Synthesis, optical, electrochemical properties and photovoltaic performance of novel panchromatic meso-thiophene BODIPY dyes with a variety of electron-donating groups at the 3,5-positions

Abstract

A series of novel BODIPY derivatives (BDP1–5) containing a thiophene motif at the meso-position and various electron-donating units at the 3,5-positions were designed and synthesized. With the extended D–A–D conjugated skeleton, these dyes exhibit effective panchromatic absorption with maximum extinction coefficients over 1.4 × 10⁵ M⁻¹ cm⁻¹ in solution state and dramatically higher values in the film state. Suitable HOMO/LUMO energy levels, around −5.4 eV and −3.8 eV, respectively, vs. PCBM combined with the good solubility and perfect film-forming ability make them attractive for BHJ solar cell applications. The photovoltaic device based on BDP2 and PC₆₁BM exhibits a potential power conversion efficiency of 2.12%, a moderate open-circuit voltage of 0.73 V and a relatively high short-circuit current density of 7.64 mA m⁻².