An electronic device may have a display with an array of pixels. Each pixel may include inorganic light-emitting diodes of the same color such as a blue inorganic light-emitting diode. To emit different colors of light using the same type of inorganic light-emitting diodes, quantum dot layers may be used. Each quantum dot layer may have an associated reflective layer. Each light-emitting diode may also have an associated reflective layer. The reflective layer for the light-emitting diode may conform to the light-emitting diode or may be separated from the light-emitting diode by gap. When the reflective layer is separated from the light-emitting by a gap, the gap may be filled by a quantum dot layer or a diffusive layer.