Unraveling Electron Transfer Dynamics between Carbon Quantum Dots and TiO2 With Spectroscopic Technique.
Y. F. Guo1*, C. T. Yuan*1, J. L. Shen*1, T. N. Lin1, S. R. Santiago1
1Department of Physics, Chung Yuan Christian University, Chung Li, Taiwan
* presenting author:Yu Fang Guo, email:r810199y@hotmail.com
Recently, colloidal Carbon quantum dots (CQDs) have attracted much attention due to some unique photo-physical properties, such as hot-electron injection and multiple-exciton generation [1,2], which are beneficial for promising applications in fabricating solution-processed photovoltaic devices [3]. In order to serve as photo-sensitizers, the photo-generated electrons/holes within the CQDs need to be extracted efficiently by electrodes or electron/hole transporting layer prior to radiative and non-radiative recombination pathways [4]. Here, CQDs with two different sizes can be fabricated using simple laser-ablation methods. To unravel electron-transfer dynamics from CQDs to TiO2, a spectroscopic technique is used for CQDs with carboxyl ligands anchored onto the TiO2 surface in the presence of hole scavenges. The electron-transfer dynamics can be further analyzed using Marcus theory and the related injection rates can be derived. Such an understanding is useful for further designing high-performance photovoltaic devices based on solution-processed, cost-effective CQDs.

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Keywords: Colloidal Carbon quantum dots, electron transfer dynamics, Marcus theory