Different types of QD as well as tuning them to absorb different light frequencies can be mixed together depending on whats best for the local climate. The desert might get more sunlight absorbing QD and Santa would get more IR absorbing because IR is 42 percent of light falling on earth, and gets through even in fog or night. That is an advantage of regional solar cell production. Also could be fillers like buckyballs or CNT that could aid electron transport. There are many advances reported everyday, hard to keep up. As far as I know Dr. Jabbour is still involved so we are in great shape. None better.