Leveraging a Stable Perovskite Composite to Satisfy Blue Electroluminescence Standards
Leveraging a Stable Perovskite Composite to Satisfy Blue Electroluminescence Standards
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利用稳定的Percent复合材料满足蓝色电致发光标准
DOI：
10.1021/acsmaterialslett.1c00404
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发表时间：
2021
影响因子：
11.4
通讯作者：
Aditya Mishra;Masoud Alahbakhshi;Q. Gu;A. Zakhidov;J. Slinker
中科院分区：
文献类型：
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作者：
Aditya Mishra;Masoud Alahbakhshi;Q. Gu;A. Zakhidov;J. Slinker
蓝色电致发光是许多光电和照明应用的基础，混合卤化物钙钛矿发光器件正在开发中以满足技术需求。然而，蓝色钙钛矿器件缺乏稳定性，主要是因为在操作期间卤化物偏析，这会使底层钙钛矿结构退化。饱和和稳定的蓝色发射是用混合卤化物钙钛矿、聚合物电解质和锂盐的合理材料共混物实现的，所述锂盐选择性地抑制钙钛矿离子运动，同时促进盐添加剂的传输。这种方法产生的蓝色电致发光峰值为464 nm，超过了标准基准，亮度最大值为540 cd/m2，在恒流驱动下工作稳定。通过光致发光、电致发光、扫描电子显微镜和原子力显微镜研究探索了聚合物和盐添加剂的作用。关于该器件，盐离子改善了双电层的形成，并选择性地移动代替钙钛矿离子，而聚合物改善了膜的均匀性和光滑度。从根本上说，每个组件被证明有助于抑制卤化物偏析高度稳定的电致发光。蓝光发射是包括显示器、指示器、照明和激光器在内的新兴技术的高度期望的目标。特别地，真正的全色显示器需要蓝色发射，蓝色发射对于需要高显色指数的照明是必需的，并且可以通过磷光体下转换以产生其他颜色。此外，随着智能技术将更多功能带入主流，美观和无缝集成对于公众采用这些技术是必要的。因此，能够实现灵活性、一致性、色纯度和低成本加工的材料提供了竞争优势。金属卤化物钙钛矿通过溶液处理和多样化的组成离子表现出这些关键优势，产生不同的发射颜色以及高的电子和离子电导率。为了这些目的，现在已经出现了几种在钙钛矿发光二极管中产生蓝色电致发光（EL）的努力。这些器件通常需要多层，在接近技术色彩标准的同时，产生了中等至高的亮度和效率（表S1）。尽管取得了这些令人鼓舞的成果，但稳定性仍然是其在下一代电子产品中实施的一个重大障碍（表S1）。诸如滞后、颜色漂移、发光猝灭、电极腐蚀和电导率损失的不稳定性与钙钛矿的本征离子的运动相关。需要一种实用的材料方法和合理的器件设计来抑制钙钛矿离子运动，同时保持有效的操作。我们的策略包括在具有合理材料混合物的设备内产生差异化的离子运动。这些材料选择性地移动添加剂离子，同时限制钙钛矿离子的传输，正如我们通过光致发光和电致发光测量所证明的那样。这种材料的混合物也被用来生产光滑，无针孔的薄膜，具有最小的缺陷，我们证明了AFM和SEM。为了实现具有最佳薄膜形态的差异化离子传输，我们结合了混合卤化物钙钛矿，两种聚电解质和盐添加剂。特别是，我们共混CsPbBr1.43Cl1.57与聚（环氧乙烷）（PEO），聚（乙烯基吡咯烷酮）（PVP），和LiPF 6。我们从溶液中浇铸这些材料的薄膜以形成简单的发光接收时间：2021年7月12日接受时间：2021年7月27日Leter www.acsmaterialsletters.org ©美国化学学会1357 https://doi.org/10.1021/acsmaterialslett.1c00404 ACS Materials Lett. 2021，3，1357−1362 D ow nl oa de d vi a U N IV O F T E X A S A T D A L L A S on A ug us t 1 7，2 02 1 at 1 6：23：0 1（U T C）. See e e ht tp s：//p ub s. AC S。或g/ sh ar in gg ui de lines for or o pt io ns on how to le gi tim at el y sh ar e publ is he dartic le s.
