Influence of Doping and Temperature on Solvatochromic Shifts in Optical Spectra of Carbon Dots

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989592%3A15310%2F16%3A33159997" target="_blank" >RIV/61989592:15310/16:33159997 - isvavai.cz</a>

Výsledek na webu

<a href="http://pubs.acs.org/doi/pdf/10.1021/acs.jpcc.5b12294" target="_blank" >http://pubs.acs.org/doi/pdf/10.1021/acs.jpcc.5b12294</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpcc.5b12294" target="_blank" >10.1021/acs.jpcc.5b12294</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Influence of Doping and Temperature on Solvatochromic Shifts in Optical Spectra of Carbon Dots

Popis výsledku v původním jazyce

Solvatochromic shifts in nitrogen-doped and nitrogen-sulfur-co-doped carbon dots are studied by analyzing absorption, photoluminescence excitation and photoluminescence emission spectra, and their emission lifetimes in two different solvents, protic water (H2O) and aprotic dimethyl sulfoxide (DMSO). We identify three emission bands belonging to the sp(2)-hybridized core, the edge, and the functional surface groups of carbon dots, as well as surface attached fluorophores that emit within the edge band energy range. Edge and surface bands show opposite solvatochromic shifts solely depending on the doping heteroatoms. We are able to reproduce emission shifts observed in DMSO by heating CDs in H2O from 7 to 87 degrees C, when the polarity and hydrogen-bonding strength of the solvent are reduced. Intrinsic edge band transitions are found to be strongly influenced by the solvent polarity, as charge transfer processes dominate. Surface band transitions are found to be influenced especially by hydrogen bonding between the carbon dots and the solvent. Together, these processes lead to characteristic, solvatochromic blue and red shifts of the emission bands. Furthermore, we observe strong emission quenching in the edge band but emission enhancement in the surface band of carbon dots in DMSO. This is attributed to quenched organic fluorophores that are formed during the carbon dot synthesis, leaving only intrinsic edge band emission while the radiative decay in the surface band is enhanced. As a result, the edge band of nitrogen-sulfur-co-doped carbon dots switches from an excitation-independent, fluorophore-like emission to an excitation-dependent emission associated with intrinsic edge states.

Název v anglickém jazyce

Influence of Doping and Temperature on Solvatochromic Shifts in Optical Spectra of Carbon Dots

Popis výsledku anglicky

Solvatochromic shifts in nitrogen-doped and nitrogen-sulfur-co-doped carbon dots are studied by analyzing absorption, photoluminescence excitation and photoluminescence emission spectra, and their emission lifetimes in two different solvents, protic water (H2O) and aprotic dimethyl sulfoxide (DMSO). We identify three emission bands belonging to the sp(2)-hybridized core, the edge, and the functional surface groups of carbon dots, as well as surface attached fluorophores that emit within the edge band energy range. Edge and surface bands show opposite solvatochromic shifts solely depending on the doping heteroatoms. We are able to reproduce emission shifts observed in DMSO by heating CDs in H2O from 7 to 87 degrees C, when the polarity and hydrogen-bonding strength of the solvent are reduced. Intrinsic edge band transitions are found to be strongly influenced by the solvent polarity, as charge transfer processes dominate. Surface band transitions are found to be influenced especially by hydrogen bonding between the carbon dots and the solvent. Together, these processes lead to characteristic, solvatochromic blue and red shifts of the emission bands. Furthermore, we observe strong emission quenching in the edge band but emission enhancement in the surface band of carbon dots in DMSO. This is attributed to quenched organic fluorophores that are formed during the carbon dot synthesis, leaving only intrinsic edge band emission while the radiative decay in the surface band is enhanced. As a result, the edge band of nitrogen-sulfur-co-doped carbon dots switches from an excitation-independent, fluorophore-like emission to an excitation-dependent emission associated with intrinsic edge states.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CF - Fyzikální chemie a teoretická chemie

OECD FORD obor

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Projekt

<a href="/cs/project/LO1305" target="_blank" >LO1305: Rozvoj centra pokročilých technologií a materiálů</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Physical Chemistry Part C: Nanomaterials and Interfaces

ISSN

1932-7447

e-ISSN

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Svazek periodika

120

Číslo periodika v rámci svazku

19

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

14

Strana od-do

10591-10604

Kód UT WoS článku

000376417500052

EID výsledku v databázi Scopus

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