Reverse saturable absorption in palladium and zinc tetraphenyltetrabenzoporphyrin doped xerogels Original Research Article

Solid-state inorganic matrices (xerogels) doped with tetraphenyltetrabenzoporphyrins of Pd and Zn (PdTPTBP and ZnTPTBP) have been prepared using the sol-gel process. Nonlinear reverse saturable absorption was observed for both materials when they were illuminated with nanosecond laser pulses at 532 nm. PdTPTBP doped xerogels exhibit nonlinear activation thresholds of about 10 mJ/cm2, which is much lower than the value of 80 mJ/cm2 obtained under similar conditions for Al phthalocyanine chloride. The experimental results are discussed using classical 4 energy level diagrams.