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Doping is a promising method of engineering the electronic structure of a metal oxide (thin film) to modify its optical and electrical properties. Using electrodeposition to elaborate Cu₂O thin films is a well-established preparation method. It has been reported that chlorine doping is an effective process to change the morphology and reduce the resistivity of Cu₂O thin films. Substitutional doping in Cu₂O n-type can go into either Cu site or O sites. Based on the valence of Cu, +1, and O, −2, in cuprous oxide, the potential dopants n-type include group VII elements for oxygen sites and group II elements for copper sites. Our work focuses on halogens such as chlorine as n-type dopants in Cu₂O. Out of all the halogens, F is best size-matched to O, but CuF is soluble in water. In this study, n-type doped Cu₂O are deposited by electrochemical method, by introducing substitutional n-type dopant Cl on FTO. From baths with different precursor chlorine (CuCl₂, NaCl and KCl), the change in the conductivity type from p type to n type was established and a systematic study was carried out to determine the influence of the nature of precursor onthe optical properties of Cu₂O. The effects of Cl precursor were investigated by X-ray diffraction (XRD), photoluminescence (PL), UV-Vis-IR spectrophotometry, atomic force microscopy (AFM) and photocurrent. The measurements of X-rays diffraction (XRD) confirm that the films are pure Cu₂O with polycrystalline structure and (111) phase which is strong out of plane texture for Cu₂O films. The photocurrent measurements shows that the conduction type changes from p-type to n-type. The optical measurements show a direct band gap depending on the Cl precursor. AFM images reveal that the choice of the precursor doping has a very significant influence on the surface morphology and size of the crystallites of thin Cu₂O