Outdoor Stability of Chloro–(Chloro)_n–Boron Subnaphthalocyanine and Chloro–Boron Subphthalocyanine as Electron Acceptors in Bilayer and Trilayer Organic Photovoltaics

In the field of organic photovoltaics (OPVs), outdoor stability research has lagged behind material development and device engineering. Testing protocols established at the International Summit of OPV Stability (ISOS) have stimulated some stability research, but these studies are almost exclusively limited to already-refined devices made with already-commercialized materials. If OPV materials were tested outdoors during small-scale stages, stability issues could be detected earlier in the development cycle. Chloro–(chloro)n–boron subnaphthalocyanine (Cl–ClnBsubNc) is a material with high OPV performance but has not previously been tested outdoors. An OPV power conversion efficiency of 8.4% has been previously demonstrated for a trilayer stack containing α-sexithiophene, Cl–ClnBsubNc, and chloro–boron subphthalocyanine (Cl–BsubPc). Building on the most advanced ISOS outdoor testing protocols (ISOS-O3), we assess the outdoor stability of small-scale bilayer and trilayer OPVs while establishing an improved stability screening method for future derivatives. The outdoor stability of Cl–ClnBsubNc is determined to be comparable to that of Cl–BsubPc.