发表机构
McGill University; Istituto Nanoscienze – CNR; University College London（麦吉尔大学; 意大利国家研究委员会纳米科学研究所; 伦敦大学学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究利用时间分辨太赫兹光谱，揭示光激发CeO₂中同时存在Fröhlich型大空穴极化子与小电子极化子，明确其形成时间、特性及机制，为金属氧化物光催化剂的电荷转移动力学研究提供了基础。
AI 中文摘要
采用时间分辨太赫兹（THz）光谱探测CeO₂中的极化子形成过程。超快THz光导率主要由大空穴极化子和小电子极化子的贡献主导：离域的大空穴极化子以820±50 fs的时间尺度形成，属于Fröhlich型，其光导率可通过简单Drude模型很好地描述，瞬态空穴迁移率为100 cm²/Vs；小电子极化子通过与Ce晶格位点的局域耦合形成，该过程由晶格Born有效电荷的降低所揭示，伴随瞬态声子软化。这些结果确立了CeO₂的双极化子性质，为理解金属氧化物光催化剂中的电荷转移动力学提供了基础。
英文摘要
Time-resolved terahertz (THz) spectroscopy is used to probe polaron formation in CeO$_2$. The ultrafast THz photoconductivity is dominated by contributions from large hole and small electron polarons. Delocalized large hole polarons are formed on a $820 \pm 50$ fs time scale and are of Fröhlich type, with optical conductivity well described by a simple Drude model and a transient hole mobility of $100$ cm$^2$/Vs. Small electron polarons form via localized coupling to Ce lattice sites, revealed by reduction in the lattice Born effective charge causing a transient phonon softening. These results establish the dual polaron nature of CeO$_2$ and provide a basis for understanding charge transfer dynamics in metal oxide photocatalysts.
Comments11 pages, 6 figures (including Supplementary Information)
