Graphitic carbon nitride (CN) materials have drawn remarkable research attention due to their extraordinary optical properties, which are especially promising for metal-free photocatalysis and photoluminescence. Herein we theoretically study the light absorption, electronic, and excitonic characteristics of covalently hybrid structures of CN quantum dots (CNQDs) and graphene quantum dots (GQDs). Density functional theory (DFT) and time-dependent DFT (TD-DFT) reveal that the relative size of CNQDs and GQDs and chemical modification to GQDs or CNQDs surface are critical determining the absorption and photocatalytic/photoluminescent performances of the as-studied structures. Importantly, the distribution position of the photoexcited electron–hole pair is found to depend on the relative size of CNQDs and GQDs, and chemical groups such as epoxy group may lead to distinct exciton distributions in the CNQD–GQD hybrid structures after attaching them to GQD or CNQD surface as compared to the case of pristine GQD and CNQD, indicating a non-negligible influence of unintended chemical reactions to CNQDs and/or GQDs under working conditions on the efficiencies of the materials for photocatalytic and photoluminescent applications.
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Ong W-J, Tan L-L, Ng YH, Yong S-T, Chai S-P (2016) Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: Are we a step closer to achieving sustainability? Chem Rev 116:7159–7329
Kessler FK, Zheng Y, Schwarz D, Merschjann C, Schnick W, Wang X, Bojdys MJ (2017) Functional carbon nitride materials-design strategies for electrochemical devices. Nat Rev Mater 2:17030
Liu J, Liu Y, Liu N, Han Y, Zhang X, Huang H, Lifshitz Y, Lee S-T, Zhong J, Kang Z (2015) Metal-free efficient photocatalyst for stable visible water splitting via a two-electron pathway. Science 347:970–974
Xu J, Shalom M, Piersimoni F, Antonietti M, Neher D, Brenner TJK (2015) Color-tunable photoluminescence and NIR electroluminescence in carbon nitride thin films and light-emitting diodes. Adv Opt Mater 3:913–917
Chu S, Wang C, Feng J, Wang Y, Zou Z (2014) Melem: a metal-free unit for photocatalytic hydrogen evolution. Int J Hydrog Energy 39:13519–13526
Zhang X, Xie X, Wang H, Zhang J, Pan B, Xie Y (2013) Enhanced photoresponsive ultrathin graphitic-phase C3N4 nanosheets for bioimaging. J Am Chem Soc 135:18–21
Cui Q, Xu J, Wang X, Li L, Antonietti M, Shalom M (2016) Phenyl-modified carbon nitride quantum dots with distinct photoluminescence behavior. Angew Chem Int Ed 55:3672–3676
Bian J, Li Q, Huang C, Li J, Guo Y, Zaw M, Zhang R-Q (2015) Thermal vapor condensation of uniform graphitic carbon nitride films with remarkable photocurrent density for photoelectrochemical applications. Nano Energy 15:353–361
Liu J, Xu H, Xu Y, Song Y, Lian J, Zhao Y, Wang L, Huang L, Ji H, Li H (2017) Graphene quantum dots modified mesoporous graphite carbon nitride with significant enhancement of photocatalytic activity. Appl Catal B 207:429–437
Che W, Cheng W, Yao T, Tang F, Liu W, Su H, Huang Y, Liu Q, Liu J, Hu F, Pan Z, Sun Z, Wei S (2017) Fast photoelectron transfer in (cring)-C3N4 plane heterostructural nanosheets for overall water splitting. J Am Chem Soc 139:3021–3026
Song Z, Li Z, Lin L, Zhang Y, Lin T, Chen L, Cai Z, Lin S, Guo L, Fu F, Wang X (2017) Phenyl-doped graphitic carbon nitride: photoluminescence mechanism and latent fingerprint imaging. Nanoscale 9:17737–17742
Wang Y, Liu X, Liu J, Han B, Hu X, Yang F, Xu Z, Li Y, Jia S, Li Z, Zhao Y (2018) Carbon quantum dot implanted graphite carbon nitride nanotubes: excellent charge separation and enhanced photocatalytic hydrogen evolution. Angew Chem Int Ed 57:5765–5771
