Ye Dan, Li Zhijian, Chen Wenjing, Ighodalo Kester O, Xiao Peng, Chen Tao, Xiao Zhengguo
Department of Physics, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Department of Materials Science and Engineering, CAS Key Laboratory of Materials for Energy Conversion, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China.
ACS Appl Mater Interfaces. 2022 Aug 3;14(30):34918-34925. doi: 10.1021/acsami.2c07314. Epub 2022 Jul 22.
Perovskite light-emitting diodes (PeLEDs) show great potential in display and lighting because of their tunable wavelength, narrow emission bandwidths, and high color purity. Currently, the external quantum efficiency (EQE) of red and green PeLEDs has reached >23%. However, yellow PeLEDs are still rarely reported because of phase separation in mixed-halide perovskites and the coexistence of multiple phases in quasi-two-dimensional (quasi-2D) perovskites LABX ( = 1, 2, 3, ...), where L is a bulky organoammonium ligand. Here, we fabricate stable yellow PeLEDs by manipulating the phase distribution and incorporating rubidium cations (Rb) in quasi-2D perovskites. The transient absorption results confirm that alkylammonium ligand butyl ammonium (BA) has a narrower phase distribution than phenylethyl ammonium (PEA) in the quasi-2D perovskites, resulting in a more blue-shifted emission peak. We further incorporate a proper molar ratio of Rb in the (BA)CsPbI perovskite to blue-shift the emission peak to the yellow range. Finally, the yellow PeLEDs exhibit an EQE of 3.5%, and the stable emission peak is located at 595 nm. Our work provides a useful approach for the fabrication of highly efficient and stable yellow PeLEDs.
钙钛矿发光二极管（PeLEDs）因其波长可调、发射带宽窄和色纯度高而在显示和照明领域展现出巨大潜力。目前，红色和绿色PeLEDs的外量子效率（EQE）已达到>23%。然而，由于混合卤化物钙钛矿中的相分离以及准二维（准2D）钙钛矿LABX（ = 1, 2, 3, ...）中多相的共存，黄色PeLEDs的报道仍然很少，其中L是一个庞大的有机铵配体。在这里，我们通过控制相分布并在准2D钙钛矿中引入铷阳离子（Rb）来制备稳定的黄色PeLEDs。瞬态吸收结果证实，在准2D钙钛矿中，烷基铵配体丁基铵（BA）的相分布比苯乙铵（PEA）更窄，导致发射峰发生更大的蓝移。我们进一步在（BA）CsPbI钙钛矿中引入适当摩尔比的Rb，使发射峰蓝移至黄色范围。最终，黄色PeLEDs的EQE为3.5%，稳定的发射峰位于595 nm处。我们的工作为制备高效稳定的黄色PeLEDs提供了一种有用的方法。
