A white light emitting device (backlight) comprises: a Multiple Quantum Well (MQW) dual-wavelength LED; and a narrowband photoluminescence material that generates red light with a peak emission wavelength from about 620 nm to about 660 nm. The MQW dual-wavelength LED comprises at least one first Quantum Well (QW) that generates blue light with a dominant wavelength from 440 nm to 470 nm and at least one second Quantum Well (QW) to generate green light with a dominant wavelength from 520 nm to 540 nm.