The Effect of Transfer Printing on Pentacene Thin-Film Crystal Structure

TL;DR

This study investigates how transfer printing affects the crystal structure and quality of pentacene thin films, demonstrating improved film properties on flexible substrates for potential use in transistors.

Contribution

It provides new insights into the structural changes and phase transitions of pentacene films due to transfer printing, highlighting its benefits for flexible electronics.

Findings

Increased c-axis correlation length by 12-16% with transfer printing.

Observation of phase transition from 15.4 A to 14.4 A with film thickness.

Enhanced film quality on flexible substrates for transistor applications.

Abstract

The thermal deposition and transfer Printing method had been used to produce pentacene thin-films on SiO2/Si and plastic substrates (PMMA and PVP), respectively. X-ray diffraction patterns of pentacene thin films showed reflections associated with highly ordered polycrystalline films and a coexistence of two polymorph phases classified by their d-spacing, d(001): 14.4 and 15.4 A.The dependence of the c-axis correlation length and the phase fraction on the film thickness and printing temperature were measured. A transition from the 15.4 A phase towards 14.4 A phase was also observed with increasing film thickness. An increase in the c-axis correlation length of approximately 12% ~16% was observed for Pn films transfer printed onto a PMMA coated PET substrate at 100~120 C as compared to as-grown Pn films on SiO2/Si substrates. The transfer printing method is shown to be an attractive for the fabrication of pentacene thin-film transistors on flexible substrates partly because of the resulting improvement in the quality of the pentacene film.