Tin naphthalocyanine complexes for infrared absorption in organic photovoltaic cells

In this work, we examine the optical properties of tin naphthalocyanine dichloride (SnNcCl2), and its performance as an electron donor material in organic photovoltaic cells (OPVs). As an active material, SnNcCl2 is attractive for its narrow energy gap which facilitates optical absorption past a wavelength of λ = 1100 nm. We demonstrate a power conversion efficiency of ηP = (1.2 ± 0.1)% under simulated AM1.5G solar illumination at 100 mW/cm2 using the electron donor–acceptor pairing of SnNcCl2 and C60 in a bilayer device architecture. While some phthalocyanines have been previously used to improve infrared absorption, this is often realized through the formation of molecular dimers. In SnNcCl2, the infrared absorption is intrinsic to the molecule, arising as a result of the extended conjugation. Consequently, it is expected that SnNcCl2 could be utilized in bulk heterojunction OPVs without sacrificing infrared absorption.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Examined tin naphthalocyanine dichloride as an infrared absorber in organic photovoltaics. ► Performance is superior to tin phthalocyanine, an archetypical infrared small molecule donor. ► Absorption extends beyond a wavelength of 1100 nm in both neat and mixed films.