Ce3+-Doping to Modulate Photoluminescence Kinetics for Efficient CsPbBr3 Nanocrystals Based Light-Emitting Diodes
Ce3+-Doping to Modulate Photoluminescence Kinetics for Efficient CsPbBr3 Nanocrystals Based Light-Emitting Diodes
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Ce3 掺杂可调节基于 CsPbBr3 纳米晶体的高效发光二极管的光致发光动力学
DOI：
10.1021/jacs.7b11955
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发表时间：
2018
影响因子：
15
通讯作者：
Yu Shu-Hong
中科院分区：
文献类型：
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作者：
Yao Ji-Song;Ge Jing;Han Bo-Ning;Wang Kun-Hua;Yao Hong-Bin;Yu Hao-Lei;Li Jian-Hai;Zhu Bai-Sheng;Song Ji-Zhong;Chen Chen;Zhang Qun 张群;Zeng Hai-Bo;Luo Yi;Yu Shu-Hong
无机钙钛矿cspbbr3纳米晶体（NCs）是新兴的具有高色纯度和良好热稳定性的发光二极管（led）发光材料。它们的高光/电致发光效率对于制造高效led非常重要。在这里，我们提出了一种新的策略，通过一种简单的热注入方法，通过掺杂异价Ce3+离子来提高CsPbBr3NCs的光/电致发光效率。选择Ce3+离子作为CsPbBr3NCs的掺杂剂，是因为Ce3+离子具有相似的离子半径，且与溴形成的导带能级比Pb2+离子高，可以在不引入额外阱态的情况下保持钙钛矿结构的完整性。研究发现，将CsPbBr3NCs中Ce3+的掺杂量增加到2.88% （Ce相对于Pb的原子百分数），CsPbBr3NCs的光致发光量子产率（PLQY）达到89%，比未掺杂的CsPbBr3NCs提高了2倍。超快瞬态吸收和时间分辨光致发光（PL）光谱结果表明，Ce3+掺杂可以显著调节发光动力学，提高掺杂cspbbr3nc的发光效率。结果表明，采用Ce3+掺杂CsPbBr3NCs作为发光层制备的LED器件电致发光性能显著提高，外量子效率（EQE）由1.6提高到4.4%。
Inorganic perovskite CsPbBr3nanocrystals (NCs) are emerging, highly attractive light emitters with high color purity and good thermal stability for light-emitting diodes (LEDs). Their high photo/electroluminescence efficiencies are very important for fabricating efficient LEDs. Here, we propose a novel strategy to enhance the photo/electroluminescence efficiency of CsPbBr3NCs through doping of heterovalent Ce3+ions via a facile hot-injection method. The Ce3+cation was chosen as the dopant for CsPbBr3NCs by virtue of its similar ion radius and formation of higher energy level of conduction band with bromine in comparison with the Pb2+cation to maintain the integrity of perovskite structure without introducing additional trap states. It was found that by increasing the doping amount of Ce3+in CsPbBr3NCs to 2.88% (atomic percentage of Ce compared to Pb) the photoluminescence quantum yield (PLQY) of CsPbBr3NCs reached up to 89%, a factor of 2 increase in comparison with the native, undoped ones. The ultrafast transient absorption and time-resolved photoluminescence (PL) spectroscopy revealed that Ce3+-doping can significantly modulate the PL kinetics to enhance the PL efficiency of doped CsPbBr3NCs. As a result, the LED device fabricated by adopting Ce3+-doped CsPbBr3NCs as the emitting layers exhibited a pronounced improvement of electroluminescence with external quantum efficiency (EQE) from 1.6 to 4.4% via Ce3+-doping.