Size and bandgap tunability in Bi2S3 colloidal nanocrystals and its effect in solution processed solar cells

Abstract

We report the synthesis and full characterization of colloidal Bi₂S₃ nanocrystals with different sizes, showing a band gap variation up to 0.2 eV and pointing to quantum confinement effects. Polymer–nanocrystal solar cells have been fabricated to study the effect of the size and band gap change on the performance of the devices. We have found that smaller nanocrystals present a much higher V_oc, pointing to a system with a reduced density of surface traps.