Preparation, Characterization, and Photoelectrochemistry of Langmuir−Blodgett Films of the Endohedral Metallofullerene Dy@C82 Mixed with Metallophthalocyanines

Abstract

Stable Langmuir−Blodgett films of the endohedral metallofullerene Dy@C82 mixed with metallophthalocyanine (MPc = copper tetra-tert-butylphthalocyanine (1) and M octakis(octyloxy)phthalocyanine, M = copper (2) and zinc (3)) are fabricated from the N2/water interface at a molar ratio of 1:1. Optical, electrochemical, and photoelectrochemical properties of these films have been studied. The packing of Dy@C82/MPc is found to be dependent on the substituents and the central metal ion of MPc, resulting in different relative orientations of the MPc's macrocyclic ring plane and the metallofullerene ball in the Langmuir films. Steady anodic photocurrent responses have been demonstrated for the Dy@C82/MPc mixture films with enhanced quantum yields compared to the pure forms of both MPc and Dy@C82. Dy@C82/2 (or 3) are shown to outperform Dy@C82/1, giving quantum yields up to 7−8% under appropriate conditions. Both ground-state charge transfer and photoinduced charge transfer between Dy@C82 and the octasubstituted MPcs 2 and 3 are proposed. Comparative studies with C60 have also been conducted.