The alternating current electroluminescent (ACEL) device is ideally suited for flat light emitting owing to its particular properties, compactness, robustness, and flexibility. In this article, six types of white electroluminescent devices containing red fluorescent dyes as light-conversion materials in different position were fabricated by spin coating, controlling the thickness of layers accurately. The luminance, efficiency, light emission spectra and CIE coordinates of devices were investigated. The results show that the performance of the devices significantly depends on the position of the light-conversion layers, and the hybrid structure has excellent performance with the highest luminance. From the findings of this study, a practical and promising method is derived to optimize both the efficiency and luminance of conventional devices, and it makes sense for the latest color convertors such as quantum dots and perovskites in LEDs.