Triphenylamine‐Derived Solid‐State Emissive Carbon Dots for Multicolor High‐Efficiency Electroluminescent Light‐Emitting Diodes

Fluorescent carbon dots (CDs) have emerged as fantastic luminescent nanomaterials in electroluminescent light-emitting diodes (LEDs). However, the device performance of the reported CDs-based electroluminescent LEDs is far from satisfactory due to the serious aggregation-caused quenching of CDs. Here, inspired by the nonplanar structure and good carrier mobility of triphenylamine unit, two kinds of triphenylamine-derived solid-state emissive CDs with orange and yellow color are facilely synthesized through a solvothermal treatment. Theoretical calculations show that the triphenylamine structure could greatly inhibit the direct π-π* stacking of aromatic skeletons and enhance the fluorescence properties of CDs in aggregation state. Delightedly, both the two CDs show strong solid-state fluorescence, excellent solution-processability, good film-forming ability, and high electron/hole mobility. More interestingly, by adopting the obtained CDs as single emissive layer, high-performance orange-color and green-color LEDs are successfully fabricated, with maximum brightness of 9450/4236 cd/m2, high current efficiency of 1.57/2.34 cd/A and low turn-on voltage of 3.1/3.6 eV are respectively achieved. Significantly, white-color LED device with a CIE coordinate of (0.30, 0.39), maximum brightness of 5726 cd/m2 and low turn-on voltage of 3.0 eV is further prepared. This work provides a universal platform for the construction of novel solid-state emissive CDs with significant applications in photoelectric device.