Electrodeposited Cu2O doped with Cl: Electrical and optical properties

Abstract

For understanding the electrical and optical properties of electrodeposited Cl-doped Cu 2 O thin films, we have studied layers with increasing thickness and Cl concentrations of 0.8 and 1.2 at. %. The deposits were characterized by measuring the charge transport, the optical reflectance, and the photoluminescence. No significant decrease of electrical resistivity was observed in doped samples compared to undoped ones. A decrease of about five orders of magnitude was measured and ascribed to the presence of pinholes, as confirmed by scanning electron microscopy analyses. From optical measurements, we concluded that the Cl atoms are incorporated into substitutional sites of Cu 2 O lattices in agreement with photoluminescence results showing a strong reduction in the peak intensity of V O þ2 defects in comparison to undoped layers. Computational calculation using density functional theory has pointed out high formation energy for single Cl related defects, but low formation energy for Cl-defect complexes, such as Cl O þ V Cu , that strongly compensate the carriers generated by the Cl doping.

Understanding the role of Cl doping in the oxygen evolution reaction on cuprous oxide by DFT

“…When Cu 2 O is doped with Cl, the Cu vacancy formation energy is lowered by 0.20 eV and it is more facile to have Cu vacancies with Cl doping, which is consistent with previous studies. 36,57 Thus V Cu –Cl–Cu 2 O(111) should be the most possible catalyst for OER catalyzed Cl-doped Cu 2 O. Therefore, Cl plays dual roles: one is to increase the adsorption ability of Cu 2 O by introducing excess electrons, which improves the OER activity of Cu 2 O; the other is to promote the formation of a Cu vacancy.…”

“…36 Then, Cu CUS was removed to form vacancies from Cl-Cu 2 O(111) to simulate V Cu -Cl-Cu 2 O(111) because Cu CUS vacancies were more favored than Cu CSA on Cl-Cu 2 O(111). 35,36 For all the calculations, the top two layers of the slab were allowed to relax until the force on the atoms was converged to 0.02 Ev Å À1 , while the remaining bottom three layers were fixed.…”

“…32,33 For example, the defects of electrocatalysts have a significant impact on the OER performance. 34 Because the coordinatively unsaturated copper vacancies (V Cu ) are expected to form in the Cu 2 O surface and Cl-doped Cu 2 O surface, 35,36 we also consider the effect of surface defects before and after Cl doping. Four kinds of Cu…”

“…32,33 For example, the defects of electrocatalysts have a significant impact on the OER performance. 34 Because the coordinatively unsaturated copper vacancies (V Cu ) are expected to form in the Cu 2 O surface and Cl-doped Cu 2 O surface, 35,36 we also consider the effect of surface defects before and after Cl doping. Four kinds of Cu 2 O surface models are established to be compared, including the pristine Cu 2 O(111), Cu 2 O(111) with V Cu (V Cu –Cu 2 O(111)), Cl-doped Cu 2 O(111) (Cl–Cu 2 O(111)) and Cl–Cu 2 O(111) with V Cu (V Cu –Cl–Cu 2 O(111)).…”

Defects controlling electrical and optical properties of electrodeposited Bi doped Cu2O

“…Indeed, such information given by E d has already been used in other works. 17,52,53 In order to obtain an estimate for E d , it is helpful to make use of the following empirical relationship, which was proposed by WD for crystals containing a single anion species 51…”