Spectral hole burning and electron–phonon coupling in aluminum phthalocyanine tetrasulfonate doped inorganic hosts with and without water addition

The earlier discovery by G.J. Small and his group of the exceptional hole burning properties of aluminum phthalocyanine tetrasulfonate (AlPT) in hyper quenched water encouraged us to look for other suitable hosts in which such properties could be preserved. The non-photochemical hole burning behavior of AlPT in various hosts: dense inorganic or hybrid xerogels, light aerogels and porous Vycor glasses soaked with dye-doped water is investigated. The crucial role played by water or the silanol groups in xerogel pores is underlined by our experiments, the hole burning efficiency becoming quite low in a hybrid xerogel or in a dried porous glass.