Carbon dots promote the carrier recombination in Poly (9-vinyl carbazole) to enhance its electroluminescence

Carbon dots (CDs) are one species of multifunctionally auxiliary materials with promising application in photoelectrocatalyst and photoelectrodevices. However, there are few reports on enhancing the electroluminescence (EL) of materials by CDs and the effects of CDs on the charge transport dynamics have not been revealed so far. Herein, CDs are firstly successful to be applied in the enhancement of EL of Poly (9-vinyl carbazole), which is set as model material for research, abbreviated as PVK with the EL wavelength of 432 nm. The brightness of CDs enhanced PVK LEDs reaches 176 cd m(-2) that obviously 54.3 % higher than that of pure PVK based LEDs and other parameters are all improved. The Commission Internationale d'Eclairage coordinates of CDs enhanced PVK LEDs are situated at (0.17, 0.10). Notably, through the transient photovoltage technology and method of empirical mode decomposition, the mechanisms of charge transport dynamics between CDs and PVK molecules are determined. This work paves a new direction for the improvement of the luminescent properties of electroluminescent devices and a new mentality to understand the effects of CDs on charge transport in the EL process.