Intrinsic Lead Ion Emissions in Zero-Dimensional Cs4PbBr6 Nanocrystals
Intrinsic Lead Ion Emissions in Zero-Dimensional Cs4PbBr6 Nanocrystals
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DOI：
10.1021/acsenergylett.7b01026
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发表时间：
2017-11
影响因子：
22
通讯作者：
Jun Yin;Yuhai Zhang;A. Bruno;C. Soci;O. Bakr;J. Brédas;O. Mohammed
中科院分区：
文献类型：
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作者：
Jun Yin;Yuhai Zhang;A. Bruno;C. Soci;O. Bakr;J. Brédas;O. Mohammed
我们结合实验和理论方法研究了零维 (0D) 钙钛矿纳米晶体 (NC) 中的本征铅离子 (Pb2+) 发射。 “非发射”（高度抑制绿光发射）和发射（亮绿色发射）Cs4PbBr6 NC 的温度依赖性光致发光实验表明，发射光谱在紫外 (UV) 光谱范围内分裂为高能和低能跃迁。在非发射情况下，我们将大约 350 nm 处的高能 UV 发射归因于 Pb2+ 离子中允许的 3P1 到 1S0 的光学跃迁，并将大约 400 nm 处的低能 UV 发射归因于 0D NC 主晶格（D 态）中涉及的电荷转移态。在发射性 Cs4PbBr6 NC 中，除了广泛的紫外线发射之外，我们还证明了能量从 Pb2+ 离子到绿色发光中心的转移。根据密度泛函理论，Cs4PbBr6 NC 中的光学声子模式可以分配给 Pb-Br 拉伸和摇摆运动。
We investigate the intrinsic lead ion (Pb2+) emissions in zero-dimensional (0D) perovskite nanocrystals (NCs) using a combination of experimental and theoretical approaches. The temperature-dependent photoluminescence experiments for both “nonemissive” (highly suppressed green emission) and emissive (bright green emission) Cs4PbBr6 NCs show a splitting of emission spectra into high- and low-energy transitions in the ultraviolet (UV) spectral range. In the nonemissive case, we attribute the high-energy UV emission at approximately 350 nm to the allowed optical transition of 3P1 to 1S0 in Pb2+ ions and the low-energy UV emission at approximately 400 nm to the charge-transfer state involved in the 0D NC host lattice (D-state). In the emissive Cs4PbBr6 NCs, in addition to the broad UV emission, we demonstrate that energy transfer occurs from Pb2+ ions to green luminescent centers. The optical phonon modes in Cs4PbBr6 NCs can be assigned to both Pb–Br stretching and rocking motions from density functional theo...