Northwestern researchers have devised a new formula for black hair dye using graphene. Leveraging graphene’s high surface area, flexibility, electrical and thermal conductivity, the inventors have developed a multi-functional hair dye that can be used to control the lightness/darkness of hair. The graphene dye is both robust (able to stay on even after 30 washes) and non-toxic (minimal to no hair damage was observed after wash-out). This technology has received considerable attention in the popular press, including the NY Times, BBC, NPR, Fast Company, Refinery29, and other news outlets.