Controlling polymorphic transformations of pentacene crystal through solvent treatments: An experimental and theoretical study

Horng Long Cheng, Jr Wei Lin

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

A promising and simple method to control the crystal polymorphic transformations of insoluble pentacene through solvent treatments is developed to obtain superior films with stable polymorphs and enhanced intermolecular electronic coupling, as proven by X-ray diffraction, Raman and absorption spectroscopy, and quantum chemical calculations. The degree of polymorphic transformations within films can be managed by the selection of appropriate organic solvents according to the magnitude of the pentacene-solvent interaction. A reaction pathway that could interpret how a metastable polymorph T ("thin film" phase) transforms into a more stable polymorph B ("bulk" or "single-crystal" phase) is proposed. The hypothesis is based on the terms of crystal structural parameters, including separation distance, tile angle, and herringbone edge-to-face angle. With the aid of quantum chemical calculations, we combine the binding energy of pentacene dimers and pentacene-solvent interaction energy to develop a new quantitative criterion for the selection of appropriate organic solvents for the structural improvement of organic crystal/films rather than damage. The proposed solvent post-treatments concepts could provide opportunities for improved vacuum-evaporated organic crystal/films and further expand potential applications in organic electronics and photonics.

Original languageEnglish
Pages (from-to)4501-4508
Number of pages8
JournalCrystal Growth and Design
Volume10
Issue number10
DOIs
Publication statusPublished - 2010 Oct 6

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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