Graphitic carbon nitride (g-C3N4), a metal-free and visible light responsive photocatalyst, has garnered much attention due to its wide range of applications. In order to elucidate the role of dimensionality on the properties of photo-generated charge carriers, we apply nonadiabatic (NA) molecular dynamics combined with time-domain density functional theory to investigate nonradiative relaxation of hot electrons and holes, and electron–hole recombination in monolayer and bulk g-C3N4. The nonradiative charge recombination occurs on a nanosecond timescale and is faster in bulk than the nanosheet, in agreement with the experiment. The difference arises due to the smaller energy gap and participation of additional vibrations in the bulk system. The long carrier lifetimes are favored by small NA coupling and rapid phonon-induced loss of quantum coherence between the excited and ground electronic states. Decoherence is fast because g-C3N4 is soft and undergoes large scale vibrations. The NA coupling is small since electrons and holes are localized on different atoms, and the electron–hole overlap is relatively small. Phonon-driven relaxation of hot electrons and holes takes 100–200 fs and is slightly slower at higher initial energies due to participation of fewer vibrational modes. This feature of two-dimensional g-C3N4 contrasts traditional three-dimensional semiconductors, which exhibit faster relaxation at higher energies due to larger density of states, and can be used to extract hot carriers to perform useful functions. The ab initio quantum dynamics simulations present a comprehensive picture of the photo-induced charge carrier dynamics in g-C3N4, guiding design of photovoltaic and photocatalytic devices.

1.
R.
Mas-Ballesté
et al.,
Nanoscale
3
,
20
(
2011
).
3.
K.
Momeni
 et al.,
npj Comput. Mater.
6
,
22
(
2020
).
4.
M.
Osada
and
T.
Sasaki
,
J. Mater. Chem.
19
,
2503
(
2009
).
5.
Q. H.
Wang
et al.,
Nat. Nanotechnol.
7
,
699
(
2012
).
6.
X.
Peng
et al.,
Chem. Soc. Rev.
43
,
3303
(
2014
).
7.
Y.
Sun
,
S.
Gao
, and
Y.
Xie
,
Chem. Soc. Rev.
43
,
530
(
2014
).
8.
A.
Hasani
 et al.,
J. Mater. Chem. A
7
,
430
(
2019
).
9.
X.
Wang
 et al.,
Nat. Mater.
8
,
76
(
2009
).
10.
J.
Zhu
et al.,
ACS Appl. Mater. Interfaces
6
,
16449
(
2014
).
11.
W.-J.
Ong
et al.,
Chem. Rev.
116
,
7159
(
2016
).
12.
L.
Zhou
et al.,
Catal. Sci. Technol.
6
,
7002
(
2016
).
13.
A.
Wang
 et al.,
Nano-Micro Lett.
9
,
47
(
2017
).
14.
15.
J.
Ehrmaier
,
W.
Domcke
, and
D.
Opalka
,
J. Phys. Chem. Lett.
9
,
4695
(
2018
).
16.
G. O.
Hartley
and
N.
Martsinovich
,
Faraday Discuss.
(published online
2020
).
17.
N.
Rono
 et al., (
Taylor & Francis
,
2020
), Vol. 57, p.
1
.
18.
J.
Liu
,
H.
Wang
, and
M.
Antonietti
,
Chem. Soc. Rev.
45
,
2308
(
2016
).
19.
B.
Mortazavi
,
G.
Cuniberti
, and
T.
Rabczuk
,
Comput. Mater. Sci.
99
,
285
(
2015
).
20.
21.
R.
Guo
,
G.
Zhao
, and
S.
Wang
,
J. Phys. D: Appl. Phys.
52
,
385107
(
2019
).
22.
L.
Sun
et al.,
J. Mater. Chem.
22
,
23428
(
2012
).
23.
M.
Makaremi
et al.,
ACS Appl. Mater. Interfaces
10
,
11143
(
2018
).
24.
J.
Wang
 et al.,
J. Mater. Chem. A
2
,
7960
(
2014
).
25.
W.
Wei
and
T.
Jacob
,
Phys. Rev. B
87
,
085202
(
2013
).
26.
J.
Xu
et al.,
J. Mater. Chem. A
1
,
14766
(
2013
).
28.
A.
Shi
et al.,
Appl. Catal. B: Environ.
