Utilizing density functional theory (DFT), a comparative study has been performed on monolayer ZnO (M-ZnO) doped with rare earth elements (RE=Ce, Dy and Eu) for potential application as a photoanode of a dye sensitized solar cell (DSSC). The implementation of the Quantum Espresso code facilitated the optimization of the structural configuration, allowing for the computation of a diverse array of properties, including the structural, electronic, optical, and electrical conductivity. Analysis on the formation energies indicated that RE (Ce, Dy and Eu) doped M-ZnO maintains a stable energetic configuration with Dy doping yielding the most stable compound of M-ZnO. In GGA +U formalism, an investigation into the electronic structure revealed a direct band gap energy values of 3.38, 3.19, 3.14 and 3.24 eV for undoped, Ce, Dy and Eu doped M-ZnO respectively. The Fermi level transitioned to the conduction band, signifying n-type properties. Furthermore, these compounds exhibited exceptional optical characteristics, notably a significant absorption coefficient that varied between 105 cm−1 and 106 cm−1. The BoltzTrap code was employed to calculate electrical conductivity. Results demonstrate that the conductivity is significantly enhanced following the doping process. Accordingly, it is justifiable to state that RE (Ce, Dy and Eu) doped M-ZnO possess significant potential for application in DSSC technology.