Optical Investigation of Broadband White-Light Emission in Self-Assembled Organic-Inorganic Perovskite (C6H11NH3)2PbBr4
Optical Investigation of Broadband White-Light Emission in Self-Assembled Organic-Inorganic Perovskite (C6H11NH3)2PbBr4
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DOI：
10.1021/acs.jpcc.5b06211
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发表时间：
2015-10-15
影响因子：
3.7
通讯作者：
Boukheddaden, K.
中科院分区：
文献类型：
--
作者：
Yangui, A.;Garrot, D.;Boukheddaden, K.
用于太阳能转换的杂化有机钙钛矿（HOP）的性能正在推动对其发光特性的新兴趣。最近在层状HOP中观察到的宽可见光发射突出了它们作为白光发射体的潜力。提高材料的效率需要更好地了解其物理特性。我们提出了深入的实验研究的白光（WL）发射薄膜的（C6H11NH3）（2）PbBr4。宽带，强斯托克斯位移发射呈现出最大值在90 K时，激发在3.815 eV，低于这个温度共存的激子边缘发射。X射线和量热测量排除了作为WL发光的热行为的起源的相变的存在。自由激子发射淬灭在低温下，尽管结合能估计为280毫电子伏。时间分辨光致发光光谱揭示了宽发射的多组分性质。我们分析了这些组件作为温度和激发能的函数的依赖性。结果与自陷态的存在是一致的。自由激子的淬灭和WL发光衰减时间的热演化被解释为由对自陷的能量势垒的存在，估计类似于10毫电子伏。
The performance of hybrid organic perovskite (HOP) for solar energy conversion is driving a renewed interest in their light emitting properties. The recent observation of broad visible emission in layered HOP highlights their potential as white-light emitters. Improvement of the efficiency of the material requires a better understanding of its photophysical properties. We present in-depth experimental investigations of white-light (WL) emission in thin films of the (C6H11NH3)(2)PbBr4. The broadband, strongly Stokes shifted emission presents a maximum at 90 K when excited at 3.815 eV, and below this temperature coexists with an excitonic edge emission. X-rays and calorimetry measurements exclude the existence of a phase transition as an origin of the thermal behavior of the WL luminescence. The free excitonic emission quenches at low temperature, despite a binding energy estimated to 280 meV. Time-resolved photoluminescence spectroscopy reveals the multicomponent nature of the broad emission. We analyzed the dependence of these components as a function of temperature and excitation energy. The results are consistent with the existence of self-trapped states. The quenching of the free exciton and the thermal evolution of the WL luminescence decay time are explained by the existence of an energy barrier against self-trapping, estimated to similar to 10 meV.