The hydrothermal synthesis of blue-emitting boron-doped CQDs and its application for improving the photovoltaic parameters of organic solar cell.

In this work, boron-doped CQDs (B-CQDs) were synthesized by using boric acid, urea, and citric acid via hydrothermal method to use as a novel additive material for poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) based organic solar cells. The OSCs with an inverted device structure were fabricated on titanium dioxide (TiO 2 ) thin film. It was showed the crystallinity, morphological and optical properties of P3HT:PCBM films improved after B-CQDs additive. The best performance was obtained to be a 39.65% of FF, a 546 mV of V oc , an 8.606 mA cm -2 of J sc after 3 vol.% B-CQDs addition in P3HT:PCBM blend. The power conversion efficiency (PCE) enhanced from 1.72% (non-doped device) to 2.33% (3% of B-CQDs) (a ~ 35% increase). The obtained results provided that B-CQDs are promising materials to improve the performance of solar cell applications. The novelty of this work is to improve the performance of OSCs using cost-effective and eco-friendly Boron CQDs as an additive. Besides, to achieve a good PCE of OSCs, it is necessary for utilized clean and green energy.