Chauhan DK, Jain S, Battula VR, Kailasam K (2019) Organic motif’s functionalization via covalent linkage in carbon nitride: an exemplification in photocatalysis. Carbon 152:40–58
Lau VW-h, Mesch MB, Duppel V, Blum V, Senker J, Lotsch BV (2015) Low-molecular-weight carbon nitrides for solar hydrogen evolution. J Am Chem Soc 137:1064–1072
Frisch M, Trucks G, Schlegel HB, Scuseria G, Robb M, Cheeseman J, Scalmani G, Barone V, Mennucci B, Petersson G (2009) Gaussian 09, revision D. 01. Gaussian, Inc., Wallingford CT
Yanai T, Tew DP, Handy NC (2004) A new hybrid exchange-correlation functional using the Coulomb-attenuating method (CAM-B3LYP). Chem Phys Lett 393:51–57
Hariharan PC, Pople JA (1973) The influence of polarization functions on molecular orbital hydrogenation energies. Theoret Chim Acta 28:213–222
Adamo C, Jacquemin D (2013) The calculations of excited-state properties with time-dependent density functional theory. Chem Soc Rev 42:845–856
Chen S, Zhao Y, Ullah N, Wan Q, Zhang R (2019) Revealing the trap emission in graphene-based nanostructures. Carbon 150:439–445
Lu T, Chen F (2012) Multiwfn: a multifunctional wavefunction analyzer. J Comput Chem 33:580–592
Chen S, Ullah N, Wang T, Zhang R-Q (2018) Tuning optical properties of graphene quantum dots by selective oxidation: a theoretical perspective. J Mater Chem C 6:6875–6883
Powell LR, Piao Y, Ng AL, Wang Y (2018) Channeling excitons to emissive defect sites in carbon nanotube semiconductors beyond the dilute regime. J Phys Chem Lett 9:2803–2807
Zhu S, Zhang J, Tang S, Qiao C, Wang L, Wang H, Liu X, Li B, Li Y, Yu W, Wang X, Sun H, Yang B (2012) Surface chemistry routes to modulate the photoluminescence of graphene quantum dots: from fluorescence mechanism to up-conversion bioimaging applications. Adv Funct Mater 22:4732–4740
Xiao J, Han Q, Xie Y, Yang J, Su Q, Chen Y, Cao H (2017) Is C3N4 chemically stable toward reactive oxygen species in sunlight-driven water treatment? Environ Sci Technol 51:13380–13387
Chen S, Ullah N, Zhao Y, Zhang R (2019) Nonradiative excited-state decay via conical intersection in graphene nanostructures. ChemPhysChem 20:2754–2758
Kilina S, Ramirez J, Tretiak S (2012) Brightening of the lowest exciton in carbon nanotubes via chemical functionalization. Nano Lett 12:2306–2312
Zhou Z, Shen Y, Li Y, Liu A, Liu S, Zhang Y (2015) Chemical cleavage of layered carbon nitride with enhanced photoluminescent performances and photoconduction. ACS Nano 9:12480–12487
Chen S, Ullah N, Zhang R-Q (2018) Exciton self-trapping in sp 2 carbon nanostructures induced by edge ether groups. J Phys Chem Lett 9:4857–4864
Wang H, Jiang S, Chen S, Li D, Zhang X, Shao W, Sun X, Xie J, Zhao Z, Zhang Q, Tian Y, Xie Y (2016) Enhanced singlet oxygen generation in oxidized graphitic carbon nitride for organic synthesis. Adv Mater 28:6940–6945
Ullah N, Chen S, Zhang R (2019) Mechanism of the charge separation improvement in carbon-nanodot sensitized g-C3N4. Appl Surf Sci 487:151–158
This work was financially supported by the Grants from Qilu University of Technology (Shandong Academy of Sciences), Colleges and Universities Twenty Terms Foundation of Jinan City (2019GXRC034), and National Natural Science Foundation of China (11874081).
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Chen, S., Ullah, N. & Zhang, R. Engineering the excited state of graphitic carbon nitride nanostructures by covalently bonding with graphene quantum dots. Theor Chem Acc 139, 20 (2020). https://doi.org/10.1007/s00214-019-2525-z
- Carbon nitride
- Graphene quantum dots
- Covalent bonding
- Exciton distributions