Solar-blind ultraviolet photodetector holds significant application potential in fields such as military defense, communication, medical treatment, and environmental monitoring. Developing self-powered detectors is essential for eliminating the dependence on external bias voltage and reducing high energy consumption of traditional devices. In this study, high-quality β-Ga₂O₃ thin films were prepared via plasma-enhanced chemical vapor deposition and which were subsequently combined with spin-coated PEDOT:PSS to fabricate an organic–inorganic van der Waals heterojunction self-powered solar-blind photodetector. Its photoelectric performance and potential for single-pixel imaging applications were systematically investigated. Structural characterization reveals that the prepared β-Ga₂O₃ thin film exhibits good crystallinity and a smooth surface, with selective absorption in the solar-blind ultraviolet region and an optical bandgap of approximately 4.92 eV. Under zero bias and 254 nm illumination at intensity of 47 μW/cm², the detector achieves a photo-to-dark current ratio of 8.8×10³, a responsivity of 0.106 A/W, and an external quantum efficiency of 38%. The photocurrent exhibits a near-linear dependence on light intensity. The device operates stably under both positive and negative bias, with low dark current, minimal noise, and excellent weak-light detection capability. By employing a fixed-step point-by-point scanning method, the detector achieved single-pixel solar-blind ultraviolet optical imaging of the letters “IMU”, demonstrating good imaging quality and high fidelity. The heterojunction detector developed in this study combines the advantages of self-powered operation, simple structure, and low cost, overcoming the limitations of traditional materials used in single-pixel imaging approaches, thereby offering a promising strategy for improving solar-blind ultraviolet detection technology and demonstrating significant potential for practical applications in the field of single-pixel optical imaging.