Products
Applications & Methods
Search

Products

Application & Methods

Home >
Applications & Methods >
Carrier Diffusion Imaging

Carrier Diffusion Imaging

Visualizing Charge Carrier Transport in Materials

An imaging technique that visualizes charge carrier diffusion to reveal transport dynamics in materials.
Carrier diffusion imaging in a quantum well structure
Table of contents

Understanding Charge Carrier Transport at the Nanoscale

What is Carrier Diffusion Imaging?

Carrier diffusion imaging is an optical approach that visualizes how photoexcited charge carriers spread through a material over time. By mapping their spatial evolution, it reveals transport inhomogeneities arising from defects, interfaces, or compositional variations. This insight is crucial for functional materials such as semiconductors and solar cells, where carrier diffusion length and mobility strongly affect device performance.

How does Carrier Diffusion Imaging work?

Carrier diffusion imaging is not a single technique but a measurement concept that can be realized using time-resolved optical microscopy. A common implementation employs time-resolved photoluminescence imaging (TRPL Imaging), where spatially resolved fluorescence lifetime information reveals how charge carriers redistribute after excitation and enables visualization of carrier transport. Complementarily, transient absorption microscopy (TAM) probes carrier diffusion through changes in optical absorption, providing access to non-radiative and dark states not observable in photoluminescence.

Carrier Diffusion Imaging Data & Analysis

Typical carrier diffusion imaging datasets consist of time-resolved intensity or lifetime maps recorded across the sample. From the temporal evolution of these maps, the broadening of the carrier distribution can be quantified, yielding parameters such as the diffusion coefficient and diffusion length. Such analysis enables direct comparison between different sample regions or materials. Time-resolved carrier diffusion analysis further allows the separation of transport dynamics from recombination effects, supporting a deeper understanding of spatially heterogeneous materials.

PicoQuant software for Carrier Diffusion Imaging analysis

PicoQuant’s EasyTau 2 software enables intuitive TRPL data acquisition and decay analysis, with integrated fitting, reconvolution, and batch processing tools in a single streamlined workflow.

Why use Carrier Diffusion Imaging?

Carrier diffusion imaging provides direct insight into charge transport on a spatially resolved level, making it highly valuable for semiconductor, solar cell, and nanomaterials research. It is increasingly applied to study carrier transport in two-dimensional materials, polymers, and hybrid systems, as well as for LED characterization and new material development. By revealing diffusion bottlenecks, defects, and interface effects, the technique supports materials optimization and device development. Unlike bulk measurements, carrier diffusion imaging captures local heterogeneity, making it an essential tool for modern materials science and optoelectronic research.

Instrumentation requirements for Carrier Diffusion Imaging

Reliable carrier diffusion imaging requires precisely synchronized, time-resolved excitation and detection. Short-pulse laser sources initiate localized carrier populations, while sensitive detectors capture their spatial and temporal evolution. Stable optical alignment and precise synchronization are critical for extracting time-resolved carrier diffusion parameters. Depending on implementation, the system must offer fast imaging, broad dynamic range, and flexible data acquisition to generate quantitative diffusion maps across diverse materials.

Photoluminescence Measurements

Compact Wavelength Selection with FlexLambda Kit

Software-controlled wavelength selector for visible and NIR spectral range, high transmission rate for highest sensitivity, compatible with widefield and confocal microscopes.
Learn more
FlexLambda Kit: Compact Wavelength Selection Unit
Relevant for Your Research​

Matching Applications

All Applications & Methods
Schematic illustration of nanostructured materials on a substrate highlighting heterogeneous nanoscale architectures studied by optical and time-resolved characterization.
Materials Science

Nanomaterials Research

illustration of a van der Waals heterostructure emitting quantum light
Materials Science

2D Materials Research

Time-resolved photoluminescence emission spectrum showing three peaks from different semiconductor layers, illustrating layer-specific recombination dynamics.
Materials Science

Semiconductor Research

Application Examples

The following examples demonstrate how carrier diffusion imaging enables quantitative analysis of charge carrier diffusion and transport heterogeneity in semiconductors and photovoltaic materials using time-resolved photoluminescence techniques.

