Radiation-pressure-induced photoluminescence
enhancement of all-inorganic perovskite
CsPbBr
3
quantum dots
YING ZHANG,
1,2
HAIOU ZHU,
3
TAIWU HUANG,
1
ZONGPENG SONG,
2
AND SHUANGCHEN RUAN
2,3,
*
1
Center for Advanced Material Diagnostic Technology, College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China
2
Guangdong Provincial Key Laboratory of Mico/Nano Optomechatronics Engineering, College of Optoelectronic Engineering,
Shenzhen University, Shenzhen 518060, China
3
College of New Materials and New Energies, Shenzhen University of Technology, Shenzhen 518118, China
*Corresponding author: scruan@szu.edu.cn
Received 12 March 2019; revised 26 May 2019; accepted 26 May 2019; posted 28 May 2019 (Doc. ID 362245); published 12 July 2019
Perovskite quantum dots (QDs) are of great interest due to their outstanding optoelectronic properties and tre-
mendous application potential. Improving photoluminescence (PL) spectra in all-inorganic perovskite QDs is of
great importance for performance enhancement. In this work, the PL quantum yield of the CsPbBr
3
perovskite
QDs is enhanced from 70% to 95% with increasing radiation pressure. Such enhancement is attributed to the
increased binding energy of self-trapped excitons (STEs) upon radiation pressure, which is consistent with its
blue-shifted PL and other characterization results. Furthermore, we study ultrafast absorption spectroscopy
and find that the dynamics of relaxation from free excitons to STEs in radiation pressure CsPbBr
3
QDs is ascribed
to stronger electron–phonon coupling in the contracted octahedral structure. It is further demonstrated that
radiation pressure can boost the PL efficiency and explore effectively the relationship between the structure
and optical properties.
© 2019 Chinese Laser Press
https://doi.org/10.1364/PRJ.7.000837
1. INTRODUCTION
As is known, radiation pressure is the pressure exerted upon any
surface due to the exchange of momentum between the object
and the electromagnetic field. This includes the momentum of
light or electromagnetic radiation of any wavelength that is
absorbed, reflected, or otherwise emitted (e.g., black body
radiation) by matter on any scale [1–3]. Radiation pressure
is applied to the surface of the object, causing mechanical stress
on the object. Radiation pressure was proposed by Maxwell in
1864 and confirmed by Lebedev in 1901. The forces generated
by radiation pressure are important in some physical processes
and can find their appealing applications in many areas related
to the interaction between light and matter, which was con-
firmed by some research work in recent years [4–11]. It is a
meaningful thing to continue to seek and explore new physical
applications of radiation pressure.
Recently, inorganic perovskite materials have received exten-
sive attention for their excellent optical properties, good stabil-
ity, and low cost [12 –21]. They have extensive applications in
photovoltaic perovskite solar cells [22,23], light-emitting di-
odes [24–26], high-energy detectors [27–30], lasers [31– 34],
and other fields [35]. However, there are still some shortcom-
ings that significantly influence their optical and optoelectronic
properties and consequently, the device performance [36,37].
Improving photoluminescence (PL) spectra in all-inorganic
perovskite quantum dots (QDs) is of great importance for
high-performance perovskite devices. To enhance PL quantum
yield (PLQY), a series of methods has been proposed recently,
such as a solution-based hot-casting technique and an atomic
substitution doping technique [38–43]. Among different
mechanisms that improve the performance of inorganic perov-
skite, pressure-induced enhancement provides another attrac-
tive solution. Researchers Yasutaka et al. discovered that
luminescence properties and stability of the perovskite could
be improved by mechanical pressure, which induces regulation
on the degree of octahedron distortion of the halogen perov-
skite [44–46]. Now that the radiation pressure is one kind
of pressure, a similar positive phenomenon may also happen
when interacting with perovskite. However, the effect of radi-
ation pressure on the performance of inorganic perovskite QDs
is less investigated. So the difference between the effects of ra-
diation and mechanical pressure on the optical properties of
matter is an interesting topic.
In this study, radiation pressure is exploited to enhance the
performance of all-inorganic perovskite CsPbBr
3
QDs for the
first time, as far as we know. All-inorganic perovskite CsPbBr
3
QDs were irradiated by the 400 nm femtosecond laser under
different radiation pressures, and their optical performance to
Research Article
Vol. 7, No. 8 / August 2019 / Photonics Research 837
2327-9125/19/080837-10 Journal © 2019 Chinese Laser Press