Wang Yimeng, Guo Shanshan, Yan Xiaolian, Yang Xinyu, Yu Junhong, Liu Haitao, Dang Cuong
School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, Singapore, 50 Nanyang Avenue, Singapore, 639798 Singapore.
Nanotechnology. 2020 Aug 21;31(34):345706. doi: 10.1088/1361-6528/ab92c9. Epub 2020 May 13.
Colloidal perovskite CsPbX (X = Cl, Br, I) nanocrystals (CPNCs)/polymers composites have attracted extensive attention due to their potential to be developed as flexible phosphor films for lighting applications. However, to maintain high quantum efficiency and photo stability of CPNCs in such composites remains a daunting challenge. Here, we have demonstrated a layered composite structure consisting of CPNCs and polydimethylsiloxane (PDMS) with multi-color emission and long-term stability. By tuning the molar ratio between CsPbClBr and CsPbBrI, flexible fluorescent films as down-converter layers with a high luminescent efficiency and a controllable color temperature spanning from 3194 K to 5901 K have been demonstrated. Furthermore, due to embedding inside such composites, the quantum efficiency of CPNCs exhibited negligible changes during seven months in ambient conditions. The carrier dynamics based on time-resolved photoluminescence (PL) and transient absorption spectroscopy reveal that the hot electron tunneling and trapping process are significant in the composite film. This work provides a good understanding of CPNC materials in complex composite for the development of flexible, robust, color controllable fluorescent films for lighting applications.
胶体钙钛矿CsPbX（X = Cl、Br、I）纳米晶体（CPNCs）/聚合物复合材料因其有望被开发为用于照明应用的柔性磷光体薄膜而备受关注。然而，在这类复合材料中保持CPNCs的高量子效率和光稳定性仍然是一项艰巨的挑战。在此，我们展示了一种由CPNCs和聚二甲基硅氧烷（PDMS）组成的具有多色发射和长期稳定性的层状复合结构。通过调节CsPbClBr和CsPbBrI之间的摩尔比，已证明了具有高发光效率和3194 K至5901 K可控色温的柔性荧光薄膜作为下转换层。此外，由于嵌入在这类复合材料中，CPNCs的量子效率在七个月的环境条件下变化可忽略不计。基于时间分辨光致发光（PL）和瞬态吸收光谱的载流子动力学表明，热电子隧穿和俘获过程在复合薄膜中很重要。这项工作为开发用于照明应用的柔性、坚固、颜色可控的荧光薄膜提供了对复杂复合材料中CPNC材料的良好理解。
