Solvothermal preparation of nitrogen and phosphorus-doped carbon dots with PET waste as precursor and its application

PET-based nitrogen and phosphorus-doped Carbon Dots (NP-CDs) was prepared by solvothermal method with PET waste as raw materials. In terms of structure, NP-CDs were spherical structures with an average particle size of 2.8 nm, and its surface contains amino groups. The as-prepared NP-CDs exhibit excitation-independent emission properties from 300 nm to 430 nm, and the optimal excitation and emission wavelength was 340 nm and 460 nm. In terms of application, the as-prepared NP-CDs could be used to a pH sensor in the range of 2.3–12.3. When NP-CDs were dispersed in polyvinyl alcohol (PVA) matrix, excellent light blocking films(LBFs) for UV and blue light were obtained. When the ratio of NP-CDs is 14 %, it still does not affect the line of sight, and the barrier rate to UV(380 nm) and blue(430 nm) light is as high as 90% and 80 %. In addition, the WLED device with a colour coordinate of (0.29,0.32) and a colour temperature of 8022 K can be obtained with the combination of NP-CDs dispersed in PVA matrix and 395 nm LED chips.