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Solar Cell Characterization

Solar Cell Characterization

Optical Insights into Carrier Dynamics and Material Properties

Investigating charge-carrier lifetimes and recombination dynamics to enable precise optical characterization of material quality and device performance.
Image of a solar cell surface structure used for optical characterization of charge carrier dynamics and recombination processes.
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Advancing Photovoltaic Materials through Optical Characterization

Understanding Solar Cell Research

Solar cells are mainly made of semiconductor devices that convert light into electrical energy. Their performance depends on how efficiently photo-generated charge carriers are created, transported, and collected. Understanding these processes requires precise optical characterization techniques that unveil the material’s structural and electronic properties.

Current research in solar cell characterization increasingly focuses on how material composition and structure influence device efficiency and long-term stability. Optical techniques, especially time-resolved photoluminescence (TRPL), provide insight into charge-carrier dynamics, nonradiative recombination, and defect behavior. By linking these photophysical properties to processing conditions, researchers can accelerate the development of high-performance solar cell materials. Below are some of the most actively studied material classes in photovoltaic research.

Time-Resolved Optical Characterization of Solar Cells

Time-resolved photoluminescence (TRPL) reveals how charge carriers recombine after photoexcitation, providing direct insight into recombination dynamics and defect-related losses. TRPL imaging extends this approach by adding spatial resolution, enabling the visualization of local variations in lifetime, transport, and material quality. Additional time-resolved and spatially resolved techniques, such as carrier diffusion imaging, further complement this analysis and broaden access to transport-related properties relevant for solar cell performance.

Position-Dependent Steady-State and Time-Resolved PL Spectroscopy

Steady-state and time-resolved photoluminescence measurements at different locations on a CIGS solar cell reveal how local device geometry influences carrier dynamics. Using a FluoTime 300 spectrometer combined with the FluoMic microscope, PL spectra and lifetimes were recorded near silver grid lines and between contacts, demonstrating how excitation and detection volume affect extracted lifetimes and recombination behavior.

Influence of Activation Treatments Studied by TRPL Imaging

Time-resolved photoluminescence imaging was used to analyze the impact of chloride activation on polycrystalline CdTe wafers. Using a MicroTime 200 confocal microscope, intensity and lifetime maps recorded before and after thermal treatment reveal a pronounced increase in photoluminescence intensity and carrier lifetime. Spatially resolved TRPL data uncover heterogeneous improvements across the CdTe structure, even at millisecond-scale acquisition times.

Application Examples in Solar Cell Research

Perovskite solar cells are among the most promising thin-film materials, combining high efficiencies, low-temperature processing, and tunable bandgaps. Key challenges include environmental instability, nonradiative recombination at grain boundaries, and film heterogeneity. Optical characterization methods, particularly time-resolved photoluminescence (TRPL) and TRPL imaging, provide insight into charge-carrier dynamics, diffusion behavior, and localized defect states. Correlating lifetime variations with processing conditions helps identify degradation pathways and supports the development of more stable, high-performance perovskite absorbers.

Absorption spectra, photoluminescence emission, and TRPL decay curves of perovskite solar cell films showing reduced nonradiative recombination after additive treatment.

Characterizing Carrier Recombination with TRPL Spectroscopy

Time-resolved photoluminescence spectroscopy was used to assess how the molecular additive 3API improves perovskite solar cell stability. Increased steady-state PL intensity and prolonged TRPL decay measured with a FluoTime 300 indicate suppressed nonradiative recombination, directly linking material modification to enhanced optoelectronic quality.

Time-resolved photoluminescence lifetime maps of wrinkled perovskite films showing spatial differences in carrier dynamics between hill and valley regions.

TRPL Imaging of Perovskite Layer Morphology

Time-resolved photoluminescence imaging was used to study micro-wrinkled perovskite layers with composition-controlled morphology. TRPL maps acquired with a MicroTime 200 reveal pronounced lifetime differences between hill and valley regions, directly linking local film structure to modified carrier dynamics and enhanced photocurrent generation.

