14 research outputs found
Direct Observation of Charge Collection at Nanometer-Scale Iodide-Rich Perovskites during Halide Exchange Reaction on CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub>
Organolead halide
perovskites MAPbX<sub>3</sub> (MA = CH<sub>3</sub>NH<sub>3</sub><sup>+</sup>, X = Cl<sup>β</sup>, Br<sup>β</sup>, or I<sup>β</sup>) are known to undergo reversible halide
exchange reactions, enabling bandgap tuning over the visible light
region. Using single-particle photoluminescence (PL) imaging for in
situ observation, we have studied the structure-dependent charge dynamics
during halide exchange with iodide ions on an MAPbBr<sub>3</sub> crystal.
In particular, we optically detected nanometer-scale iodide-rich domains
(i.e., MAPbBrI<sub>2</sub>) and found that their lifetimes of several
tens of milliseconds are limited by reaction with diffusing vacancies.
Furthermore, it was discovered that these domains effectively collect
the charge carriers from the bulk crystal, thus resulting in amplified
spontaneous emission (ASE) under continuous-wave laser irradiation.
Our findings will provide direction for development of perovskite
heterostructures with enhanced charge utilization
Surface Charge Trapping in Organolead Halide Perovskites Explored by Single-Particle Photoluminescence Imaging
Organometal halide perovskites have
attracted considerable attention
because of their striking electrical and optical properties that are
desirable for application in solar cells and optoelectronic devices;
however, the structure-related dynamics of photogenerated charges
are almost always masked by ensemble averaging in conventional spectroscopic
methods, making it difficult to clarify the underlying mechanism.
Here we investigate the photoluminescence characteristics of CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> perovskite nanoparticles using
single-particle spectroscopy combined with electron microscopy. The
in situ analysis of light and Lewis-base-induced surface passivation
revealed that the photoluminescence quenching and blinking phenomena
of single CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> nanoparticles
are most probably caused by charge trapping at surface states, where
the number of effective trapping sites was estimated to be 1β4
per particle
Direct Observation of Charge Collection at Nanometer-Scale Iodide-Rich Perovskites during Halide Exchange Reaction on CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub>
Organolead halide
perovskites MAPbX<sub>3</sub> (MA = CH<sub>3</sub>NH<sub>3</sub><sup>+</sup>, X = Cl<sup>β</sup>, Br<sup>β</sup>, or I<sup>β</sup>) are known to undergo reversible halide
exchange reactions, enabling bandgap tuning over the visible light
region. Using single-particle photoluminescence (PL) imaging for in
situ observation, we have studied the structure-dependent charge dynamics
during halide exchange with iodide ions on an MAPbBr<sub>3</sub> crystal.
In particular, we optically detected nanometer-scale iodide-rich domains
(i.e., MAPbBrI<sub>2</sub>) and found that their lifetimes of several
tens of milliseconds are limited by reaction with diffusing vacancies.
Furthermore, it was discovered that these domains effectively collect
the charge carriers from the bulk crystal, thus resulting in amplified
spontaneous emission (ASE) under continuous-wave laser irradiation.
Our findings will provide direction for development of perovskite
heterostructures with enhanced charge utilization
Direct Observation of Charge Collection at Nanometer-Scale Iodide-Rich Perovskites during Halide Exchange Reaction on CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub>
Organolead halide
perovskites MAPbX<sub>3</sub> (MA = CH<sub>3</sub>NH<sub>3</sub><sup>+</sup>, X = Cl<sup>β</sup>, Br<sup>β</sup>, or I<sup>β</sup>) are known to undergo reversible halide
exchange reactions, enabling bandgap tuning over the visible light
region. Using single-particle photoluminescence (PL) imaging for in
situ observation, we have studied the structure-dependent charge dynamics
during halide exchange with iodide ions on an MAPbBr<sub>3</sub> crystal.
In particular, we optically detected nanometer-scale iodide-rich domains
(i.e., MAPbBrI<sub>2</sub>) and found that their lifetimes of several
tens of milliseconds are limited by reaction with diffusing vacancies.
Furthermore, it was discovered that these domains effectively collect
the charge carriers from the bulk crystal, thus resulting in amplified
spontaneous emission (ASE) under continuous-wave laser irradiation.
Our findings will provide direction for development of perovskite
heterostructures with enhanced charge utilization
Surface Charge Trapping in Organolead Halide Perovskites Explored by Single-Particle Photoluminescence Imaging
Organometal halide perovskites have
attracted considerable attention
because of their striking electrical and optical properties that are
desirable for application in solar cells and optoelectronic devices;
however, the structure-related dynamics of photogenerated charges
are almost always masked by ensemble averaging in conventional spectroscopic
methods, making it difficult to clarify the underlying mechanism.
Here we investigate the photoluminescence characteristics of CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> perovskite nanoparticles using
single-particle spectroscopy combined with electron microscopy. The
in situ analysis of light and Lewis-base-induced surface passivation
revealed that the photoluminescence quenching and blinking phenomena
of single CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> nanoparticles
are most probably caused by charge trapping at surface states, where
the number of effective trapping sites was estimated to be 1β4
per particle
Surface Charge Trapping in Organolead Halide Perovskites Explored by Single-Particle Photoluminescence Imaging
Organometal halide perovskites have
attracted considerable attention
because of their striking electrical and optical properties that are
desirable for application in solar cells and optoelectronic devices;
however, the structure-related dynamics of photogenerated charges
are almost always masked by ensemble averaging in conventional spectroscopic
methods, making it difficult to clarify the underlying mechanism.
Here we investigate the photoluminescence characteristics of CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> perovskite nanoparticles using
single-particle spectroscopy combined with electron microscopy. The
in situ analysis of light and Lewis-base-induced surface passivation
revealed that the photoluminescence quenching and blinking phenomena
of single CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> nanoparticles
are most probably caused by charge trapping at surface states, where
the number of effective trapping sites was estimated to be 1β4
per particle
Determination of the fine structure of a halide perovskite using THz spectroscopy
In a crystalline solid, many types of disorders exist. Revealing the localized structures induced by disorder is one of the central issues of crystallography. Retrieving information about disorder from the scattering patterns of X-ray and/or neutron diffractions is still facing vital challenges. New experimental observations, whenever available, are greeted to shed additional light on this problem. We have in one previous work demonstrated a ubiquitous capability of terahertz (THz) spectroscopy to detect the fingerprint vibrational peaks of correlated molecular arrangements at the nano-scale level in an occupation disorder system.[1] We will, in this work, employ THz spectroscopy to study the fine structure of the halide perovskite systems where the short-range order of the disordered methylammonium (MA) molecules remains an open question.Published versio