Zhu Xixiang, Dai Shu-Wen, Lai Ying-Lin, Dou Yixuan, Wang Miaosheng, Ho Jian-Syun, Chang Yi-An, Chuang Yung-Tang, Lin Hao-Wu, Hu Bin
Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States.
Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Sec. 2, Kuang-Fu Road, Hsinchu 30013, Taiwan.
J Phys Chem Lett. 2021 Dec 16;12(49):11894-11901. doi: 10.1021/acs.jpclett.1c02978. Epub 2021 Dec 8.
This paper reports packing-shape effects of amplified spontaneous emission (ASE) through orbital polarization dynamics between light-emitting excitons by stacking perovskite (MAPbBr) quantum dots (QDs sized between 10 nm and 14 nm) into rod-like and diamond-like aggregates. The rod-like packing shows a prolonged photoluminescence (PL) lifetime (184 ns) with 3 nm red-shifted peak (525 nm) as compared to the diamond-like packing (PL peak, 522 nm; lifetime, 19 ns). This indicates that the rod-like packing forms a stronger interaction between QDs with reduced surface-charged defects, leading to surface-to-inside property-tuning capability with an ASE. Interestingly, the ASE enabled by rod-like packing shows an orbit-orbit polarization interaction between light-emitting excitons, identified by linearly/circularly polarized pumping conditions. More importantly, the polarization dynamics is extended to the order of nanoseconds in the rod-like assembly, determined by the observation that within the ASE lifetime (2.54 ns) the rotating pumping beam polarization direction largely affects the coherent interaction between light-emitting excitons.
本文报道了通过将钙钛矿（MAPbBr）量子点（尺寸在10纳米至14纳米之间）堆叠成棒状和类金刚石状聚集体，利用发光激子之间的轨道极化动力学实现放大自发辐射（ASE）的堆积形状效应。与类金刚石状堆积（PL峰，522纳米；寿命，19纳秒）相比，棒状堆积显示出延长的光致发光（PL）寿命（184纳秒），峰值红移3纳米（525纳米）。这表明棒状堆积在量子点之间形成了更强的相互作用，表面带电缺陷减少，从而具有通过ASE进行表面到内部性质调节的能力。有趣的是，棒状堆积实现的ASE在发光激子之间显示出轨道 - 轨道极化相互作用，这通过线性/圆偏振泵浦条件得以确定。更重要的是，在棒状组装中，极化动力学扩展到了纳秒级，这是由以下观察结果确定的：在ASE寿命（2.54纳秒）内，旋转泵浦光束的极化方向在很大程度上影响发光激子之间的相干相互作用。
