Giant Bulk Photovoltaic Effect in Vinylene-Linked Hybrid Heterocyclic Polymer

The bulk photovoltaic effect refers to the generation of a steady photocurrent from a homogeneous noncentrosymmetric material. It offers an alternative to the traditional p–n junction-based photovoltaic mechanism to directly convert sunlight to electricity. In this work, we investigate the bulk photovoltaic effect in low-dimensional polar organic materials with first-principles density functional theory calculations and shift current theory. With a strategy designed to break the inversion symmetry along the polymer chain, we demonstrate that conjugated vinylene-linked hybrid heterocyclic polymers can produce a strong bulk photovoltaic response to light, outperforming benchmark inorganic materials. The high current density results from the delocalized wave functions, composed mainly of carbon p orbitals. The great structural and electronic flexibility of polymers offers a robust paradigm to enhance the shift current response through chemical and physical modifications. The development of polymer blends wit...