218
,
137
(
2017
).
29.
C.
Ye
 et al.,
ACS Catal.
5
,
6973
(
2015
).
30.
G.
Wang
 et al.,
ACS Appl. Mater. Interfaces
8
,
24509
(
2016
).
31.
M.-H.
Chan
,
R.-S.
Liu
, and
M.
Hsiao
,
Nanoscale
11
,
14993
(
2019
).
32.
Q.
Guo
 et al.,
J. Mater. Chem. C
4
,
6839
(
2016
).
33.
Q.
Lin
et al.,
Appl. Catal. B: Environ.
163
,
135
(
2015
).
34.
B.
Lin
 et al.,
Appl. Catal. B: Environ.
210
,
173
(
2017
).
35.
G.
Liao
et al.,
Energy Environ. Sci.
12
,
2080
(
2019
).
36.
D. J.
Trivedi
,
L.
Wang
, and
O. V.
Prezhdo
,
Nano Lett.
15
,
2086
(
2015
).
37.
K.
Hyeon-Deuk
,
J.
Kim
, and
O. V.
Prezhdo
,
J. Phys. Chem. Lett.
6
,
244
(
2015
).
38.
O. V.
Prezhdo
,
Chem. Phys. Lett.
460
,
1
(
2008
).
39.
40.
E.
Runge
and
E. K. U.
Gross
,
Phys. Rev. Lett.
52
,
997
(
1984
).
41.
C. F.
Craig
,
W. R.
Duncan
, and
O. V.
Prezhdo
,
Phys. Rev. Lett.
95
,
163001
(
2005
).
42.
S. A.
Fischer
et al.,
J. Chem. Phys.
134
,
024102
(
2011
).
43.
J. R.
Schmidt
,
P. V.
Parandekar
, and
J. C.
Tully
,
J. Chem. Phys.
129
,
044104
(
2008
).
44.
J. C.
Tully
,
J. Chem. Phys.
93
,
1061
(
1990
).
45.
D. J.
Trivedi
and
O. V.
Prezhdo
,
J. Phys. Chem. A
119
,
8846
(
2015
).
46.
S. V.
Kilina
 et al.,
Phys. Rev. Lett.
110
,
180404
(
2013
).
47.
O. V.
Prezhdo
and
P. J.
Rossky
,
J. Chem. Phys.
107
,
5863
(
1997
).
48.
H. M.
Jaeger
,
S.
Fischer
, and
O. V.
Prezhdo
,
J. Chem. Phys.
137
,
22A545
(
2012
).
49.
O. V.
Prezhdo
,
J. Chem. Phys.
111
,
8366
(
1999
).
50.
E. R.
Bittner
and
P. J.
Rossky
,
J. Chem. Phys.
103
,
8130
(
1995
).
51.
S.
Mukamel
,
Principles of Nonlinear Optical Spectroscopy
(
Oxford University Press
,
1999
), on Demand, p.
6
.
52.
L.
Li
,
R.
Long
, and
O. V.
Prezhdo
,
Chem. Mater.
29
,
2466
(
2017
).
53.
A. V.
Akimov
and
O. V.
Prezhdo
,
J. Am. Chem. Soc.
136
,
1599
(
2014
).
54.
R.
Long
and
O. V.
Prezhdo
,
J. Am. Chem. Soc.
136
,
4343
(
2014
).
55.
L.
Wang
 et al., in
Green Processes for Nanotechnology: From Inorganic to Bioinspired Nanomaterials
, edited by
V. A.
Basiuk
and
E. V.
Basiuk
(
Springer International Publishing
,
Cham
,
2015
), p.
353
.
56.
Z.
Zhang
et al.,
J. Chem. Phys.
152
,
064707
(
2020
).
57.
B.
Barrow
and
D. J.
Trivedi
,
Computational Photocatalysis: Modeling of Photophysics and Photochemistry at Interfaces
(
American Chemical Society
,
2019
), p.
101
.
58.
R.
Long
and
O. V.
Prezhdo
,
ACS Nano
9
,
11143
(
2015
).
59.
V. V.
Chaban
,
V. V.
Prezhdo
, and
O. V.
Prezhdo
,
J. Phys. Chem. Lett.
4
,
1
(
2013
).
60.
L. J.
Wang
,
R.
