Observation of electron–phonon coupling and linear dichroism in PL spectra of ultra-small CsPbBr3 nanoparticle solution
Chengqiang Wang,
Tao Song,
Pingyuan Yan,
Shu Hu,
Chenhong Xiang,
Zihan Wu,
Heng Li,
Haibin Zhao,
Lili Han,
Chuanxiang Sheng
Affiliations
Chengqiang Wang
State Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China; School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
Tao Song
College of Chemistry and Chemical Engineering, Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, Lanzhou 730000, China
Pingyuan Yan
State Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China; School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Shu Hu
School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Chenhong Xiang
School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Zihan Wu
School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Heng Li
School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Haibin Zhao
State Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China; Corresponding authors.
Lili Han
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; Corresponding authors.
Chuanxiang Sheng
State Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China; School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Corresponding authors.
Blue-emission (∼480 nm) CsPbBr3 nanoparticles with ultra-small size (∼2.1 nm) are synthesized using the liquid nitrogen freezing with the ligand of dodecylbenzene sulfonic acid (DBSA). Asymmetric narrow emissions at the low energy side, with the full width at half-maximum of ∼20 nm, are observed in solution and film at room temperature. The spectral asymmetry is mainly ascribed to phonon vibronic replica with averaged phonon energy of ∼40 meV. Moreover, exciting this CsPbBr3 nanoparticles solution using linearly polarized 6 ns pulsed laser at 355 nm, we observe polarized emission with polarization degree (PPL) of ∼7%, and PPL decreases more than 20% in the vibronic progression. However, the PPL goes to zero in frozen solutions as well as in films. Thus we speculate the polarized emission is due to the photoinduced re-alignment of nanoparticles, and the diminished PPL at the phonon side band may be due to the non-adiabatic electronic-to-vibronic transitions. The novel phenomena from the ultra-small CsPbBr3 nanoparticle demonstrated in this work may provide fundamental insights into its photophysics with direct implications for optoelectronics.
