Conjugated Polyelectrolytes as Multifunctional Passivating and Hole‐Transporting Layers for Efficient Perovskite Light‐Emitting Diodes
Conjugated Polyelectrolytes as Multifunctional Passivating and Hole‐Transporting Layers for Efficient Perovskite Light‐Emitting Diodes
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共轭聚电解质作为多功能钝化层和空穴传输层用于高效Percent发光二极管
DOI：
10.1002/adma.201900067
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发表时间：
2019-04
影响因子：
29.4
通讯作者：
Seungjin Lee;Chung Hyeon Jang;Thanh Luan Nguyen;S. H. Kim;Kyung Min Lee;Kiseok Chang;S. Choi;S. Kwak;H. Woo;M. Song
中科院分区：
文献类型：
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作者：
Seungjin Lee;Chung Hyeon Jang;Thanh Luan Nguyen;S. H. Kim;Kyung Min Lee;Kiseok Chang;S. Choi;S. Kwak;H. Woo;M. Song
金属卤化物钙钛矿(MHPS)由于具有较高的颜色纯度和可调性，作为发光材料引起了人们的广泛关注。钙钛矿型发光二极管(PeLED)的一个关键问题是制备最佳的电荷传输层(CTL)，它具有理想的能级，可以有效地注入电荷，同时阻止相反的电荷，并能够在减少界面缺陷的情况下生长钙钛矿层。本文提出了两种不同反离子(K+和四甲基铵(TMA+))的聚荧苯基阴离子共轭聚电解质(CPE)作为多功能钝化和空穴传输层(HTL)。通过X射线光电子能谱、X射线衍射和密度泛函理论计算，研究了不同HTL衬底上生长的MHPS晶体的生长情况。含有TMA+反离子的CPE显著促进了钙钛矿的生长，抑制了界面缺陷，从而显著提高了发射性能和器件性能。通过老化和施加电应力，通过有效地重排钙钛矿中界面缺陷上的反离子，进一步提高了发光性能。最后，制备出了外量子效率为10.2%的高效甲酰胺三溴化铅准二维PELED。利用具有不同反离子的CPE作为CTL，可以作为控制界面缺陷和改善钙钛矿型光电器件性能的有效方法。
Metal halide perovskites (MHPs) have attracted significant attention as light‐emitting materials owing to their high color purities and tunabilities. A key issue in perovskite light‐emitting diodes (PeLEDs) is the fabrication of an optimal charge transport layer (CTL), which has desirable energy levels for efficient charge injection while blocking opposite charges and enabling perovskite layer growth with reduced interfacial defects. Herein, two poly(fluorene‐phenylene)‐based anionic conjugated polyelectrolytes (CPEs) with different counterions (K+ and tetramethylammonium (TMA+)) are presented as multifunctional passivating and hole‐transporting layers (HTLs). The crystal growth of MHPs grown on different HTLs is investigated through X‐ray photoelectron spectroscopy, X‐ray diffraction, and density functional theory calculation. The CPE bearing the TMA+ counterions remarkably improves the growth of perovskites with suppressed interfacial defects, leading to significantly enhanced emission properties and device performance. The luminescent properties are further enhanced via aging and electrical stress application with effective rearrangement of the counterions on the interfacial defects in the perovskites. Finally, efficient formamidinium lead tribromide‐based quasi‐2D PeLEDs with an external quantum efficiency of 10.2% are fabricated. Using CPEs with varying counterions as a CTL can serve as an effective method for controlling the interfacial defects and improving perovskite‐based optoelectronic device properties.