Solar-blind ultraviolet schottky barrier photodetectors based on colloidal ZnS quantum-dots were fabricated by solution processing. The cubic ZnS quantum-dots have an average particle size of 2.2 nm, and the bandgap was found to be 4.53 eV (~3.68 eV for bulk cubic ZnS). The photodetector showed an effective photoresponse for the solar-blind ultraviolet (UV) radiation. An on/off ratio of 9.2, responsivity of 1.60 mA/W and detectivity of 5.51×109 cm Hz1/2 W-1 were obtained under 254 nm radiation of 0.1 mWcm2, when operated at a bias voltage of 15 V. The response time of this device was of the order of 1 second, limited by the high resistance of the device. The results indicate that the photodetector using 2 nm ZnS quantum-dots is a promising candidate for solar-blind UV sensing.