Spectroscopy and Photochemistry of meso-Diphenyltribenzonaphthoporphyrin at Low Temperatures: A Novel System for Hole-Burning Applications

Abstract

We present a custom-tailored material for the application of spectral hole-burning in optical storage and imaging spectroscopy. The photoactive molecule meso-diphenyltribenzonaphthoporphyrin (P2TriBNP) combines the advantages of chlorins and simple porphyrins used so far, namely, the spectral separation between photoeduct and photoproduct states and a high photochemical hole-burning yield. Basic characteristics of the material were measured. We obtained the values of 3.2 ± 1.5% for the hole-burning yield, of ∼0.6 for the Debye−Waller factor in poly(vinyl butyral) (PVB), and a spectral separation between the educt and product absorption of 120 cm-1. The difference in the dipole moment between the ground and the excited state shows two contributions. The permanent dipole moment difference has a value of 0.29 ± 0.03 D. A root mean square value of 0.15 ± 0.02 D for a distributed, matrix-induced component was measured. Because of their high photochemical yields and the large absorption cross sections, P2TriBNP and similar compounds open the way for a new class of experiments dealing with lower light intensities and shorter exposure times than before. However, we observed the lifetime of narrow spectral holes to be limited to several hours. Nevertheless, the material exhibits a high potential for the application in imaging spectroscopy, e.g., the simultaneous recording of spatial and spectral information of astronomical objects.