Abstract:

The energy level of the electron acceptor plays an important role in bulk heterojunction solar cells. A conjugated polymer BTT-BT_z  as electron donor and fullerene derivatives PC₇₀BM, PC₆₀BM and IC₆₀BA as acceptor with different energy levels was studied, and the influence of the acceptor energy level on the opencircuit voltage (V_oc) , shortcircuit current density (J_sc), fill factor (FF) and power conversion efficiency (PCE) were investigated. The BTTBTz/IC₆₀BA based device exhibited a high V_oc of 1.06 V, but the poor PCE of 1.49% due to the lower J_sc. Although the V_oc of the devices based on BTTBTz/PC₆₀BM and BTTBTz/PC₇₀BM is decreased, they displayed promising efficiencies of 322% and 5.06%.

Key words: solar cell, copolymer； bulkheterojunction