Dayong Zhang

Kagome magnet RMn6Sn6 (R = Gd-Tm, Lu) with unusual lattice geometry and breaking of time-reversal symmetry is a promising platform to investigate the interaction of topology and magnetism. Since phonons play a vital role in the coupling between magnetism and topological fermions, a fundamental understanding of phonon dynamics is of great significance in this emerging research field. Here, we report a systematic investigation of ultrafast coherent phonon dynamics in GdMn6Sn6 crystals as a function of temperature and excitation fluence using time-resolved pump-probe spectroscopy. When the temperature decreases, the coherent phonon exhibits a hardening trend in frequency with a suppressed decay rate, which can be well-explained by the anharmonic scattering model. Unexpectedly, both the frequency and decay rate of coherent phonons are almost independent of excitation fluence, suggesting a weak electron–phonon scattering process in GdMn6Sn6.

In order to achieve a wider organic light-emitting diode (OLED) commercial popularity, solution processing inverted polymer light-emitting diode (iPLED) is a trend for further development, but there is still a gap for solution processing devices to achieve commercialization. The improvement of the performance iPLEDs is a research topic of intense current interest. The modification of the cathode interface layer of poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PF-NR2) can greatly improve the performance of the devices. However, the electron transportation of the cathode interface layer of PF-NR2 films is currently poor, and there is substantial interest in improving its electron transportation to further enhance the performance of organic optoelectronic devices. In this paper, gold nanoparticles (Au NPs) with a particle size of 20 nm were prepared and doped into the interface layer PF-NR2 at a specified ratio. The electron transportation of the interface layer of PF-NR2 was greatly improved, as judged by conductive atomic force microscopy measurements, which is due to the excellent conductivity of Au NPs. Herein, we demonstrate improved electron transportation of the interface layer by doping Au NPs in PF-NR2 film, which provides important and practical theoretical guidance and technical support for the preparation of high performance organic optoelectronic devices.