Synthesis Of Fullerene Derivatives As Acceptors For Polymer Solar Cells

Polymer fullerene solar cells have attracted wide interests due to their simple preparation process,low cost,light weight and flexibility.In this paper,we initially optimized the synthesis and isolation process of fullerene C60,and then prepared three fullerene derivatives using the as-prepared fullerene C60.Finally,we studied the solar cell properties of these derivatives and P3HT blends.A non-HPLC method for fullerene purification was proposed.The purity of C60 can reach above 95%by Soxhlet extraction,and 97%after recrystallization with o-xylene.To further increase the purity to 99.95%,DBU was added to the recrystallization product to remove residual C70 and trioctylphosphine to eliminate oxides of fullerene C60.We optimized the synthesis conditions of[60]PCBM,and prepared two novel fullerene bisaddition derivatives bearing two naphthalene rings via traditional D-A reaction.These synthesized products were characterized by IR,NMR and MS spectroscopy and blended with P3HT for solar cell measurement.The LUMO energy level of 1,2NCBA is 0.11 eV higher than that of PCBM.As expected,It was proved that 1,2NCBA was a promising fullerene acceptor material with Voc of 0.87 V,Jsc of 9.18 mA/cm2 and FF of 0.679.The PCE of P3HT:1,2NCBA-based PSCs reached 5.03%.While the PCE of P3HT:2,3NCBA-based PSCs is much lower than P3HT:PCBM-based PSCs for the reason that the blend of 2,3NCBA and P3HT is disordered,thus leading to a very low Jsc.