Recent advances in preservation of the morphology of ZnO nanostructures during dye sensitization required the use of a two-step preparation procedure. The first step was the key for preserving ZnO materials morphology. It required exposing clean ZnO nanostructures to a gas-phase prop-2-ynoic acid (propiolic acid) in vacuum. This step resulted in the formation of a robust and stable surface-bound carboxylate with ethynyl groups available for further modification, for example, with click chemistry. This paper utilizes spectroscopic and microscopic investigations to answer several questions about this modification and to determine if the process can be performed under medium vacuum conditions instead of high vacuum procedures reported earlier. Comparing the results of the preparation process at medium vacuum of 0.5 Torr base pressure with the previously reported investigations of the same process in high vacuum of 10−5 Torr suggests that both processes lead to the formation of the same surface species, confirming that the proposed modification scheme can be widely applicable for ZnO sensitization procedures and does not require the use of high vacuum. Additional analysis comparing the computationally predicted surface structures with the results of spectroscopic investigations yields the more complete description of the surface species resulting from this approach.

中文翻译：

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高、中真空条件下ZnO与气相丙炔酸表面改性的比较

在染料敏化过程中保持 ZnO 纳米结构形态的最新进展需要使用两步制备程序。第一步是保持 ZnO 材料形貌的关键。它需要在真空中将干净的 ZnO 纳米结构暴露于气相丙-2-炔酸（丙炔酸）。此步骤导致形成坚固且稳定的表面结合的带有乙炔基的羧酸盐，可用于进一步修饰，例如通过点击化学。本文利用光谱和显微研究来回答有关这种修改的几个问题，并确定该过程是否可以在中真空条件下进行，而不是之前报道的高真空程序。将 0.5 Torr 基础压力的中真空下的制备过程的结果与之前报道的 10−5 Torr 高真空下的相同过程的研究结果进行比较表明，这两种过程都会导致相同表面物质的形成，从而证实了所提出的方法该改性方案可广泛适用于ZnO敏化过程，并且不需要使用高真空。将计算预测的表面结构与光谱研究结果进行比较的附加分析可以更完整地描述由这种方法产生的表面物种。