title: Excitation wavelength independent visible color emission of carbon dots.
abstract: Carbon dots (CDs) usually emit a strong blue light and excitation wavelength dependent long wavelength lights. This significantly limits their applications because one has to use a series of different excitation light sources to get different colors and the long wavelength emissions are usually very weak. We found that one type of CDs synthesized from p-phenylenediamine could emit various long wavelength lights (green to red) independent of the excitation wavelength when dispersed in different solvents. The photoluminescence quantum yields of the same CDs were 10-35% in different solvents for different color emissions. Based on this solvent-color effect, we further mixed the same CDs with different polymers to form solid CD films for various color emissions, and these film emissions were also excitation wavelength independent. Multicolor LEDs were demonstrated with the same CDs in solution and solid film states for color displays.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China. wyu6000@gmail.com and Institute for Micromanufacturing, Department of Chemical Engineering, Louisiana Tech University, Ruston, LA 71270, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China. wyu6000@gmail.com.
authors.forename: Chun
authors.initials: C
authors.lastname: Sun
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China. wyu6000@gmail.com and Department of Chemistry and Physics, Louisiana State University, Shreveport, LA 71115, USA.
authors.forename: Xingru
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China. wyu6000@gmail.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Brown University, Providence, RI 02912, USA.
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Colvin
authors.affiliation: Advanced Center for Laser Science and Spectroscopy, Department of Physics, Hampton University, Hampton, VA 23668, USA.
authors.forename: Quinton
authors.initials: Q
authors.lastname: Rice
authors.affiliation: Advanced Center for Laser Science and Spectroscopy, Department of Physics, Hampton University, Hampton, VA 23668, USA.
authors.forename: Jaetae
authors.initials: J
authors.lastname: Seo
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
authors.forename: Shengyu
authors.identifier: http://orcid.org/0000-0002-3056-2296
authors.initials: S
authors.lastname: Feng
authors.affiliation: Institute for Micromanufacturing, Department of Chemical Engineering, Louisiana Tech University, Ruston, LA 71270, USA.
authors.forename: Shengnian
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China. wyu6000@gmail.com and Department of Chemistry and Physics, Louisiana State University, Shreveport, LA 71115, USA.
authors.forename: William W
authors.identifier: http://orcid.org/0000-0001-5354-6718
authors.initials: WW
authors.lastname: Yu