Surface Viscoelasticity of an Organic Interlayer Affects the Crystalline Nanostructure of an Organic Semiconductor and Its Electrical Performance

详细信息    查看全文

• 作者：Hwa Sung Lee ; Moon Sung Kang ; Sung Kyung Kang ; Beom Joon Kim ; Youngjae Yoo ; Ho Sun Lim ; Soong Ho Um ; Du Yeol Ryu ; Dong Ryeol Lee ; Jeong Ho Cho
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：October 18, 2012
• 年：2012
• 卷：116
• 期：41
• 页码：21673-21678
• 全文大小：413K
• 年卷期：v.116,no.41(October 18, 2012)
• ISSN：1932-7455

文摘

We demonstrated that the viscoelasticity of a dielectric surface affected the overlying pentacene crystalline nanostructures and the electrical performances of pentacene-based field-effect transistors (FETs). The surface viscoelasticities of the gate dielectrics were systematically controlled by varying the polymer chain lengths of polystyrene brushes (b-PSs) and the substrate temperature during pentacene deposition. The b-PSs were chosen as a model surface because the glass鈥搇iquid transition affected neither the surface energy nor the surface roughness. Moreover, the glass鈥搇iquid transition temperature increased with increasing b-PS chain length. The liquid-like b-PS chains disturbed the surface arrangement of the pentacene molecules, which reduced the organization of the crystalline structures, yielding smaller grains during the early stages of pentacene growth. The dramatic changes in the film morphology and crystalline nanostructures above the b-PS glass鈥搇iquid transition resulted in noticeable changes in the OFET performance. The systematic investigation of the dielectric surface viscoelasticity presented here provides a significant step toward optimizing the nanostructures of organic semiconductors, and thereby, the device performance, by engineering the interfaces in the OFETs.