Andrea Crovetto1,2,3,Thomas Unold3,Andriy Zakutayev2
Technical University of Denmark1,National Renewable Energy Laboratory2,Helmholtz-Zentrum Berlin für Materialien und Energie3
Andrea Crovetto1,2,3,Thomas Unold3,Andriy Zakutayev2
Technical University of Denmark1,National Renewable Energy Laboratory2,Helmholtz-Zentrum Berlin für Materialien und Energie3
Certain phosphorus-containing III-V semiconductors (GaP, InP and related alloys) are among the best-performing PV absorbers. Yet, there is hardly any other phosphide material that has received extensive attention for applications in PV or optoelectronics in general. Exciting progress has been reported within the family of Zn-based phosphide compounds (Zn<sub>3</sub>P<sub>2</sub>, ZnGeP<sub>2</sub>, ZnSnP<sub>2</sub> etc.), but high PV efficiencies are yet to be demonstrated.<br/><br/>In this contribution, I will discuss a radically different class of semiconductors that is quite unique to phosphides. They can be referred to as “P-rich phosphides”. In stark contrast to almost any other compound semiconductor previously investigated for PV applications, P-rich phosphides contain bonds between nonmetallic atoms (in their specific case, phosphorus-phosphorus bonds).<br/><br/>Due to their distinct bonding mechanisms, phosphorus-rich phosphides give us an opportunity to find new materials design routes for high-efficiency PV, potentially overcoming some of the design limitations of “standard” semiconductor featuring only metal-nonmetal bonds.<br/>I will present the first successful thin-film synthesis [1] of any polycrystalline P-rich phosphide. The synthesized material is CuP<sub>2</sub>, which is a 1.5 eV band gap semiconductor with strong optical absorption and native p-type doping in an attractive range for thin-film heterojunction solar cells.<br/><br/>Finally, I will highlight a recent computational screening study [2], in which five P-rich phosphides were identified as highly promising materials for PV. These new materials are still awaiting thin-film synthesis.<br/> <br/>[1] Crovetto et al. Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP<sub>2</sub>. <i>J. Am. Chem. Soc.</i> <b>2022</b>, <i>144</i>, 13334–13343.<br/>[2] Kangsabanik et al. Indirect Band Gap Semiconductors for Thin-Film Photovoltaics: High-Throughput Calculation of Phonon-Assisted Absorption. <i>J. Am. Chem. Soc.</i> <b>2022</b>. Available online. https://doi.org/10.1021/jacs.2c07567.