Liu Sheng, Sun Shishuai, Gan Chee Kwan, Del Águila Andrés Granados, Fang Yanan, Xing Jun, Do T Thu Ha, White Timothy J, Li Hongguo, Huang Wei, Xiong Qihua
School of Science, Tianjin University of Technology, Tianjin 300384, China.
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
Sci Adv. 2019 Jul 26;5(7):eaav9445. doi: 10.1126/sciadv.aav9445. eCollection 2019 Jul.
The hybrid nature and soft lattice of organolead halide perovskites render their structural changes and optical properties susceptible to external driving forces such as temperature and pressure, remarkably different from conventional semiconductors. Here, we investigate the pressure-induced optical response of a typical two-dimensional perovskite crystal, phenylethylamine lead iodide. At a moderate pressure within 3.5 GPa, its photoluminescence red-shifts continuously, exhibiting an ultrabroad energy tunability range up to 320 meV in the visible spectrum, with quantum yield remaining nearly constant. First-principles calculations suggest that an out-of-plane quasi-uniaxial compression occurs under a hydrostatic pressure, while the energy is absorbed by the reversible and elastic tilting of the benzene rings within the long-chain ligands. This anisotropic structural deformation effectively modulates the quantum confinement effect by 250 meV via barrier height lowering. The broad tunability within a relatively low pressure range will expand optoelectronic applications to a new paradigm with pressure as a tuning knob.
有机铅卤化物钙钛矿的混合性质和软晶格使其结构变化和光学性质易受温度和压力等外部驱动力的影响，这与传统半导体有显著不同。在此，我们研究了典型二维钙钛矿晶体苯乙胺碘化铅的压力诱导光学响应。在3.5吉帕的中等压力下，其光致发光连续红移，在可见光谱中展现出高达320毫电子伏特的超宽能量可调范围，量子产率几乎保持不变。第一性原理计算表明，在静水压力下会发生面外准单轴压缩，而能量通过长链配体中苯环的可逆弹性倾斜被吸收。这种各向异性结构变形通过降低势垒高度有效地将量子限制效应调制了250毫电子伏特。在相对低的压力范围内的宽可调性将把光电子应用扩展到以压力作为调节旋钮的新范式。
