Poly(sty rene-b-ethylene oxide-b-styrene)Lamellae-Forming Triblock Copolymer as High Capacitance,Smooth,Thin Film Dielectric

摘要

A symmetric poly(styrene-b-ethylene oxide-b-styrene)(SOS)triblock copolymer with block molecular weights(M_n)of 7k-14k-7k was synthesized by anionic polymerization.Various amounts of lithium perchlorate salt([O/Li] = 3,6,12,24,and 48)were incorporated into the SOS block copolymer to achieve an elevated charge carrier density,which also led to lamellae formation and reduced crystallinity of the poly(ethylene oxide)block according to small-angle X-ray scattering and differential scanning calorimetry.Spin-coated SOS/LiClO4 capacitors of 30 nm thickness exhibit very high capacitances(up to 4.5 mu F/cm~2 at 10 Hz and 1.5 mu F/cm~2 at 1000 Hz with an amplitude of 0.1 V)and rather smooth surfaces(root-mean-square roughness of 0.5-2 nm).We expect to optimize these thin-film capacitors for high-performance organic thin film transistor applications.