Improving the efficiency of the phosphor improves the efficiency of the LED

Film thickness versus number of coats for screen printed Cabot phosphor layers. Note the uniformity of the films in the SEM images.
The overarching goal of this project was to develop luminescent materials using aerosol processes for making improved LED devices for solid state lighting. In essence this means improving white light emitting phosphor-based LEDs by improvement of the phosphor and phosphor layer. The efficiency of these LEDs is based on the combined efficiency of the LED, phosphor, and the interaction between the two.

The structure of these types of light sources is a blue or UV LED under a phosphor layer that converts the blue or UV light to a broad visible (white) light. Traditionally, this is done with a blue emitting diode combined with a blue absorbing, broadly yellow emitting phosphor such as Y3Al5O12:Ce (YAG). A similar result may be achieved by combining a UV emitting diode and at least three different UV absorbing phosphors: red, green, and blue emitting. These emitted colors mix to make white light.

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