Surface Functional Groups Effect on the Absorption Spectrum of Carbon Dots: Initial TD-DFT Study
Reza Umami(a) Fitri Aulia Permatasari(a) Citra Deliana Dewi Sundari(b,c) Fahdzi Muttaqien (d,e) and Ferry Iskandar(a,e,*)

(a) Department of Physics, Faculty Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, West Java 40132, Indonesia.
(b)Inorganic and Physical Chemistry Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, West Java 40132, Indonesia.
(c)Department of Chemistry Education, UIN Sunan Gunung Djati Bandung, Jl. Cimincrang, Bandung, West Java 40292, Indonesia.
(d)Master Program in Computational Science, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
(e)Research Center for Nanoscience and Nanotechnology, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, West Java 40132, Indonesia.

Abstract

Carbon dots (CDs) has attracted considerable interest due to its remarkable performance, low cost and ease of preparation, and wide range of potential applications. The surface engineering, including modifying the surface functional group and subsequent chemical modification are preferable to achieve the requirement of the specific application. Oxygen and Nitrogen-based surface functional groups are two common functionalization on CDs that subsequently generated during the synthetic process. In this study, we elucidate the optical properties of Oxygen- and Nitrogen-functionalized CDs by means of time dependent density functional theory (TD-DFT). Both considered functional groups, the carbon-oxygen double bond (-C=O) and amino groups (-NH2), are quite favourable to tailor the optical properties of CDs, especially in enhancing its absorption spectrum. Moreover, the carbonyl (-C=O) and amino (-NH2) functional groups effectively serve a new absorption peak in the first near infra-red window (650-900 nm). Our results may suggest potential application of the amino and carbonyl functionalized CDs as a photothermal agent in the photothermal cancer therapy.

Keywords: absorption- Carbon dots- functional groups- TD-DFT-

Topic: Materials Physics