Photovoltaic properties of BiI₃ with copper interstitials

Abstract

The synthesis and photovoltaic effect of Cu₃ₓBi₁₋ₓI₃ (CBI) thin films were studied. Although CBI was originally inspired by the material class of Caswellsilverites (also known as Rudorffites), a XRD study showed that its crystal structure resembles a BiI₃-cage with interstitial copper. CBI was found to demonstrate optoelectronic properties suitable for solar light harvesting, including a band gap of 1.66 eV and thermal stability up to 333 °C. The corresponding thinfilm solar cells achieved a peak power conversion efficiency of 0.65%.