Multicolor Graphene Quantum Dots via Solvatochromic Tuning and Sulfur Doping for Light-Emitting Diodes
Yongsheng Yang, Changxing Wang, Siyuan Tang, Da Chen, Xiameng Li, Peng Zhao, Chenjie Gu
Abstract
Recently, graphene quantum dots (GQDs) with polychrome emission capability have attracted much attention due to their multifarious applications. In this study, we report a facile and green approach for rapid preparation of multicolor emission GQDs. Experimentally, UV light was used to drive the low-temperature synthesis, and a tunable emission wavelength of the GQDs was achieved through the synergistic effect of solvatochromic tuning and sulfur doping. Results show that multicolor emission wavelengths of green-GQDs (G-GQDs) from blue to yellow are obtained by simply controlling the polarity of the surrounding solutions. Moreover, red-GQDs with the emission wavelengths extended from green to red are further obtained by sulfur doping. Thereafter, G-GQDs were used to develop a trace water-detecting platform, ascribed to the high sensitivity of water-quenchable fluorescence, and a low detection limit of 0.061% was achieved. Meanwhile, based on the outstanding multicolor tunability of as-prepared GQDs, we successfully manufactured multicolor solid fluorescence films to fabricate multicolor light-emitting diode (LED) devices. Furthermore, high-quality white LEDs (WLEDs) are fabricated with the CIE coordinates of (0.341, 0.354) and a color temperature of 5161 K. This study highlights the potential of GQDs in various applications, including solid-state fluorescence films, optoelectronics, and optical molecular sensing.