Improved performance from organic bulk heterojunction (BHJ) solar cells composed of a blend of chloroaluminum phthalocyanine (ClAlPc) and fullerene C70 is demonstrated. The deep highest occupied molecular orbital of ClAlPc and the broad absorption of C70 lead to a high open-circuit voltage and a high short-circuit current density (JSC). A change in the intermolecular arrangement of ClAlPc is observed when the substrate is heated to 370-390 K during deposition of the blend layer, indicating the growth of π-stacked nanocrystals of ClAlPc. Consequently, JSC and the fill factor are enhanced significantly, and a high power conversion efficiency of 4.1% is obtained.
All Science Journal Classification (ASJC) codes