太赫兹时间分辨系统研究有机卤化物钙钛矿薄膜的超快太赫兹调制

摘要

研究了利用太赫兹时间分辨系统研究有机卤化物钙钛矿薄膜(CH3NH3PbI3 and CH3NH3PbI3-xClx)的皮秒尺度的超快太赫兹调制特性.在光激发作用下出现了太赫兹透射波的瞬时下降.相比于CH3NH3PbI3薄膜,在光激发作用下CH3NH3PbI3-xClx薄膜展现了更高的调制深度(10％).通过测算材料的电导率及载流子浓度,其调制机理为瞬态光激发载流子浓度上升.实验结果表明,CH3NH3PbI3-xClx薄膜可作为一种高效超快太赫兹调制器件.%Ultrafast terahertz (THz) modulation characteristics of organolead halide perovskite films (CH3NH3PbI3 and CH3NH3PbI3-xClx) were investigated on picosecond time scales using time-resolved THz spectroscopy.Upon photo-excitation,a transient decrease in THz transmission was observed.Compared with CH3NH3PbI3,CH3NH3PbI3-xClx showed a better modulation depth (10％) within the range of the photo-excitation powers used.The mechanism underpinning this photoconductive ultrafast response was determined by measuring the transmission properties and calculating the carrier density.The larger crystalline bulk of the CH3NH3PbI3-xClx film produced higher carrier densities than the CH3NH3PbI3 film.These results demonstrate that CH3NH3PbI3-xClx films are promising materials for developing high-performance THz modulators and ultrafast switchable THz photoelectric devices.