The authors demonstrate the implementation of a white-light device by spin-coating CdSe/ZnS nanocrystals (NCs) on the top of a blue/green two-color InGaN/GaN quantum-well light-emitting diode for converting blue and green emissions into red light through the absorption/reemission process. Meanwhile, Au nanoparticles are mixed with CdSe/ZnS NCs for generating localized surface plasmon (LSP) modes to couple with the CdSe/ZnS NCs. The LSP modes can absorb green emission and effectively transfer the energy into the CdSe/ZnS NCs through the coupling process for enhancing red emission. With the LSP coupling process, the conversion efficiency from the blue/green range into red light can be increased by around 30%. The conversion quantum efficiency can reach 52.8%.