We report the grain growth from the nanoscale to microscale and a transformation sequence from Bi → β-Bi₂O₃ → γ-Bi₂O₃ → α-Bi₂O₃ with the increase of annealing temperature. The room temperature (RT) stabilization of β-Bi₂O₃ nanoparticles (NPs) was attributed to the effect of reduced surface energy due to adsorbed carbon species, and oxygen vacancy defects may have played a significant role in the RT stabilization of γ-Bi₂O₃ NPs. An enhanced red emission band was evident from all the samples attributed to oxygen-vacancy defects formed during the growth process in contrast with the observed white emission band from the air annealed Bi ingots. Based on our experimental findings, the air annealing induced oxidation of Bi NPs and transformation mechanism within various Bi₂O₃ nano-polymorphs are presented. The outcome of this study suggests that oxygen vacancy defects at the nanoscale play a significant role in both structural stabilization and phase transformation within various Bi₂O₃ nano-polymorphs, which is significant from theoretical consideration.

中文翻译：

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各种Bi2O3纳米多晶型物的相变和室温稳定性：氧空位缺陷的影响和由于吸附的碳物质而降低的表面能

我们选自Bi→β-BI报告从纳米级到微米级的晶粒生长和变换序列₂ ö ₃ →γ-Bi系₂ ö ₃ →α-Bi系₂ ö ₃与退火温度的升高。室温（RT）的稳定化β-Bi系₂ ö ₃纳米颗粒（NP）是由于降低的表面能的效果，由于吸附的碳物质和氧空位缺陷可以都起到的RT稳定化作用显著γ- Bi ₂ O ₃NP。与从空气退火的Bi锭观察到的白色发射带相反，在所有样品中明显的红色发射带增强是由于生长过程中形成的氧空位缺陷引起的。根据我们的实验结果，提出了空气退火诱导的Bi NPs的氧化和各种Bi ₂ O ₃纳米多晶型物内的转化机理。这项研究的结果表明，纳米级的氧空位缺陷在各种Bi ₂ O ₃纳米多晶型物的结构稳定和相变中都起着重要作用，这从理论上来说是重要的。