Photoluminescence quantum yield and decay curves measured at different excitation pulse energies and repetition rates in perovskite solar cell materials.

Mapping Photoluminescence Quantum Yield

Photoluminescence quantum yield mapping was applied to evaluate the validity of recombination models in metal halide perovskites. By systematically varying excitation pulse energy and repetition rate over several orders of magnitude, spatially resolved PLQY measurements enable quantitative comparison between experimental results and theoretical recombination models.

Copper Indium Gallium Selenide (CIGS)

Copper Indium Gallium Selenide (Cu(In,Ga)Se₂, CIGS) solar cells represent a mature thin-film technology with strong optical absorption, cost-effective material utilization and compatibility with flexible substrates. Research focuses on how composition, interface quality, and post-deposition treatments influence carrier dynamics and device efficiency. Optical characterization methods, particularly TRPL and TRPL imaging, provide quantitative insight into carrier lifetimes, recombination pathways, and spatial inhomogeneities, enabling correlations between local electronic properties and macroscopic device performance.

Photoluminescence decay curves recorded at different excitation intensities revealing trap-state saturation and recombination dynamics in CIGS solar cells.

Power-Dependent TRPL Imaging of CIGS Solar Cells

TRPL imaging at varying excitation power densities reveals how trap-state saturation affects carrier recombination in CIGS devices. At higher excitation levels, photoluminescence images become more homogeneous and lifetimes increase, highlighting the strong dependence of recombination dynamics on excitation conditions.

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

TRPL Imaging of Weakly Luminescent CIGS Using SNSPD Detection

Time-resolved confocal imaging with superconducting nanowire single-photon detectors enables TRPL analysis of weakly luminescent CIGS solar cells in the near-infrared. High detection efficiency and picosecond timing resolution reveal distinct decay profiles at defect and non-defect regions, even at low excitation intensities.

Cadmium Telluride (CdTe)

CdTe solar cells are a well-established thin-film technology valued for scalability, cost efficiency, and strong optical absorption. Research targets the reduction of nonradiative losses, improved grain-boundary passivation, and control of deep-level defects. TRPL and TRPL imaging enable analysis of carrier recombination dynamics, identification trap-assisted processes and treatment effects, linking material quality to device performance and long-term stability.

Photoluminescence decay curves measured at the surface and near the pn-junction of a CdTe solar cell showing differences in carrier recombination lifetimes.

Carrier Dynamics Near the pn-Junction Revealed by TRPL Imaging

Time-resolved confocal imaging of CdTe solar cell cross sections reveals how carrier lifetimes vary from the surface toward the pn-junction. TRPL measurements show a gradual lifetime increase across the junction region, demonstrating that photoluminescence intensity alone does not directly reflect recombination dynamics.

Other Emerging Materials

Other photovoltaic materials such as organic, quantum dot, and tandem architectures are also under active research. Time-resolved techniques like TRPL provide key insights into carrier dynamics and recombination across these systems, demonstrating their broad applicability for characterizing emerging solar cell technologies.

Photoluminescence Measurements

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Matching Methods

All Applications & 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.
Materials Science

Time-Resolved Photoluminescence (TRPL) Imaging

TRPL decay curves showing different lifetimes
Materials Science

Time-Resolved Photoluminescence (TRPL)

Carrier diffusion imaging in a quantum well structure
Materials Science

Carrier Diffusion Imaging

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: Multimodal Microscopy of Halide Perovskite Solar Cells

In this video, Sam Stranks (University of Cambridge), gives an overview of halide perovskite solar cell research using multimodal microscopy to study luminescence, recombination, degradation, and pathways to improve efficiency and stability.

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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.

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Application Note: Time-Resolved Fluorescence Spectroscopy and Microscopy

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

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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.

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Application Note: Measuring Steady-state and Time-Resolved Photoluminescence

Learn how time-resolved fluorescence techniques reveal excited-state dynamics and charge-carrier processes in materials.

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Poster: TRPL Mapping

TRPL mapping of CIGS devices using a combination of a superconducting nanowire detector and a confocal microscope

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