Lian Fei, Wang Chuanxi, Wu Qian, Yang Minghui, Wang Zhenyu, Zhang Chi
Institute of Environmental Processes and Pollution Control, School of Environmental and Civil Engineering, Jiangnan University Wuxi 214122 China
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs Tianjin 300191 China.
RSC Adv. 2020 Jan 7;10(3):1281-1286. doi: 10.1039/c9ra06729a.
Multi-color-emissive fluorescent polymer nanocomposite films have potential applications in optoelectronic devices. Herein, stretchable, mechanically stable multi-color carbon-dots-based films are fabricated by condensation and aging of carboxylated polyurethane in the presence of various carbon sources. As-prepared CDs/PU films emit different colors covering from blue (414 nm) to red (620 nm) by tuning reaction conditions. Moreover, CDs are fixed and have good dispersion in the PU matrix due to the interactions of amine groups from the carbon sources with the carboxylate group of PU. Thus, phase separation of composite films can be avoided. And, more than 90% of their emission intensity is preserved after soaking in water for 30 days, aging for up to 6 h at 100 °C, and subjecting to several cycles of stretching and natural recovery. These advantages are encouraging for the use of CDs/PU composite films in solid-state lighting applications. Remote multi-color LEDs have been fabricated by placing a down-conversion layer of CDs/PU films separated through coating them on the same chips (emission at 365 nm), with Commission Internationale de l'Eclairage color coordinates of (0.22, 0.23), (0.43, 0.53), (0.49, 0.46), and (0.41, 0.28), respectively.
多色发射荧光聚合物纳米复合薄膜在光电器件中具有潜在应用。在此，通过在各种碳源存在下使羧化聚氨酯缩合和老化，制备了可拉伸、机械稳定的多色碳点基薄膜。通过调节反应条件，所制备的碳点/聚氨酯薄膜发出从蓝色（414纳米）到红色（620纳米）的不同颜色。此外，由于碳源中的胺基与聚氨酯的羧酸根基团之间的相互作用，碳点被固定且在聚氨酯基质中具有良好的分散性。因此，可以避免复合薄膜的相分离。并且，在水中浸泡30天、在100℃下老化长达6小时以及经过多次拉伸和自然恢复循环后，它们的发射强度保留超过90%。这些优点对于碳点/聚氨酯复合薄膜在固态照明应用中的使用是令人鼓舞的。通过在同一芯片（发射波长为365纳米）上涂覆分离的碳点/聚氨酯薄膜的下转换层，制备了远程多色发光二极管，其国际照明委员会色坐标分别为(0.22, 0.23)、(0.43, 0.53)、(0.49, 0.46)和(0.41, 0.28)。
