A fabrication technique using Al₂O₃-passivated local contacts was employed to produce narrow-bandgap CuInSe₂ (CISe) photoabsorbers, which are well-suited as bottom cell materials in tandem devices. However, the performances of CISe cells with narrow bandgaps are impeded by the recombination of charge carriers, which reduces the open-circuit voltage (V_OC). To overcome this limitation, an additional Al₂O₃ passivation layer was added to CISe solar cells. This enhanced the V_OC while maintaining a spectral response of up to 1.0 eV, thereby boosting the photovoltaic conversion efficiency of the devices. Further, the Al₂O₃ passivation layer within the CISe absorber effectively mitigated the recombination of charge carriers, resulting in a substantial improvement in efficiency. Specifically, the Al₂O₃-passivated local contact hindered the charge-carrier recombination at the rear contact, leading to a marked increase in the V_OC. Consequently, the overall photovoltaic conversion efficiency increased significantly from 10.4 % to 13 %. These results are expected to greatly further the development of CISe solar cells and achieve remarkable photovoltaic conversion efficiencies.