Zhang Zhen-Yu, Wang Hai-Yu, Zhang Yan-Xia, Li Kai-Jiao, Zhan Xue-Peng, Gao Bing-Rong, Chen Qi-Dai, Sun Hong-Bo
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
College of Physics, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
Phys Chem Chem Phys. 2017 Jan 18;19(3):2217-2224. doi: 10.1039/c6cp07522c.
In the past few years, organometal halide light-emitting perovskite thin films and colloidal nanocrystals (NCs) have attracted significant research interest in the field of highly purified illuminating applications. However, knowledge of photoluminescence (PL) characteristics, such as amplified spontaneous emission (ASE) of larger-sized perovskite crystals, is still relatively scarce. Here, we presented room-temperature size-dependent spontaneous emission (SE) and ASE of the organometal halide CHNHPbBr perovskite cubic microcrystals pumped through one-photon-(1P) and two-photon-(2P) excitation paradigms. The results showed that the optical properties of SE and ASE were sensitively dependent on the sizes of perovskite microcrystals irrespective of whether 1P or 2P excitation was used. Moreover, by comparing the spectral results of 1P- and 2P-pumped experiments, 2P pumping was found to be an effective paradigm to reduce thresholds by one order of magnitude. Finally, we carried out fluences-dependent time-resolved fluorescence dynamics experiments to study the underlying effects of these scale-dependent SE and ASE. We found that the photoluminescence (PL) recombination rates sensitively became faster with increasing carriers' densities, and that the ASE pumped from larger-sized CHNHPbBr perovskite cubic microcrystals showed faster lifetimes. This work shows that micro-sized perovskite cubic crystals could be the ideal patterns of perovskite materials for realizing ASE applications in the future.
在过去几年中，有机金属卤化物发光钙钛矿薄膜和胶体纳米晶体（NCs）在高纯度照明应用领域引起了重大研究兴趣。然而，对于光致发光（PL）特性的了解，例如较大尺寸钙钛矿晶体的放大自发辐射（ASE），仍然相对较少。在此，我们展示了通过单光子（1P）和双光子（2P）激发模式泵浦的有机金属卤化物CHNHPbBr钙钛矿立方微晶在室温下尺寸依赖的自发辐射（SE）和ASE。结果表明，无论使用1P还是2P激发，SE和ASE的光学性质都敏感地依赖于钙钛矿微晶的尺寸。此外，通过比较1P和2P泵浦实验的光谱结果，发现2P泵浦是将阈值降低一个数量级的有效模式。最后，我们进行了依赖于fluence的时间分辨荧光动力学实验，以研究这些尺寸依赖的SE和ASE的潜在影响。我们发现，随着载流子密度的增加，光致发光（PL）复合速率敏感地加快，并且从较大尺寸的CHNHPbBr钙钛矿立方微晶泵浦的ASE显示出更快的寿命。这项工作表明，微米尺寸的钙钛矿立方晶体可能是未来实现ASE应用的理想钙钛矿材料模式。
