Effects of Annealing and Residual Solvents on Amorphous P3HT and PBTTT Films
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- 作者：Domenico Alberga ; Giuseppe Felice Mangiatordi ; Luisa Torsi ; Gianluca Lattanzi
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：April 24, 2014
- 年：2014
- 卷：118
- 期：16
- 页码：8641-8655
- 全文大小：805K
- 年卷期：v.118,no.16(April 24, 2014)
- ISSN：1932-7455
文摘
Organic thin film transistors (OTFT) are metal鈥搃nsulator鈥搒emiconductor field-effect transistors in which the semiconductor is a conjugated organic material. They are the subject of intense industrial research because their fabrication process is less expensive when compared with inorganic TFTs. Among the others, the organic material mostly employed in their construction consists of two semiconductor polymers, namely poly(3-hexylthiophene) (P3HT) and poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT). Despite the large amount of experimental efforts in the characterization of the electronic properties of these devices, several questions regarding their morphological arrangement in bulk and at interfaces remain wide open. Here, we report results obtained by classical molecular dynamics simulations of P3HT and PBTTT inspired by OTFT fabrication techniques. In particular, we investigate how the annealing fabrication process and the presence of residual solvent molecules left over after spin coating might modify the morphology and the dynamics of the amorphous phase of these two polymers. Simulations of both polymer deposits at 300 K after annealing show an increase in the number of interdigitation events between the alkyl chains of two polymeric macromolecules; moreover, we find that the increased stability of the 蟺鈥撓€ stacking is caused by an improved layering of the films, which may account for the better charge transport properties reported in experiments. Our results strongly suggest that thin semiconductor films are required to boost the performances of the devices and that a minimal presence of residual solvent does not alter dramatically the microscopic structure and stability of the polymeric films.