Reversible Laser-Induced Amplified Spontaneous Emission from Coexisting Tetragonal and Orthorhombic Phases in Hybrid Lead Halide Perovskites
Reversible Laser-Induced Amplified Spontaneous Emission from Coexisting Tetragonal and Orthorhombic Phases in Hybrid Lead Halide Perovskites
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DOI：
10.1002/adom.201500765
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发表时间：
2016-06-01
影响因子：
9
通讯作者：
Koehler, Anna
中科院分区：
文献类型：
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作者：
Panzer, Fabian;Baderschneider, Sebastian;Koehler, Anna
在不同的温度（5-300 K）和激发能量密度（21-1615 μ J cm（-2））下测量了卤化铅钙钛矿的光致发光。发现在163 K以上的四方晶相和163 K以下的正交晶相，当激发密度大于1 × 10 ~（18）cm ~（-3）时，都能观察到放大自发辐射（ASE）。获得这种激发密度所需的注量取决于温度和相位，因为激发的非辐射衰减是温度激活的，对于四方晶和正交晶相，分别具有85 +/- 20和24 +/- 5 meV的不同激活能。当样品在3.68 eV光子能量下预先暴露于超过630 μ J cm（-2）的能量密度时，除了正交相的ASE外，还可以在5 K下观察到通常在163 K以上的温度下普遍存在的来自四方相的ASE。这种额外的ASE可以通过温和加热到35 K或光学方式去除，通常通过暴露样品几秒钟，通量约为630 μ J cm（-2）。讨论了这种光致相变过程的物理机制。它表明，这种相变可以，在原则上，用于全光“写-读-擦”存储器设备。
The photoluminescence in a lead halide perovskite is measured for different temperatures (5-300 K) and excitation fluences (21-1615 mu J cm(-2)). It is found that amplified spontaneous emission (ASE) is observed for an excitation density larger than about 1 x 10(18) cm(-3) for both the tetragonal phase above 163 K and the orthorhombic phase below about 163 K. The fluence that is required to obtain this excitation density depends on temperature and phase since the nonradiative decay of excitations is temperature activated with different activation energies of 85 +/- 20 and 24 +/- 5 meV for the tetragonal and orthorhombic phase, respectively. The ASE from the tetragonal phase-usually prevailing at temperatures above about 163 K-can also be observed at 5 K, in addition to the ASE from the orthorhombic phase, when the sample is previously exposed to a fluence exceeding 630 mu J cm(-2) at a photon energy of 3.68 eV. This additional ASE can be removed by mild heating to 35 K or optically, by exposing the sample by typically a few seconds with a fluence around 630 mu J cm(-2). The physical mechanism underlying this optically induced phase transition process is discussed. It is demonstrated that this phase change can, in principle, be used for an all-optical "write-read-erase" memory device.