Solvent Vapor Annealing in the Molecular Regime Drastically Improves Carrier Transport in Small-Molecule Thin-Film Transistors
详细信息 查看全文
- 作者：Hadayat Ullah Khan ; Ruipeng Li ; Yi Ren ; Long Chen ; Marcia M. Payne ; Unnat S. Bhansali ; Detlef-M. Smilgies ; John E. Anthony ; Aram Amassian
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2013
- 出版时间：April 10, 2013
- 年：2013
- 卷：5
- 期：7
- 页码：2325-2330
- 全文大小：354K
- 年卷期：v.5,no.7(April 10, 2013)
- ISSN：1944-8252
文摘
We demonstrate a new way to investigate and control the solvent vapor annealing of solution-cast organic semiconductor thin films. Solvent vapor annealing of spin-cast films of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) is investigated in situ using quartz crystal microbalance with dissipation (QCM-D) capability, allowing us to monitor both solvent mass uptake and changes in the mechanical rigidity of the film. Using time-resolved grazing incidence wide angle X-ray scattering (GIWAXS) and complementary static atomic force microscopy (AFM), we demonstrate that solvent vapor annealing in the molecular regime can cause significant performance improvements in organic thin film transistors (OTFTs), whereas allowing the solvent to percolate and form a liquid phase results in catastrophic reorganization and dewetting of the film, making the process counterproductive. Using these lessons we devise processing conditions which prevent percolation of the adsorbed solvent vapor molecules for extended periods, thus extending the benefits of solvent vapor annealing and improving carrier mobility by nearly two orders of magnitude. Ultimately, it is demonstrated that QCM-D is a very powerful sensor of the state of the adsorbed solvent as well as the thin film, thus making it suitable for process development as well as in-line process monitoring both in laboratory and in future manufacturing settings.