Full-color technologies applied on organic light-emitting diode (OLED) devices have advanced significantly. Common full-color technologies include the applications of multi-layered structures, color conversion, juxtaposed pixels, color filters, etc. To apply the color conversion method, light emitted by certain organic materials is used as excitation to excite color-converting materials for illuminating light with different colors, e.g., red, green, and blue. In this way, full-color light can be produced. To apply the color conversion method, color-converting materials need to be disposed into the OLED device. Under the excitation of the light emitted by the organic light-emitting materials, the color-converting materials generate light that radiates in various directions. A portion of the light emitted by the color-converting materials may also radiate on the side of the organic light-emitting materials that is not designed to be the light-emitting side. As a result, intensity and color saturation of the light emitted at the light-emitting side of the OLED device may be reduced. The light emission efficiency of the OLED device can be reduced or impaired.