A system for coating a substrate surface with a diffuser coating includes an ultrasonic vibrating device, a supply device and a low pressure air source. The supply device supplies a liquid coating material or precursor solution to the ultrasonic vibrating device. The ultrasonic vibrating device is operable to vibrate to atomize the coating material and to discharge airborne particles at a discharge end of the ultrasonic vibrating device. The low pressure air source generates low pressure air flow generally proximate to the discharge end to guide at least some of the airborne particles onto the substrate surface. The ultrasonic vibrating device may be at a coating chamber and the substrate may be positionable within the coating chamber. A conveyor may be operable to convey substrates through the coating chamber, whereby the coating particles are guided onto the substrate surface as the substrate moves through the coating chamber.