Emerging Cu-Based Phosphides as Contacts and Absorbers for Solar Energy Conversion

Many new contact and absorber materials have been studied in the past decade for solar energy conversion applications. For example, research into emerging chalcogenides expanded from zincblende-derived CdTe, CuInSe₂ and Cu₂ZnSnS₄ to include non-tetrahedrally bonded compounds like 1D-bonded Sb₂S₃, layered CuSbS₂ chalcostybites, or BaZrS₃ perovksites.<br/><br/>There are much fewer known phosphide solar materials, besides II-IV-P₂ derivatives of GaP (e.g. ZnSnP₂, ZnSiP₂) and their binary constituents (e.g. Zn₃P₂) studied as absorbers, or wide band gap bipolar dopable BP that has been considered for contact applications. Nevertheless, the reported semiconductor properties and initial device performances of phosphide materials are quite promising and deserve further research attention.<br/><br/>This presentation will highlight a few emerging phosphide materials based on Cu, as potential transparent contact and light absorber layers in solar energy conversion devices. The first example is experimental demonstration of high electrical conductivity and measurement optical transparency in theoretically predicted CaCuP sputtered thin film material [1]. The second example is two-step synthesis and semiconductor property measurements of CuP₂ – one of the first known phosphorus-rich semiconductors in thin film form [2].<br/><br/>General synthesis and characterization challenges associated with doing experiments on the phosphide class of materials will be also discussed.<br/><br/>[1] Chem. Sci. 13, 5872 (2022)<br/>[2] J. Am. Chem. Soc. 144, 13334 (2022)