Recently, faculty and students from Institute of Solid-State Laser and Ultrafast Photonics, Institute of Laser Engineering, School of Physics and Optoelectronic Engineering, have made important progress in the study of ultrafast carrier dynamics of optoelectronic functional crystals, and the related research results are summarized in the article "Anisotropic carrier dynamics and laser fabricated luminescent patterns on oriented single-crystal". The research results are published online in Nature Communications under the title of "Anisotropic carrier dynamics and laser fabricated luminescent patterns on oriented single-crystal perovskite wafers", which is of great significance in promoting the practical application of functional crystals in the field of photovoltaics.
The first author of the paper is Ge Chao, assistant researcher of School of Physics and Optoelectronic Engineering, and Li Yachao, doctoral student of the School of Physics and Optoelectronic Engineering, while Ge Chao, assistant researcher and Song Haiying, associate researcher of BUT, and Zhang Wenkai, professor of Beijing Normal University, and Liu Yang, professor of Shandong University, are the co-corresponding authors. This research was supported by the National Natural Science Foundation of China and the Scientific Research Program of Beijing Municipal Education Commission.
In recent years, chalcogenide materials and their applications in optoelectronics have attracted much attention. However, an in-depth understanding of their anisotropic behavior in ultrafast carrier dynamics is still lacking. To fill this gap, the research team has revealed, for the first time on a picosecond time scale, the evolution of the anisotropic dynamics of photo-excited carriers polarized within and between crystalline planes with different orientations, based on high-quality, differently oriented MAPbBr3 single-crystal wafers. This discovery provides an in-depth understanding of the relaxation pathways of ultrafast carriers from a crystallographic point of view, which is of great significance for exploring and expanding the applications of chalcogenide single crystals in the field of ultrafast optoelectronics, such as optical modulators, high-speed optical polarization sensors and ballistic transistors.
In addition, by employing femtosecond laser two-photon processing, the research team successfully prepared three orders of magnitude fluorescence-enhanced luminescence patterns. The fluorescence enhancement mechanism behind was deeply analyzed from a multidimensional spatial (bulk and micro/nano scales) and temporal (steady state and transient) perspective, which provides a convenient top-down strategy to enhance the photoluminescence intensity of bulk crystals. This study provides a profound understanding of the ultrafast carrier dynamics of MAPbBr3 by focusing on the crystallographic perspective, which is expected to provide more guidance for the orientation-selective utilization of chalcogenide hot carriers in optoelectronics in the future.
Progress in the study of ultrafast carrier dynamics in optoelectronic functional crystals at NIT Important for chalcogenide single-crystal applications
Kinetic evolution of photoexcited carriers in the (100), (110) and (111) crystal faces of MAPbBr3 crystals and the mechanism of femtosecond laser-induced fluorescence enhancement.
