Highly Luminescent Phase-Stable CsPbl3 Perovskite Quantum Dots Achieving Near 100% Absolute Photoluminescence Quantum Yield
Highly Luminescent Phase-Stable CsPbl3 Perovskite Quantum Dots Achieving Near 100% Absolute Photoluminescence Quantum Yield
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DOI：
10.1021/acsnano.7b05442
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发表时间：
2017-10-01
期刊：
影响因子：
17.1
通讯作者：
Shen, Qing
中科院分区：
文献类型：
--
作者：
Liu, Feng;Zhang, Yaohong;Shen, Qing
钙钛矿型量子点作为一种新型的胶体纳米晶，由于其良好的光电性能和良好的化学可加工性，在基础研究和商业应用方面都受到了极大的关注。由于胶体量子点具有广泛的潜在应用前景，因此合成高晶体质量的胶体量子点就显得尤为重要。然而，像大多数常见的量子点系统，如CdSe和PbS，那些已报道的钙钛矿型量子点仍然存在一定密度的陷阱缺陷，导致有害的非辐射复合中心，从而猝灭发光。在本文中，我们发现在CsPbI3钙钛矿型量子点中可以获得高达100%的室温光致发光量子产率，这标志着几乎完全消除了陷阱缺陷。这是通过我们改进的合成方案实现的，该方案包括引入有机油类化合物三辛基膦PbI(2)(TOP-PbI2)作为反应前体，这也导致得到的CsPbI3 QD溶液的稳定性显著提高。用时间分辨瞬变吸收光谱进行的超快动力学分析证明，我们的量子点中电子或空穴捕获路径可以忽略不计，这解释了如此高的量子效率。我们预计，理想的钙钛矿型量子点的成功合成将对其在基于量子点的光收集和发射器件中的应用产生深远的影响。
Perovskite quantum dots (QDs) as a new type of colloidal nanocrystals have gained significant attention for both fundamental research and commercial applications owing to their appealing optoelectronic properties and excellent chemical processability. For their wide range of potential applications, synthesizing colloidal QDs with high crystal quality is of crucial importance. However, like most common QD systems such as CdSe and PbS, those reported perovskite QDs still suffer from a certain density of trapping defects, giving rise to detrimental nonradiative recombination centers and thus quenching luminescence. In this paper, we show that a high room-temperature photoluminescence quantum yield of up to 100% can be obtained in CsPbI3 perovskite QDs, signifying the achievement of almost complete elimination of the trapping defects. This is realized with our improved synthetic protocol that involves introducing organolead compound trioctylphosphinePbI(2) (TOP-PbI2) as the reactive precursor, which also leads to a significantly improved stability for the resulting CsPbI3 QD solutions. Ultrafast kinetic analysis with time-resolved transient absorption spectroscopy evidence the negligible electron or hole-trapping pathways in our QDs, which explains such a high quantum efficiency. We expect the successful synthesis of the "ideal" perovskite QDs will exert profound influence on their applications to both QD-based light-harvesting and -emitting devices.