Pentacene-Based Dendrimers: Synthesis and Thin Film Photoconductivity Measurements of Branched Pentacene Oligomers

The synthesis of pentacene-based dendrimers has been achieved via esterification of 1,3,5-benzenetricarboxylic acid and unsymmetrical pentacene 4 possessing a hydroxy group. Dendrimers 1 (C₁₈₃H₂₀₄O₉Si₉, 2800 g mol⁻¹) and 2 (C₅₄₀H₅₇₀O₃₀Si₂₄, 8214 g mol⁻¹) are characterized by ¹H and ¹³C NMR, IR, UV−vis, and fluorescence spectroscopy, as well as mass spectrometry. These branched oligomeric materials are benchtop stable and soluble in common organic solvents, allowing for solution cast formation of thin films. Photocurrent and photocurrent yield measurements of these films reveal improved efficiency in photogenerated conduction for dendrimers in comparison to linearly connected pentacene-based polymers.