Characterization of µ-oxo-(BsubPc)2 in Multiple Organic Photovoltaic Device Architectures: Comparing against and Combining with Cl-BsubPc.

We demonstrate the first application of a unique boron subphthalocyanine (BsubPc) derivative, the oxygen bridged dimer µ-oxo-(BsubPc)2, as a multifunctional material within planar heterojunction organic photovoltaic (OPV) devices. We first explored the pairing of µ-oxo-(BsubPc)2 with well-known electron accepting and electron donating materials to explore its basic functionality. These preliminary device structures and metrics indicated that µ-oxo-(BsubPc)2 is best applied as an electron donating material when used in simple bilayer structures, as it yielded comparable OPV device efficiencies to that of the more well-established and highly optimized chloro-boron subphthalocyanine (Cl-BsubPc) OPV device structures. Thereafter we established that the HOMO/LUMO energy levels of µ-oxo-(BsubPc)2 are well-placed to apply it as a bifunctional donor/acceptor interlayer material in both energy and charge cascade OPV device architectures. Within this context, we found that µ-oxo-(BsubPc)2 was particularly effective in a charge cascade device as an interlayer between Cl-BsubPc and C70. We finally found evidence of an alloying-like effect for devices with mixed electron donor layers of (Cl-BsubPc) and µ-oxo-(BsubPc)2, achieved through co-deposition. The overarching conclusion is therefore that µ-oxo-(BsubPc)2 has the ability to improve the performance of Cl-BsubPc OPV devices and is a multifunctional material worthy of further study.