Masters Robert C, Stehling Nicola, Abrams Kerry J, Kumar Vikas, Azzolini Martina, Pugno Nicola M, Dapor Maurizio, Huber Andreas, Schäfer Philip, Lidzey David G, Rodenburg Cornelia
Department of Materials Science and Engineering University of Sheffield Sheffield S1 3JD UK.
European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT-FBK) and Trento Institute for Fundamental Physics and Applications (TIFPA-INFN) Trento 38123 Italy.
Adv Sci (Weinh). 2019 Jan 20;6(5):1801752. doi: 10.1002/advs.201801752. eCollection 2019 Mar 6.
Understanding nanoscale molecular order within organic electronic materials is a crucial factor in building better organic electronic devices. At present, techniques capable of imaging molecular order within a polymer are limited in resolution, accuracy, and accessibility. In this work, presented are secondary electron (SE) spectroscopy and secondary electron hyperspectral imaging, which make an exciting alternative approach to probing molecular ordering in poly(3-hexylthiophene) (P3HT) with scanning electron microscope-enabled resolution. It is demonstrated that the crystalline content of a P3HT film is reflected by its SE energy spectrum, both empirically and through correlation with nano-Fourier-transform infrared spectroscopy, an innovative technique for exploring nanoscale chemistry. The origin of SE spectral features is investigated using both experimental and modeling approaches, and it is found that the different electronic properties of amorphous and crystalline P3HT result in SE emission with different energy distributions. This effect is exploited by acquiring hyperspectral SE images of different P3HT films to explore localized molecular orientation. Machine learning techniques are used to accurately identify and map the crystalline content of the film, demonstrating the power of an exciting characterization technique.
了解有机电子材料中的纳米级分子排列是制造更好的有机电子器件的关键因素。目前，能够对聚合物中的分子排列进行成像的技术在分辨率、准确性和可及性方面都受到限制。在这项工作中，我们展示了二次电子（SE）光谱和二次电子高光谱成像技术，它们为利用扫描电子显微镜的分辨率探测聚（3-己基噻吩）（P3HT）中的分子排列提供了一种令人兴奋的替代方法。实验表明，P3HT薄膜的结晶含量通过其SE能谱反映出来，这在经验上以及通过与纳米傅里叶变换红外光谱（一种探索纳米级化学的创新技术）的相关性都得到了验证。我们使用实验和建模方法研究了SE光谱特征的起源，发现非晶态和晶态P3HT的不同电子性质导致了具有不同能量分布的SE发射。通过获取不同P3HT薄膜的高光谱SE图像来利用这种效应，以探索局部分子取向。机器学习技术被用于准确识别和绘制薄膜的结晶含量，展示了这种令人兴奋的表征技术的强大功能。
