A light valve containing ABX3 perovskite particles (200) suspended in a liquid suspension (300) that can control light transmittance is provided. The preferable ABX3 perovskite particles (200) are halide ABX3 perovskite particles wherein A is at least one of Cs+, CH3NH3+, and Rb+, B is at least one of Pb2+, Ge2+, and Sn2+, and X is at least one of Cl−, Br−, and I−. Use of the light valve in the manufacture of a light control device and a method of controlling light transmittance by using the light valve are also provided.