Ultrafast Interfacial Electron and Hole Transfer from CsPbBr3 Perovskite Quantum Dots

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• 作者：Kaifeng Wu ; Guijie Liang ; Qiongyi Shang ; Yueping Ren ; Degui Kong ; Tianquan Lian
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：137
• 期：40
• 页码：12792-12795
• 全文大小：327K
• ISSN：1520-5126

文摘

Recently reported colloidal lead halide perovskite quantum dots (QDs) with tunable photoluminescence (PL) wavelengths covering the whole visible spectrum and exceptionally high PL quantum yields (QYs, 50鈥?0%) constitute a new family of functional materials with potential applications in light-harvesting and -emitting devices. By transient absorption spectroscopy, we show that the high PL QYs (鈭?9%) can be attributed to negligible electron or hole trapping pathways in CsPbBr₃ QDs: 鈭?4% of lowest excitonic states decayed with a single-exponential time constant of 4.5 卤 0.2 ns. Furthermore, excitons in CsPbBr₃ QDs can be efficiently dissociated in the presence of electron or hole acceptors. The half-lives of electron transfer (ET) to benzoquinone and subsequent charge recombination are 65 卤 5 ps and 2.6 卤 0.4 ns, respectively. The half-lives for hole transfer (HT) to phenothiazine and the subsequent charge recombination are 49 卤 6 ps and 1.0 卤 0.2 ns, respectively. The lack of electron and hole traps and fast interfacial ET and HT rates are key properties that may enable the development of efficient lead halide perovskite QDs-based light-harvesting and -emitting devices.