Das Abhirup, Maity Krishnendu, Mallik Samik, Sadhukhan Riya, Banerjee Rajdeep, Samanta Suman Kalyan, Goswami Dipak K
Organic Electronics Laboratory, Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
Nanoscale. 2025 Jun 19;17(24):14805-14815. doi: 10.1039/d5nr00991j.
This study investigates how interface disorder affects the crystallization of conjugated polymer thin films and the subsequent impact on charge transport in organic field-effect transistors (OFETs). Conjugated polymers are vital in the fabrication of OFETs due to their ability to conduct charge carriers. However, structural disorder at the interfaces of these thin films can significantly disrupt the alignment and arrangement of the polymer chains, leading to irregular and unpredictable diffusion patterns. This disorganized structure impedes the efficient transfer of charge carriers, which is crucial for the optimal performance of OFETs. Our comprehensive analysis employs X-ray scattering methods to accurately determine the crystallization induced by interface disorder in isoindigo-BTBT films, resulting from surface and interface interactions in a non-destructive manner. Analysis of X-ray reflectivity (XRR)-derived electron density profiles reveals the stacking of polymer chains within the middle of the film, accompanied by disordered arrangements at both the air-polymer and polymer-substrate interfaces. To elucidate the origins of interface disorder, we used classical nucleation theory, thickness-dependent XRR studies, and statistical analysis of surface morphology at various annealing temperatures. Furthermore, fabricating bottom gate top contact OFETs revealed reduced field effect mobility with increased disorder. This highlights the need to address disorder at the polymer-substrate interface to improve charge transport efficiency in these devices. By understanding and mitigating the effects of disorder at the semiconductor-dielectric interface, we can enhance the performance of OFETs, paving the way for more reliable and efficient organic electronic devices.
本研究调查了界面无序如何影响共轭聚合物薄膜的结晶过程以及随后对有机场效应晶体管（OFET）中电荷传输的影响。共轭聚合物因其传导电荷载流子的能力，在OFET制造中至关重要。然而，这些薄膜界面处的结构无序会显著扰乱聚合物链的排列和取向，导致不规则且不可预测的扩散模式。这种无序结构阻碍了电荷载流子的有效传输，而这对于OFET的最佳性能至关重要。我们的综合分析采用X射线散射方法，以无损方式准确确定异靛蓝 - BTBT薄膜中由界面无序引起的结晶，这是由表面和界面相互作用导致的。对X射线反射率（XRR）得出的电子密度分布进行分析，揭示了薄膜中间聚合物链的堆积情况，同时在空气 - 聚合物和聚合物 - 衬底界面处存在无序排列。为了阐明界面无序的起源，我们使用了经典成核理论、与厚度相关的XRR研究以及在不同退火温度下对表面形态的统计分析。此外，制造底栅顶接触OFET表明，随着无序程度增加，场效应迁移率降低。这突出了需要解决聚合物 - 衬底界面处的无序问题，以提高这些器件中的电荷传输效率。通过理解和减轻半导体 - 电介质界面处无序的影响，我们可以提高OFET的性能，为更可靠、高效的有机电子器件铺平道路。
