X-ray photoelectron and absorption spectroscopy of mixed lanthanum copper oxychalcogenides LaCuOSe1−xTex (0 ≤ x ≤ 1)

► Shifts in O 1s BEs are influenced by competing effects in charges of neighbouring La and more distant Ch atoms, according to charge potential model. ► Changes in Cu K- and Se K-edge spectra are related to Cu-to-Ch charge transfer within [CuCh] layers. ► Previously believed to be insignificant, La-Ch interactions between [LaO] and [CuCh] layers are confirmed.