Solid-state N,P-doped carbon dots conquer aggregation-caused fluorescence quenching and couple with europium metal-organic frameworks toward white light-emitting diodes

As a newly discovered photoluminescent material, carbon dots (CDs) have shown promising performance in many fields. However, due to aggregation-caused fluorescence quenching, most of CDs are poorly emissive in the solid state, which severely restricts their wide applications, especially in the optoelectronic devices . To overcome this problem, herein, we design a novel kind of self-quenching-resistant N , P -doped CDs, using polyethyleneimine (PEI), phosphoric acid , and ethanol as raw ingredients. The as-synthesized CDs are amorphous and contain abundant surface PEI chains which properly separate the individual carbon core and prevent the direct π–π interaction. Such a unique structure conquers self-quenching during aggregation, and gives CDs a bright blue fluorescence in solid state without any other additional matrices. By taking advantage of their excellent optical properties , the CD powers, combined with red emissive europium metal-organic frameworks, are successfully employed as hybrid phosphors for construction of white light-emitting diodes exhibiting a Commission Internationale de L'Eclairage (CIE) coordinate of (0.33, 0.33).