Carbon dots derived from non-biomass waste for a sensing application

Research on sensor materials has expanded with the advancement of sensing technologies across industries. Carbon dots (CDs) derived from organic waste and biomass have attracted widespread interest in sensing applications with their prominent properties (e.g., photoluminescence and biocompatibility). The use of non-biomass waste (NBW) as a raw material thus becomes important to make their production process sustainable without additional treatments to cause environmental pollution. Due to scarcity of research on NBW-based CDs, this review explores the synthesis methods, properties, and sensing applications of NBW-based CDs. The potential of NBW-based CD sensors for metal ions (e.g., Fe³⁺ and Cu²⁺) and humidity has been evaluated in various respects. In the case of Fe³⁺ and Cu²⁺, CDs derived from waste medical gloves and polyolefin pyrolysis residue exhibit the lowest limit of detection values of 0.29 nM and 6 nM, respectively, among all sensors examined on parallel basis. In the case of humidity, graphite-based CDs exhibit the best performance, with a minimum response time of 15 s. This review overall highlights the challenges and opportunities for the expanded application of NBW-based CDs toward the construction of efficient sensing systems based on performance evaluations.