Interlayer energy transfer between perylene diimide and phthalocyanine monolayers

Interlayer energy transfer from perylene diimide (PDI12) layers to phthalocyanine layers was studied using steady-state absorption, fluorescence, and time-resolved fluorescence and microscopy methods. The layers were prepared by Langmuir-Schäfer method, spaced by a few layers of octadecylamine deposited by Langmuir-Blodgett method, when required. The fluorescence lifetime microscopy method allowed to exclude defects from the energy transfer analysis and calculate the fluorescence lifetimes of PDI12 for the defect free areas. The estimated distance dependence of the interlayer energy transfer follows roughly second order dependences on the distance with the critical distance of 6.9. nm.