Photochromic Polymer Composites for Two-Photon 3D Optical Data Storage

摘要

In this paper we demonstrate 3D two-photon recording and two-photon readout in photochromic polymer composites containing a mixture of 1,2-bis(2-methylbenzo[b]thiophen-3-yl)hexafluorocyclopentene(diarylethene 1)and fluorene derivatives 2,2'-(9,9-didecyl-9H-fluorene-2,7-diyl)bis(ethene-2,1-diyl)bis-(4,1-phenylene))dibenzo[d]thiazole(2)or poly(9,9-didecyl-2,7-dipheylaminofluorene)(3).The recording mechanism in this system is based on two-photon excitation of the closed form of diarylethene 1 at 800 nm.The readout mechanism is based on the modulation of the emission intensity of fluorene derivatives 2 or 3 by the closed form of diarylethene 1 through Resonance Energy Transfer(RET).Foster distances(R_0)and critical concentrations(A_0)were calculated from the spectral overlap of the donor's emission(fluorene derivatives)and the acceptor's absorption(closed form of diarylethene 1)in solution and in polymer films of PMMA-co-VBP.This system was demonstrated to be suitable for recording data by two-photon excitation in thick storage media.The RET-based readout method proved to be essentially nondestructive(exhibiting a loss of the initial fluorescence emission less than 20% of the initial emission after 10 000 readout cycles),providing a solution to a long-standing challenge in photochromic optical data storage.