A photocatalytic device includes one transparent or translucent carrier and at least one photocatalytic film. The carrier is in the form of a sheet with two opposite surface. At least one of the two surfaces of the carrier is at least partially coated with the photocatalytic film. The photocatalytic film is photocatalytic activated by visible light with wavelength>；400 nm for providing the antibacterial functionality. In some situation, only the outer surface of the carrier is coated with the photocatalytic film. In other situation, only the inner surface of the carrier is coated with the photocatalytic film. There are situations where both surfaces of the carrier are coated with the photocatalytic film. The carrier has an attaching mechanism for attaching the carrier to the external solid object, and the carrier is attachable to and detachable from the external solid object hands of a user without using a tool.
