Amphiphilic Carbon Dots with Excitation‐Independent Double‐Emissions

Abstract Developing total carbon‐based multicolor emissive carbon dots (Cdots), especially amphiphilic Cdots (A‐Cdots) with several luminescent bands and limited emissive sites, is still a challenge. Herein, A‐Cdots with bright excitation‐independent blue/yellow photoluminescence (PL) bands from two types of fluorophores are synthesized by the solvothermal treatment of citric acid and dodecylamine in cyclohexane (c‐hexane) solution. Due to the hydrogen‐bonding interaction of carboxylic groups linked with A‐Cdots and the hydrophobic effects of long‐chain alkyl groups, assemblies of A‐Cdots with reversed micelle‐like structure formed in c‐hexane solution lead to remarkable yellow‐PL (y‐PL) with quantum yield of 33.1%. Time‐resolved fluorescence and the distinct solvation effects of A‐Cdots conclude that the blue‐PL and y‐PL are from the radiative recombination of emissive sites of amide and carboxylic groups. For the solvent‐dependent optical properties and the amplification effect of dual‐color PL, the A‐Cdots exhibit good potential in the very sensitive detection of trace impurities in alkane solution, such as ethanol in c‐hexane with content as low as 0.033% (v/v). With A‐Cdots as phosphors, white‐light‐emitting diodes (WLEDs) are successfully constructed with luminous efficiency of 52.72 lm W⁻¹. This work provides a new thinking for the design of multicolor luminous Cdots materials and their potential applications.