Enhancement of pH Tolerance in Conductive Al-Doped ZnO Nanofilms via Sequential Annealing
Enhancement of pH Tolerance in Conductive Al-Doped ZnO Nanofilms via Sequential Annealing
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DOI：
10.1021/acsaelm.0c01052
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发表时间：
2021-02-03
影响因子：
4.7
通讯作者：
Yanagida, Takeshi
中科院分区：
文献类型：
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作者：
Yan, Ruolin;Takahashi, Tsunaki;Yanagida, Takeshi
化学稳定和导电的金属氧化物纳米膜有望成为化学/生物传感器和光电化学应用的坚固的电极，这些应用要求苛刻的条件(例如，酸性或碱性环境)。在各种导电金属氧化物中，由于不可避免的刻蚀作用，沉积在衬底上的杂质掺杂的氧化锌纳米薄膜在化学上不耐酸性和碱性环境。在这里，我们展示了一种策略，以提高铝掺杂的氧化锌(AZO)纳米薄膜的pH耐受性，使用顺序退火法制备薄膜。该工艺首先在空气中进行退火，然后在锌蒸气气氛中进行退火热处理。尽管生长的AZO纳米膜在酸性和碱性溶液中迅速溶解，但在pH为3~11的缓冲溶液中，顺序退火的AZO纳米膜对化学腐蚀速率和电阻表现出良好的pH耐受性。当顺序退火(锌蒸气/空气)时，这种耐pH能力的提高作用明显减弱。从阴阳离子空位的补偿和氧化锌(0001)表面的表面极性的角度，讨论了连续退火的AZO纳米膜pH耐性提高的原因。
Chemically stable and electrically conductive metal oxide nanofilms are promising as robust electrodes for chemical/ biosensors and for photoelectrochemical applications, which require harsh conditions (e.g., acidic or basic environments). Among the various conductive metal oxides, impurity-doped ZnO nanofilms deposited on substrates are chemically nonresistive to acidic and basic environments because of the inevitable etching effects. Herein, we demonstrate a strategy to enhance the pH tolerance of Al-doped ZnO (AZO) nanofilms using a sequential annealing technique for film preparation. This technique involves first annealing in air followed by annealing in Zn vapor atmosphere. Although the as-grown AZO nanofilms rapidly dissolved in acidic and basic solutions, the sequentially annealed AZO nanofilms exhibited excellent pH tolerance toward the chemical etching rate and electrical resistance in buffer solutions, with pH ranging from 3 to 11. This enhancement effect of pH tolerance was considerably weakened when sequential annealing was performed in reverse (Zn vapor/air). The origin of the enhanced pH tolerance of the sequentially annealed AZO nanofilms is discussed in terms of the compensation of the anion/cation vacancies and the surface polarity of the ZnO(0001) surface.