High‐Brightness Blue and White LEDs based on Inorganic Perovskite Nanocrystals and their Composites |
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| Authors: | En‐Ping Yao Zhanlue Yang Lei Meng Pengyu Sun Shiqi Dong Ye Yang Yang Yang |
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| Affiliation: | 1. Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, USA;2. Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan;3. Chemistry and Nanoscience Science Center, National Renewable Energy Laboratory, Golden, CO, USA |
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| Abstract: | Inorganic metal halide perovskite nanocrystals (NCs) have been employed universally in light‐emitting applications during the past two years. Here, blue‐emission (≈470 nm) Cs‐based perovskite NCs are derived by directly mixing synthesized bromide and chloride nanocrystals with a weight ratio of 2:1. High‐brightness blue perovskite light‐emitting diodes (PeLEDs) are obtained by controlling the grain size of the perovskite films. Moreover, a white PeLED is demonstrated for the first time by blending orange polymer materials with the blue perovskite nanocrystals as the active layer. Exciton transfer from the blue nanocrystals to the orange polymers via Förster or Dexter energy transfer is analyzed through time resolved photoluminescence. By tuning the ratio between the perovskite nanocrystals and polymers, pure white light is achieved with the a CIE coordinate at (0.33,0.34). |
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| Keywords: | light‐emitting diodes nanocrystals perovskites white light |
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