Organic Photovoltaic Cells Using Group 10 Metallophthalocyanine Electron Donors

Abstract

Organic planar heterojunction solar cells using as an electron acceptor and group 10 metal phthalocyanines (nickel, palladium, and platinum) as electron donors have been fabricated and evaluated for their device characteristics. Upon changing the metal center, these devices exhibit interesting trends, such as variations in the open-circuit voltage, short-circuit current density, and power-conversion efficiency. Devices based on palladium phthalocyanine (PdPc) exhibited the best performance, achieving power-conversion efficiencies of 2.4% under AM1.5G ( ) illumination. This is due to the higher ionization potential of PdPc and greater efficiency of charge photogeneration. Nickel phthalocyanine (NiPc) has the highest hole mobility, but cells using NiPc have the weakest charge-generation efficiency. This is due to poor exciton diffusion to the organic heterojunction that can be overcome by using a composite NiPc: charge-generation layer. An optimized NiPc-based cell has a power-conversion efficiency of 1.9%.