Abstract
Fluorescent carbon dots (CDs) are of interest as a promising alternative to quantum dots, partly because they do not include heavy metals. However, most CDs exhibit blue or green emission, while red-emitting CDs are required for a variety of applications. In the present work, CDs were synthesized by refluxing three phenylenediamine (PD) isomers with amino groups at different positions (o-PD, m-PD, and p-PD) in diphenyl ether at 250 °C for 4 h. Upon dispersing the resulting CDs in eight solvents with different polarities, emission colors ranging from green to red were observed. Among these CDs, p-PD-derived CDs exhibited both the longest emission wavelength range, from 538 to 635 nm, and the highest absolute red photoluminescence quantum yield (PLQY) of 15%. Herein the results are discussed based on a comparison of the polymerization processes of o-PD, m-PD, and p-PD. This work demonstrated that the optimum reaction time was 2 h, which yields a p-PD-derived CD dispersion in methanol with red emission and an absolute PLQY as high as 18%. Additionally, the use of 1-decanol and deuterated methanol in place of methanol improved the maximum absolute PLQY to 25% and 36%, respectively. These improved values are attributed to reduced concentration quenching by suppression of Ï€-πstacking interactions and inhibition of the nonradiative relaxation process through the vibration of OH groups, respectively.
| Original language | English |
|---|---|
| Journal | Langmuir |
| DOIs | |
| Publication status | Published - 2019 Jan 1 |
Fingerprint
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Surfaces and Interfaces
- Spectroscopy
- Electrochemistry
Cite this
Fluorescence Solvatochromism of Carbon Dot Dispersions Prepared from Phenylenediamine and Optimization of Red Emission. / Sato, Rina; Iso, Yoshiki; Isobe, Tetsuhiko.
In: Langmuir, 01.01.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Fluorescence Solvatochromism of Carbon Dot Dispersions Prepared from Phenylenediamine and Optimization of Red Emission
AU - Sato, Rina
AU - Iso, Yoshiki
AU - Isobe, Tetsuhiko
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Fluorescent carbon dots (CDs) are of interest as a promising alternative to quantum dots, partly because they do not include heavy metals. However, most CDs exhibit blue or green emission, while red-emitting CDs are required for a variety of applications. In the present work, CDs were synthesized by refluxing three phenylenediamine (PD) isomers with amino groups at different positions (o-PD, m-PD, and p-PD) in diphenyl ether at 250 °C for 4 h. Upon dispersing the resulting CDs in eight solvents with different polarities, emission colors ranging from green to red were observed. Among these CDs, p-PD-derived CDs exhibited both the longest emission wavelength range, from 538 to 635 nm, and the highest absolute red photoluminescence quantum yield (PLQY) of 15%. Herein the results are discussed based on a comparison of the polymerization processes of o-PD, m-PD, and p-PD. This work demonstrated that the optimum reaction time was 2 h, which yields a p-PD-derived CD dispersion in methanol with red emission and an absolute PLQY as high as 18%. Additionally, the use of 1-decanol and deuterated methanol in place of methanol improved the maximum absolute PLQY to 25% and 36%, respectively. These improved values are attributed to reduced concentration quenching by suppression of Ï€-πstacking interactions and inhibition of the nonradiative relaxation process through the vibration of OH groups, respectively.
AB - Fluorescent carbon dots (CDs) are of interest as a promising alternative to quantum dots, partly because they do not include heavy metals. However, most CDs exhibit blue or green emission, while red-emitting CDs are required for a variety of applications. In the present work, CDs were synthesized by refluxing three phenylenediamine (PD) isomers with amino groups at different positions (o-PD, m-PD, and p-PD) in diphenyl ether at 250 °C for 4 h. Upon dispersing the resulting CDs in eight solvents with different polarities, emission colors ranging from green to red were observed. Among these CDs, p-PD-derived CDs exhibited both the longest emission wavelength range, from 538 to 635 nm, and the highest absolute red photoluminescence quantum yield (PLQY) of 15%. Herein the results are discussed based on a comparison of the polymerization processes of o-PD, m-PD, and p-PD. This work demonstrated that the optimum reaction time was 2 h, which yields a p-PD-derived CD dispersion in methanol with red emission and an absolute PLQY as high as 18%. Additionally, the use of 1-decanol and deuterated methanol in place of methanol improved the maximum absolute PLQY to 25% and 36%, respectively. These improved values are attributed to reduced concentration quenching by suppression of Ï€-πstacking interactions and inhibition of the nonradiative relaxation process through the vibration of OH groups, respectively.
UR - http://www.scopus.com/inward/record.url?scp=85075552600&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85075552600&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.9b02739
DO - 10.1021/acs.langmuir.9b02739
M3 - Article
C2 - 31702929
AN - SCOPUS:85075552600
JO - Langmuir
JF - Langmuir
SN - 0743-7463
ER -