High-performance and high-stability photodiodes are introduced by using α-CsPbI₃ perovskite nanocrystals (NCs) phase-stabilized with a low-temperature solution-treated active layer. In addition to the high charge mobility, the high absorption coefficient, and IR-blind characteristics of the perovskite material, the defect-tolerant nature of α-CsPbI₃ perovskite NCs are combined to realize hysteresis-free and high detectivity photodiodes. To further minimize defects state of interface, originating from multi-layer photodiode construction, a poly(3-hexylthiophene) layer is strategically introduced as a passivation layer, resulting in a low diode ideality and a noise equivalent power. As a result, high detectivity is introduced with hysteresis-free devices. Furthermore, the optimized photodiode exhibits excellent stability under high humidity conditions owing to the intrinsic nature of the defect-tolerant α-CsPbI3 perovskite NCs.