Mixed-halide perovskites, CH3NH3PbI3−xClx, enabled fabrication of highly efficient perovskite solar cells (PeSCs). Chloride ions make the morphology, carrier diffusion length, and stability of perovskite films better. However, the reported device performances of mixed-halide PeSCs have showed non-significant difference of efficiencies with those of the triiodide perovskite, CH3NH3PbI3, devices. This makes uncertainty for the benefits from the presence of Cl ions in the mixed-halide perovskite films. To be clear an effect of Cl- inclusions on optoelectronic properties of perovskite devices, suitable device structure and spectroscopic analysis should be introduced. In this work, we fabricated lateral-structured perovskite device to study electrical properties of perovskite devices, which showed a clear contrast of photoelectric property between mixed-halide and triiodide perovskites and furthermore provided a suitable device for spectroscopic measurements on actual device architecture.