Pentacene-based organic thin-film transistors have been fabricated using a phosphonate-linked anthracene self-assembled monolayer as a buffer between the silicon dioxide gate dielectric and the active pentacene channel region. Vast improvements in the subthreshold slope and threshold voltage are observed compared to control devices fabricated without the buffer. Both observations are consistent with a greatly reduced density of charge trapping states at the semiconductor-dielectric interface effected by introduction of the self-assembled monolayer.

Organic thin-film transistors using pentacene as the semiconductor were fabricated on silicon. A series of phosphonate-based self-assembled monolayers (SAMs) was used as a buffer between the silicon dioxide gate dielectric and the active pentacene channel region. Octadecylphosphonate, (quarterthiophene)phosphonate, and (9-anthracene)phosphonate SAMs were examined. Significant improvements in the sub-threshold slope and threshold voltage were observed for each SAM treatment as compared to control devices fabricated without the buffer. These improvements were related to structural motif relationships between the pentacene semiconductor and the SAM constituents. Measured transistor properties were consistent with a reduction in density of charge trapping states at the semiconductor-dielectric interface that was effected by introduction of the self-assembled monolayer.

The alignment of molecular energy levels between a self-assembled monolayer of 9-phosphonoanthracene formed on silicon dioxide and pentacene has been studied using photoelectron spectroscopies. The semiconducting band gap of pentacene was found to be nested within that of the monolayer, resulting in a 1.3± 0.1 eV barrier for hole injection from pentacene into the monolayer. The corresponding barrier to electrons, estimated from the adiabatic highest occupied molecular orbital/ lowest unoccupied molecular orbital gaps of anthracene and pentacene, is 0.3± 0.2 eV. Thus, the monolayer presents a significant energetic barrier to hole injection from a pentacene overlayer, but only a small to moderate barrier to electrons.

Infinite Power Solutions manufactures a flexible rechargeable micro ampere-hour solidstate battery based on thin-film Lithium technology where the battery can be engineered into the product for life as a cost effective solution with “the battery that never needs to be replaced”. The performance characteristics of the battery combined with low power electronic textile applications will require “A Different Way of Thinking About Batteries” relative to battery management and innovative methods of recharging the battery (such as charging the battery whenever the materials are washed and dryed). This paper will review the characteristics of the battery specifically in relation to power generation for flexible electronic materials and the integration issues for a thin-film battery for flexible electronic materials.