Blue electroluminescence is fundamental for many optoelectronic and lighting applications, and mixed halide perovskite light-emitting devices are under development to meet the technological demands. However, the stability of blue perovskite devices is lacking, primarily because of the halide segregation during operation that degrades the underlying perovskite structure. Saturated and stable blue emission was accomplished with a rational materials blend of a mixed halide perovskite, polymer electrolytes, and a lithium salt that selectively suppressed perovskite ion motion while facilitating the transport of the salt additive. This approach produced blue electroluminescence peaked at 464 nm that surpassed standard benchmarks with a luminance maximum of 540 cd/m and stable operation under constant current driving. The role of the polymer and salt additives was explored by photoluminescence, electroluminescence, scanning electron microscopy, and atomic force microscopy studies. Concerning the device, the salt ions improve electrical double layer formation and selectively move in place of the perovskite ions, while the polymers improve the uniformity and smoothness of the films. Fundamentally, each component is shown to contribute to the suppression of halide segregation for highly stable electroluminescence. Blue light emission is a highly desired target for emerging technologies, including displays, indicators, lighting, and lasers. In particular, blue emission is needed for genuinely full-color displays, is requisite for lighting requiring high color rendering indices, and can be down-converted by phosphors to produce other colors. Furthermore, as smart technologies bring additional functionalities into the mainstream, aesthetically pleasing and seamless integration are necessary for public adoption of these technologies. Therefore, materials enabling flexibility, conformability, color purity, and low-cost processing offer a competitive advantage. Metal halide perovskites exhibit these critical advantages through solution processing and diversified constituent ions, yielding distinct emission colors as well as high electronic and ionic conductivities. To these ends, several efforts have now emerged to produce blue electroluminescence (EL) in perovskite light-emitting diodes. These devices, generally requiring multiple layers, have yielded moderate to high luminance and efficiency while approaching technological color standards (Table S1). Despite these encouraging results, stability remains a significant hurdle to their implementation in next-generation electronics (Table S1). Instabilities such as hysteresis, color drift, luminescence quenching, electrode corrosion, and loss of conductivity are associated with the motion of the intrinsic ions of the perovskite. A practical materials approach and rational device design are needed to suppress perovskite ion motion while maintaining efficient operation. Our strategy involves producing differentiated ion motion within a device with a rational materials blend. The materials selectively move additive ions while restricting the transport of perovskite ions, as we demonstrate through photoluminescence and electroluminescence measurements. This materials blend is also utilized to produce smooth, pinhole-free films with minimal defects, as we demonstrate by AFM and SEM. To accomplish differentiated ion transport with optimal thinfilm morphology, we combined a mixed-halide perovskite, two polyelectrolytes, and a salt additive. In particular, we blended CsPbBr1.43Cl1.57 with poly(ethylene oxide) (PEO), poly(vinylpyrrolidone) (PVP), and LiPF6. We cast thin films of these materials from solution to form simple light-emitting Received: July 12, 2021 Accepted: July 27, 2021 Leter www.acsmaterialsletters.org © XXXX American Chemical Society 1357 https://doi.org/10.1021/acsmaterialslett.1c00404 ACS Materials Lett. 2021, 3, 1357−1362 D ow nl oa de d vi a U N IV O F T E X A S A T D A L L A S on A ug us t 1 7, 2 02 1 at 1 6: 23 :0 1 (U T C ). Se e ht tp s: //p ub s. ac s. or g/ sh ar in gg ui de lin es f or o pt io ns o n ho w to le gi tim at el y sh ar e pu bl is he d ar tic le s.