Preparation and characterization of optically transparent and photoluminescent electrospun nanofiber composed of carbon quantum dots and polyacrylonitrile blend with polyacrylic acid

Novel photoluminescence (PL) composite nanofibers (NFs) consist of carbon qunatum dots (CQDs) and polyacrylonitrile blend with polyacrylic acid (PAN/PAA) were fabricated by the coelectrospinning process. The air-dried CQDs containing NFs were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, spectrofluorometer, and confocal microscopy. CQDs are familiar to emit blue, green and red color depending on the excitation energy. The PAN/PAA/CQDs NFs were found to be optically transparent and exhibited PL properties similar to CQDs. Therefore, blue, green and red color was observed under confocal microscope from the NFs membrane while the sample was excited by 405 nm, 488 nm and 543 nm lasers. The results indicated the well preserved quantum confinement properties of the CQDs inside the polymer matrix without aggregation or substantial quantum dots growth.