Engineering white light-emitting diodes with high color rendering index from biomass carbonized polymer dots.

Carbonized polymer dots (CPDs) have promise in the fields of sensing, bioimaging, and optoelectronic devices due to their excellent optical properties, favorable biocompatibility, and superior stability. Biomass CPDs present greater advantages in terms of their lack of toxicity, low cost, easy preparation, and feasibility in terms of luminescence-related applications. Here, two kinds of fluorescent CPDs were obtained through the simple hydrothermal method using biomass avocado peel (CPDs-P) and sarcocarp (CPDs-S) as carbon sources. Interestingly, these two biomass CPDs have excellent applications in ion detection and light-emitting diodes (LEDs). Analysis and results show that CPDs-P possess better sensitivity to Fe because they have more oxygen-containing functional groups. After mixing with epoxy resin, warm and cold white LEDs with CIE (Commission Internationale de L 'Eclairage) coordinates (0.38, 0.39) and (0.29, 0.34) were constructed successfully from extremely stable CPDs-P and CPDs-S. The high color rendering index of the prepared white LEDs are 90.47 and 84.54. This study shows that these biomass CPDs are promising materials in sensing and white LEDs illumination.