<p>The nanoscale spinel structure of n-type lead aluminate (PAS) provides synergistic effects from its composite components, resulting in a tunable band gap for carrier excitation and charge transport upon interaction with black-light irradiation. In the present paper, the PAS was prepared using a Co-precipitation synthesis method. The organized specimen was primarily characterized using different efficient analysis methods. Then, for the first time, an ultraviolet light photodetector based on PAS (UPA) has been developed to detect and annotate various power densities of 365nm-UV light (P_Ds). I-V characteristics of the UPA showed that the net current is affected by the changes in temperature, bias voltage, and UV light P_D. The UPA offered low-dark current, acceptable ideality factor, and a modified Richardson constant of 48.47 A.cm⁻².K⁻². Furthermore, it exhibited nonlinear asymmetric rectification behavior, high contrast ratio near zero volts, and meaningful short-circuit current at 0 V, indicating its self-powered nature. The study of the I_Ph-t characteristics of the device revealed repetitive stability, acceptable R_Ph (2.182 A/W), good D^* (4.06 × 10¹¹ Jones), high EQE (740.68%), NG (24.24 W⁻¹), and LDR of 54.54 dB at the P_D of 2.2 mW/cm². In addition, the UPA exposed a t_R of 4 s, I_MPh of 17 µA, and NEP of 24.39 W.Hz^−0.5 at P_D of 79.6 mW/cm². The stability of the R_Ph and D^* over three months indicates that the dark current in the UPA is controlled and minimized. In conclusion, the possible mechanism in the device operation was debated in detail by employing a standard thermionic emission–diffusion model and energy band diagrams.</p>