[Molybdenum disulfide] has a crucial characteristic, known as a bandgap, that allows it to be made into solar cells or integrated circuits. But unlike silicon, now used in most solar cells, placing the film under strain in the “solar energy funnel” configuration causes its bandgap to vary across the surface, so that different parts of it respond to different colors of light.
Trivia: Molybdenum disulfide also is used as a vacuum lubricant/anti-seizing agent (its use is critical if you have metal-on-metal contact if the metals are the same); it’s similar in effect to graphite, but has a vary low vapor pressure. There’s also the fun of it being very messy — it’ll be all over you in a flash, like a toddler playing in mud.