Journal of Luminescence 98 (2002) 237–243 Photochemical hole-burning in C 60 –H 2 TPP supramolecule doped polymer: a comparative study with the behaviour of separated H 2 TPP and C 60 entities J.H. Rice a, *, J.-P. Galaup a , K. Kordatos b , M. Prato b a Laboratoire Aim! e Cotton, B # at. 505, Universit ! e Paris-Sud, 91405 Orsay, France b Dipartimento di Scienze Farmaceutiche, Universita di Trieste, 34127 Trieste, Italy Abstract We present optical spectroscopy measurements of a supramolecular assembly C 60 –H 2 TPP in poly-vinylbutyral (PVB) and compare its photophysical properties to separated C 60 and H 2 TPP in PVB. Optical absorption and emission from the supramolecular assembly mainly appears as resulting from a superposition of the respective properties of the fullerene and porphyrin moieties. However, emission features unique to the supramolecule assembly are found and reported. Spectral hole-burning properties of the supramolecule are similar to those observed for separated C 60 and H 2 TPP. This demonstrates that the phototautomerisation induced in the porphyrin moiety and thought to be responsible for the formation of the spectral hole is largely unaffected by the presence of the fullerene. r 2002 Elsevier Science B.V. All rights reserved. Keywords: Porphyrin; Fullerene; Supramolecule; Spectral hole-burning 1. Introduction Multi-tasking materials are thought to have many possible applications in applied science, enabling a single material to perform several tasks simultaneously. Such materials can be created through the use of supramolecular assemblies that possess multiple functionalities [1]. A supramole- cule assembly can in one part possess a moiety that enables one function to be performed while another part of the molecule allows further operations to be carried out simultaneously. Optical spectroscopy is well known as a powerful tool for understanding the behaviour of electronic excitations in the solid state. Site-selective spectro- scopies are well established methods to obtain highly resolved spectra of species diluted in a solid environment at low temperatures. Persistent spec- tral hole-burning (PSHB) is observed at low temperatures where narrow homogeneous lines originating from pure electronic transitions can be revealed despite the inhomogeneous broadening arising from the statistical spread of these homo- geneous lines. The selective laser excitation within an inhomogeneously broadened band can induce changes in the absorbing molecule or in its surroundings leading to a hole in the absorption profile. PSHB has potential uses in high-density information storage and optical processing [2]. *Corresponding author. Fax: 33-1-69-35-21-00. E-mail address: james.rice@lac.u-psud.fr (J.H. Rice). 0022-2313/02/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0022-2313(02)00275-2