晶片式相位板搭配穿透式電子顯微鏡技術應用於軟物質材料之觀測

Abstract

穿透式電子顯微鏡﹙Transmission Electron Microscopy, TEM﹚顯像術，於材料科學領域中已是被廣泛應用於奈米結構觀測及分析的工具。然而，其於觀測軟物質材料之應用，卻因為此類材料於穿透式電子顯微鏡影像中的低對比特性，而受到限制。配合穿透式電子顯微鏡之相位板技術已經發展了數十年，但由於影像品質相較未使用相位板時劣化過多，使用者無法以其取得影像品質穩定的準焦﹙in-focus﹚影像，因而此技術仍然無法被實際應用於材料科學研究上。 在本論文的研究中，實現了晶片式相位版的設計，有效地提高電荷傳導效率，解決了電荷累積效應﹙charging effect﹚，並將其實際應用於軟物質材料的研究上，提高此類材料之穿透式電子顯微鏡影像對比，且能穩定取得準焦影像。 本研究以此穩定的晶片式相位板搭配穿透式電子顯微鏡技術，於不同製程條件的有機太陽能電池元件中，首次觀察並驗證了奈米顆粒相的存在。 在本研究中，也利用此系統取得未染色之大腸桿菌﹙E. coli﹚樣品之穿透式電子顯微鏡影像，於影像中解析樣品細部結構並驗證影像對比提升之作用。 本論文的研究成功將晶片式相位板結合穿透式電子顯微鏡系統，發展提升影像對比之準焦穿透式電子顯微術，對於軟物質材料的研究領域將有極大的助益。

Transmission electron microscopy (TEM) is a powerful tool in imaging nanostructures, yet its capability is limited with respect to the imaging of soft materials, because of the intrinsic low contrast problem. TEM phase plates have been in development for decades, yet a reliable phase plate technique has not been available because the performance of TEM phase plates deteriorates too quickly. Such an obstacle prohibits in-focus TEM phase imaging to be routinely achievable, thus limits the technique being used in practical applications. Here we present an on-chip thin film Zernike phase plate which can effectively release charging, and allow reliable in-focus TEM images of soft materials with enhanced contrast to be routinely obtained. With this stable system, we were able to characterize many polymer solar cell specimens, and consequently identified and verified the existence of an unexpected nanoparticle-phase. Furthermore, we were also able to observe the fine structures of an E. coli specimen, without staining, using this on-chip thin film phase plate. Our system, which can be installed on a commercial TEM, opens up exciting possibilities for TEM to characterize soft materials.