In this paper, a unique strategy is proposed to modulate fluorescence color of carbon dots (CDs) under both aqueous solution and solid state for bright multicolor light-emitting diodes (LEDs) applications. We report facile synthesis of dual-peak-emissive CDs with self-quenching-resistant character under solid state through hydrothermal method, and investigate the origins of dual-peak emission for the first time. In addition, based on the unique dual-peak-emissive phenomenon, acid-mediated PL behaviors were realized by changing the pH value of hydrothermal precursors. We realized the color-tunable fluorescence under aqueous solution from blue (B-CDs) to yellow-green (YG-CDs) color and solid state from yellow to orange-red color. The changed PL behaviors are attributed to the more conjugated structure inside CDs due to elevated carbonization degree. Furthermore, the red-shifted fluorescence from aqueous solution to solid state is ascribed to supramolecular cross-linking between adjacent particles. Thus, by manipulating the supramolecular cross-linking degree of YG-CDs in PVA, a series of luminescent blue-shifted CDs/PVA composite phosphors were obtained. Finally, we fabricate the almost full-color and white color LEDs with decent performances, which indicate their potential for solid-state lighting applications.

中文翻译：

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彩色可调碳点具有全色发光二极管应用的固态发射

在本文中，提出了一种独特的策略来调节水溶液和固态状态下碳点（CD）的荧光颜色，以用于明亮的多色发光二极管（LED）应用。我们报道了通过水热法在固态下容易合成具有抗自猝灭特性的双峰发射性CD，并首次研究了双峰发射的起源。此外，基于独特的双峰发射现象，通过改变水热前体的pH值可以实现酸介导的PL行为。我们实现了水溶液在从蓝色（B-CDs）到黄绿色（YG-CDs）颜色以及从黄色到橙红色的固态下的颜色可调荧光。PL行为的改变归因于CD内碳化程度的提高，从而使CD内部的共轭结构更加紧密。此外，从水溶液到固态的红移荧光归因于相邻颗粒之间的超分子交联。因此，通过控制PVA中YG-CD的超分子交联度，获得了一系列发光的蓝移CD / PVA复合磷光体。最后，我们制造出性能几乎令人满意的几乎全色和白色的LED，这表明它们在固态照明应用中的潜力。