I–III–VI2 chalcopyrite compounds (I = Cu or Ag; III = Al, Ga, or In; VI = S, Se, or Te) are attractive candidates [6], [7], [8], [9], [10], [11], [12] and [13] for photocathodes in PEC systems because of their high optical
BYL719 coefficients, selectable band gaps as well as some unique electrical and optical properties. In addition, by alloying other isovalent components and then changing their compositions, these chalcopyrite compounds also offer the advantages of a controllable band gap and adjustable band edge positions for water oxidation/reduction reactions [11], [12] and [13]. Generally, the studies on I–III–VI2 chalcopyrite compounds for PEC systems were mainly focused on sulfides and selelides with the band gap energy of Eg ∼ 2.0 eV, like CuInS2 (1.53 eV) [6] and [7],CuGaSe2 (1.68 eV) [8] and [9], AgInS2 (1.87 eV) [10] and [11], and AgGaS2 (2.51 eV) [12] and [13]etc. However, tellurides with a suitable band gap like CuAlTe2 (2.06 eV) and AgAlTe2 (2.27 eV) [14] have rarely been reported as semiconductor photocathodes. Investigation on the electronic structures (like carrier effective masses, band edge positions etc.) of
tracheids tellurides can predict new photocathode candidates for water splitting. Furthermore, by studying the relationship on the band offset between these chalcopyrite compounds, one can find proper isovalent components to adjust the band gap as well as the band edge positions, which supplies an approach to optimize their electronic structures for water splitting.
