Hybrid organic-inorganic perovskites have emerged as promising materials for next-generation optoelectronic devices owing to their tunable properties and low-cost fabrication. We report the synthesis of 3D hybrid perovskites with monoethanolammonium cations. Specifically, we investigated the optoelectronic properties and morphological characteristics of polycrystalline films of hybrid perovskites MA xMEA 1-xPbI 3, which contain methylammonium (MA) and monoethanolammonium (MEA) cations. MA xMEA 1-xPbI 3 crystallizes in a tetragonal perovskite structure. The substitution of methylammonium cations with monoethanolammonium ions led to an increase in the lattice parameters and the bandgap energy. Energy level diagrams of the synthesized samples were also constructed. The bandgap of MA 0.5MEA 0.5PbI 3 makes it a promising material for use in tandem solar cells. These polycrystalline films, namely MA 0.5MEA 0.5PbI 3 and MA 0.25MEA 0.75PbI 3 were fabricated using a one-step spin-coating method without an antisolvent. These films exhibit a uniform surface morphology under the specified deposition parameters. Within the scope of this study, no evidence of dendritic structures or pinhole-type defects were observed. All synthesized samples demonstrated photocurrent generation under visible light illumination. Moreover, using monoethanolammonium cations reduced the hysteresis of the I-V characteristics, indicating improved device stability.