Lutetium Bis(2,3,9,10,16,17,23,24-octafluorophthalocyanine): From Synthesis to Heterojunction Device

Lutetium bisphthalocyanine (LuPc₂) is a well-established molecular semiconductor, yet its fluorinated derivatives remain largely unexplored. In this work, we investigate the lutetium octafluorosubstituted bisphthalocyanine complex, Lu(F₈Pc)₂. The complex was synthesized both directly from 4,5-difluoro-1,2-dicyanobenzene and via the metal-free octafluorophthalocyanine precursor H₂F₈Pc, and characterized by mass spectrometry and optical spectroscopy. Drop-cast films of Lu(F₈Pc)₂ were fabricated and their electrical properties evaluated. Additionally, we examined the response of these resistors to ammonia. Bilayer heterojunctions combining Lu(F₈Pc)₂ with its nonsubstituted analogue, LuPc₂, were also prepared. Notably, Lu(F₈Pc)₂ resistors and Lu(F₈Pc)₂/LuPc₂ heterojunctions exhibit opposite responses to NH₃, positive and negative, respectively. These findings provide new insights into structure-property relationships in phthalocyanine-based semiconductors.