中国物理B ›› 2021, Vol. 30 ›› Issue (11): 114214-114214.doi: 10.1088/1674-1056/ac1b8d

所属专题: SPECIAL TOPIC — Optical field manipulation

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Theory of multiphoton photoemission disclosing excited states in conduction band of individual TiO2 nanoparticles

Bochao Li(李博超), Hao Li(李浩), Chang Yang(杨畅), Boyu Ji(季博宇), Jingquan Lin(林景全), and Toshihisa Tomie(富江敏尚)   

  1. School of Science, Changchun University of Science and Technology, Changchun 130022, China
  • 收稿日期:2021-06-20 修回日期:2021-07-25 接受日期:2021-08-07 出版日期:2021-10-13 发布日期:2021-10-22
  • 通讯作者: Jingquan Lin, Toshihisa Tomie E-mail:linjinquan@cust.edu.cn;tomie@cust.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 91850109, 11474040, 61605017, and 61775021) and the “111” Project of China (Grant No. D17017).

Theory of multiphoton photoemission disclosing excited states in conduction band of individual TiO2 nanoparticles

Bochao Li(李博超), Hao Li(李浩), Chang Yang(杨畅), Boyu Ji(季博宇), Jingquan Lin(林景全), and Toshihisa Tomie(富江敏尚)   

  1. School of Science, Changchun University of Science and Technology, Changchun 130022, China
  • Received:2021-06-20 Revised:2021-07-25 Accepted:2021-08-07 Online:2021-10-13 Published:2021-10-22
  • Contact: Jingquan Lin, Toshihisa Tomie E-mail:linjinquan@cust.edu.cn;tomie@cust.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 91850109, 11474040, 61605017, and 61775021) and the “111” Project of China (Grant No. D17017).

摘要: A theory of multiphoton photoemission is derived to explain the experimentally observed monotonic decrease with the wavelength in the electron yield of TiO2 nanoparticles (NPs) by as large as four orders of magnitude. It is found that the fitting parameter corresponds to the energy position of Ti3d eg and t2g states, and the derived theory is a novel diagnostic of excited states in the conduction band, very importantly, applicable to individual NPs. The difference between four-photon slope NPs and three-photon slope NPs is attributed to the difference in defect density. The success of the theory in solving the puzzling result shows that thermal emission from high-lying levels may dominate over direct multiphoton ionization in solids when the photon number larger than four is required.

关键词: multiphoton photoemission, nanoparticles, thermal emission, TiO2

Abstract: A theory of multiphoton photoemission is derived to explain the experimentally observed monotonic decrease with the wavelength in the electron yield of TiO2 nanoparticles (NPs) by as large as four orders of magnitude. It is found that the fitting parameter corresponds to the energy position of Ti3d eg and t2g states, and the derived theory is a novel diagnostic of excited states in the conduction band, very importantly, applicable to individual NPs. The difference between four-photon slope NPs and three-photon slope NPs is attributed to the difference in defect density. The success of the theory in solving the puzzling result shows that thermal emission from high-lying levels may dominate over direct multiphoton ionization in solids when the photon number larger than four is required.

Key words: multiphoton photoemission, nanoparticles, thermal emission, TiO2

中图分类号:  (Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift)

  • 42.50.Hz
42.65.Sf (Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamics) 42.79.Ek (Solar collectors and concentrators)