Long
, and
O. V.
Prezhdo
, in
Annual Review of Physical Chemistry
, edited by
M. A.
Johnson
and
T. J.
Martinez2015
(
Annual Reviews
,
2015
), Vol. 66, p.
549
.
61.
W.
Chu
 et al.,
Angew. Chem., Int. Ed.
59
,
6435
(
2020
).
62.
C.-J.
Tong
et al.,
J. Am. Chem. Soc.
142
,
3060
(
2020
).
63.
W.
Li
et al.,
J. Phys. Chem. Lett.
10
,
6219
(
2019
).
64.
W.
Li
 et al.,
J. Phys. Chem. Lett.
10
,
3788
(
2019
).
65.
W.
Li
et al.,
J. Am. Chem. Soc.
140
,
15753
(
2018
).
66.
Y. T.
Wang
 et al.,
J. Phys. Chem. Lett.
10
,
1617
(
2019
).
67.
L. L.
Zhang
 et al.,
J. Phys. Chem. Lett.
10
,
1083
(
2019
).
68.
L.
Li
,
R.
Long
, and
O. V.
Prezhdo
,
Nano Lett.
18
,
4008
(
2018
).
69.
W.
Li
et al.,
J. Phys. Chem. Lett.
9
,
4006
(
2018
).
70.
G.
Kresse
and
J.
Furthmüller
,
Phys. Rev. B
54
,
11169
(
1996
).
71.
G.
Kresse
and
J.
Hafner
,
Phys. Rev. B
49
,
14251
(
1994
).
72.
G.
Kresse
and
J.
Hafner
,
Phys. Rev. B
47
,
558
(
1993
).
73.
J. P.
Perdew
,
K.
Burke
, and
M.
Ernzerhof
,
Phys. Rev. Lett.
77
,
3865
(
1996
).
74.
G.
Kresse
and
D.
Joubert
,
Phys. Rev. B
59
,
1758
(
1999
).
75.
J.
Klimeš
,
D. R.
Bowler
, and
A.
Michaelides
,
Phys. Rev. B
83
,
195131
(
2011
).
76.
J. P.
Perdew
,
Int. J. Quantum Chem.
28
,
497
(
1985
).
77.
A. V.
Krukau
et al.,
J. Chem. Phys.
125
,
224106
(
2006
).
78.
A. V.
Akimov
and
O. V.
Prezhdo
,
J. Chem. Theory Comput.
9
,
4959
(
2013
).
79.
A. V.
Akimov
and
O. V.
Prezhdo
,
J. Chem. Theory Comput.
10
,
789
(
2014
).
80.
S.
Zuluaga
et al.,
Phys. Chem. Chem. Phys.
17
,
957
(
2015
).
81.
L. M.
Azofra
,
D. R.
MacFarlane
, and
C.
Sun
,
Phys. Chem. Chem. Phys.
18
,
18507
(
2016
).
82.
Q.
Gao
 et al.,
J. Phys. Chem. C
124
,
4644
(
2020
).
83.
A.
Naseri
et al.,
J. Mater. Chem. A
5
,
23406
(
2017
).
84.
S. P.
Sun
 et al.,
J. Alloys Compd.
735
,
131
(
2018
).
85.
J.
Liu
and
E.
Hua
,
J. Phys. Chem. C
121
,
25827
(
2017
).
86.
K.
Momma
and
F.
Izumi
,
J. Appl. Crystallogr.
44
,
1272
(
2011
).
87.
W.
Chu
et al.,
J. Am. Chem. Soc.
142
,
3214
(
2020
).
88.
O. V.
Prezhdo
,
Phys. Rev. Lett.
85
,
4413
(
2000
).
89.
B. F.
Habenicht
et al.,
Nano Lett.
7
,
3260
(
2007
).
90.
H.
Kamisaka
et al.,
J. Phys. Chem. C
112
,
7800
(
2008
).
91.
A. J.
Neukirch
,
K.
Hyeon-Deuk
, and
O. V.
Prezhdo
,
Coord. Chem. Rev.
263-264
,
161
(
2014
).
93.
A. V.
Akimov
and
O. V.
Prezhdo
,
J. Phys. Chem. Lett.
4
,
3857
(
2013
).
94.
O. V.
Prezhdo
and
P. J.
Rossky
,
Phys. Rev. Lett.
81
,
5294
(
1998
).

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