Organic-inorganic hybrid perovskites ( have drawn explosive attention in the research communities of photovoltaics due to their outstanding intrinsic optoelectronic and electronic properties excellent band tunability, effective charge collection, long exciton diffusion length and high absorption coefficient In addition, recent advancements have verified that these materials have a great potential in the field of light-signal detection.
Based on the characteristics that the spectral shape is tunable in accordance with the device thickness due to the optical interference effect, the thickness of the active layer was controlled to achieve various spectral response of the perovskite photodiodes( PePDs in many studies However, when the thickness of active layer increases, the defect density of the device which causes degradation of device performance also increases To solve this problem, we controlled the spectral response characteristics of the PePDs by changing the thickness of the charge transportlayer(CTL) instead of the active layer By controlling the CTL thickness, we could successfully fabricate PePDs showing relatively high external quantum efficiency(EQE) at a specific wavelength region, such as absorption tail region,  without apparent increase of dark current density