Study on the influence of embedded structure of carbon quantum dots of the organic solar cells with the territory active layer structure of P3HT: PC61BM: CQDs

Abstract

In this work, carbon quantum dots (CQDs) were inserted into the poly(3-hexylthiophene):(6,6)-phenyl-C61 butyric acid acrylic (P3HT:PC61BM) system as the third component. Therefore, organic solar cells (OSCs) based on the ternary active layer structure of P3HT:PC61BM:CQDs were prepared. The lattice distance of CQDs was performed using transmission electron microscopy (TEM). The excellent fluorescence emission and light absorption of CQDs were characterized by photoluminescence (PL) and UV–vis absorption spectra. The characterization results of atomic force microscope (AFM) and electrochemical impedance spectroscopy (EIS) indicate that the introduction of CQDs in the active layer can improve the performance of the device but not significantly change the properties of the film. The device based on P3HT:PC61BM:CQDs ternary structure obtains a power conversion efficiency (PCE) of 3.32%, which has a 32.8% increase compared to the reference device (2.50%). Besides, the best short-circuit current density attends to 18.9 mA/cm2, which is increased by 25% compared to the reference device. The improvement is attributed to the photoluminescence effect and the multiple exciton generation (MEG) effect of CQDs. This work provides a new method to improve the performance of organic solar cells.