Carrier diffusion imaging in quantum well using TRPL

Micro-Photoluminescence Upgrade for Carrier Diffusion Imaging

The Micro-Photoluminescence Upgrade integrates time-resolved photoluminescence with confocal scanning to enable quantitative carrier diffusion imaging. It supports spatially resolved carrier diffusion mapping and extraction of diffusion parameters such as carrier diffusion length and diffusion coefficient in advanced semiconductor and photovoltaic materials.

TRPL intensity and lifetime imaging of CdTe wafers before and after thermal activation

Carrier Diffusion Imaging in Quantum Wells

Under pulsed excitation, spatially resolved time-resolved photoluminescence imaging reveals how charge carriers spread from a localized generation region. Analysis of decay curves from multiple regions of interest enables quantitative extraction of carrier diffusion length and diffusion coefficient in layered semiconductor structures.

Related Methods

Excitation and emission spectra of fluorescence polymer reference materials SFG and SFO measured with a microscope-based photoluminescence setup.

Photoluminescence (PL)

A steady-state spectroscopy method that measures the intensity of light emitted from a material under continuous excitation. It provides insights into electronic band structure, defect states, and optical quality but does not capture temporal emission dynamics.

TRPL decay curves showing different lifetimes

Time-Resolved Photoluminescence (TRPL)

A time-resolved spectroscopy technique that measures the temporal decay of photoluminescence after pulsed excitation. It reveals charge carrier lifetimes and recombination dynamics but does not provide the spatially resolved transport information accessible with imaging-based methods.

Time-resolved photoluminescence image and decay curves of a CIGS solar cell measured using superconducting nanowire single-photon detectors revealing defect-related recombination dynamics.

Time-Resolved Photoluminescence (TRPL) Imaging

A spatially resolved time-resolved technique that combines photoluminescence lifetime measurements with confocal or scanning microscopy. It maps charge carrier lifetimes across a sample, enabling visualization of spatial transport inhomogeneities and providing the basis for carrier diffusion imaging and diffusion parameter extraction.

In-Depth Scientific Resources

Premium Resources

Access in-depth application notes and scientific posters with detailed methods, measurement data, and real-world use cases.

Customer Video: Study of Defects in Metal Halide Perovskites

In this customer video, Prof. Jinsong Huang (University of North Carolina) discusses how electronic defects affect efficiency and stability in perovskite solar cells and how FLIM helps visualize their impact.

Download

Poster: High Spatial Photoluminescence Investigation of Nanostructures

Poster on high-spatial photoluminescence studies of nanostructures and quantum emitters using time-resolved confocal microscopy and spectroscopy.

Download

Poster: Photoluminescence Analysis of PV Devices

Poster on non-destructive photoluminescence analysis of PV devices using TRPL microscopy to study carrier dynamics, diffusion and material properties.

Download

Application Note: Wafer Characterization

Application note on wafer characterization using time-resolved photoluminescence and TCSPC to analyze charge carrier dynamics in semiconductor materials.

Download

Application Note: Time-Resolved Fluorescence Spectroscopy and Microscopy

How time-resolved fluorescence spectroscopy and microscopy reveal excited-state dynamics, defects, and charge-carrier processes

Download

Download

Request your file

Please fill out the form below to receive the requested file. After submitting your details, the file will be sent to you by email.

* Required

Consent*
Scientific Insights & Resources

Latest Blog Articles

Visit our science hub
Info Request
Enter search term

Info Request

Contact us

Please fill out the form below to request more information about our products and services. You may also use it to ask for pricing, availability, technical specifications, or any other details relevant to your inquiry. Our team will be happy to review your request and get in touch with you. If additional information is needed to process your inquiry, we will let you know.

* Required

Consent*

Contact us

Please fill out the form below to request more information and prices about our product. Our team will be happy to review your request and get in touch with you. If additional information is needed to process your inquiry, we will let you know.

* Required

Consent*