Influence of mixed organic cations on the
nonlinear optical properties of lead
tri-iodide perovskites
XUANYU ZHANG,
1
SHUYU XIAO,
2
RUXUE LI,
1
TINGCHAO HE,
2,5
GUICHUAN XING,
3,6
AND RUI CHEN
1,4,7
1
Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
2
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
3
Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau,
Avenida da Universidade, Taipa, Macau 999078, China
4
Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education,
Shenzhen 518055, China
5
e-mail: tche@szu.edu.cn
6
e-mail: gcxing@um.edu.mo
7
e-mail: chenr@sustech.edu.cn
Received 1 June 2020; revised 1 July 2020; accepted 1 July 2020; posted 7 July 2020 (Doc. ID 398975); published 17 August 2020
Metal halide perovskite materials have been widely studied recently due to their excellent optoelectronic prope r-
ties. Among these materials, organic-inorganic hybrid perovskites have attracted much attention because of their
relatively soft framework, which makes them more suitable for nonlinear optical (NLO) applications. However,
there is rare physical mechanism study on the coexistence of two-photon absorption (TPA) and saturable ab-
sorption (SA) in organic-inorganic hybrid perovskite materials. To clarify this issue, the NLO properties of mixed
cation perovskite MA
1−x
FA
x
PbI
3
MA CH
3
NH
3
, FA CHNH
2
2
, x 0, 0.2, 0.4, 0.6, and 0.8] thin films are
investigated in this paper. Based on the nonlinear transmittance and femtosecond-transient absorption spectrum
measurements, it is found that the MA
1−x
FA
x
PbI
3
materials exhibit NLO behavior dependent on excitation in-
tensity. The TPA coefficient of MA
1−x
FA
x
PbI
3
decreases with the increase of formamidinium (FA) content, while
the relevant saturable intensity increases. In addition, it is revealed that the linear absorption process from valence
band 2 to valance band 1 still exists even under a very low excitation intensity. With the increase of excitation
intensity, the light transmittance at 1300 nm decreases first and then increases sharply, which also supports the
explanation for the coexistence of TPA and SA. It is expected that our findings will promote the application of
perovskite materials in nonlinear optoelectronic devices.
© 2020 Chinese Laser Press
https://doi.org/10.1364/PRJ.398975
1. INTRODUCTION
Organic-inorganic halide perovskite materials have attracted
great interest due to outstanding optoelectronic properties,
such as high carrier mobility [1], as well as tunable photolumi-
nescence (PL) properties [2]. At present, perovskite materials
have already achieved great success in the field of photovoltaics.
For example, the efficiency of perovskite solar cells can be up to
25.2% [3], which is comparable to that of polycrystalline sil-
icon solar cells [4]. Meanwhile, perovskite materials have been
widely used for light-emitting diodes [5,6]. Recently, the excel-
lent nonlinear optical (NLO) properties of organic-inorganic
halide perovskite materials have increasingly attracted attention
[7]. It is well known that the origi nal molecular polarization
of materials resulting from charge transfer between the mole-
cular portion A and BX
3
in perovskite exhibits the electron
cloud distortio n under intensive light, which leads to NLO
properties [8]. Compared with all-inorganic perovskite materi-
als, the organic-inorganic hybrid perovskite with a softer frame-
work allows for the change of A-cation orientation, which may
enhance the optical nonlinearity. For instance, a comparative
study on the NLO properties of colloidal MAPbBr
3
MA
CH
3
NH
3
and CsPbBr
3
quantum dots (QDs) was conducted
by Lu et al., proving that the nonlinear absorption character-
istics of organic-inorganic hybrid perovskite QDs are much
more pronounced than those of all-inorganic perovskite
QDs because of the photoinduced orientation effects [9].
Suárez et al. studied the NLO properties of MAPbX
3
poly-
crystalline thin films [10]. It was found that both the nonlinear
absorption coefficient (β) and the nonlinear refraction index (n)
of organic-inorganic halide perovskite thin films are three to
four orders of magnitude larger than that of all-inorganic per-
ovskite CsPbX
3
, which shows more potential in the field of
Research Article
Vol. 8, No. 9 / September 2020 / Photonics Research A25
2327-9125/20/090A25-06 Journal © 2020 Chinese Laser Press
资源评论
