Photovoltaics
Photovoltaics: Measurements and Lab Automation
Photovoltaic research today spans industrial crystalline silicon, rapidly evolving perovskite devices, highly efficient silicon perovskite tandems, and organic solar cells for flexible and lightweight modules. These technologies define how much clean power we can harvest per area, per kilogram, and per euro.
SweepMe! provides the backbone for photovoltaic laboratories that combine solar simulators, source measure units, spectral response equipment, motion systems, and environmental control. Instead of maintaining many small vendor tools, researchers orchestrate all measurements inside one consistent, automatable environment.
Why Photovoltaics Needs Smart Measurement Software
As record efficiencies in perovskite, silicon perovskite tandem, and organic photovoltaics approach and surpass long standing limits, careful device characterization becomes as important as materials and processing. Automated IV, SunsVoc, EQE, and stability tests turn a collection of instruments into a reliable measurement platform.
Core Technology Landscape
- Crystalline silicon solar cells as the reference for mass production and durability
- Single junction perovskite cells with steep efficiency progress and tunable bandgaps
- Silicon perovskite tandem devices that break single junction efficiency ceilings
- Organic solar cells for thin, flexible, and semi transparent modules and indoor PV
Role of SweepMe! in PV Labs
- Central control for light sources, electrical instruments, motion systems, and chambers
- Open source drivers and customizable sequences for specialized laboratory setups
- Unified data format for downstream analysis, modeling, and machine learning workflows
Photovoltaic Technologies at a Glance
Different photovoltaic technologies come with different measurement priorities. Silicon emphasizes absolute calibration and long term stability. Perovskites and organics require careful handling of hysteresis and degradation. Tandems demand junction resolved analysis and current matching.
Mature wafer based devices with sophisticated passivation and light trapping. Measurement tasks often focus on precise IV at standard test conditions, low light performance, and detailed SunsVoc and temperature dependent studies to understand recombination and series resistance.
Thin film devices with highly tunable optoelectronic properties and pronounced ionic effects. Characterization must capture forward and reverse scans, scan rate dependence, pre-conditioning, and carefully define protocols for reporting efficiency and hysteresis.
Stacked architectures that leverage a wide bandgap perovskite on top of silicon to surpass single junction limits. Junction resolved EQE, bias illumination, and current matching analysis are key, along with stability studies that track both sub cells simultaneously.
Thin-film devices with tunable absorption and mechanical flexibility. Often tested at low intensities or under indoor spectra, where accurate light level control, spectral shaping, and long term degradation tracking are crucial.
LED based solar simulator for photovoltaic testing at NASA Glenn Research Center. Image is in the public domain.
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Bring your solar simulator, monochromator and source measure unit into one workflow, from IV curves to long term stability.
IV, SunsVoc, EQE and Stability Measurements
Photovoltaic device performance is defined not by a single IV curve, but by a set of complementary measurements that probe different aspects of the device physics.
Illumination Dependent IV and SunsVoc
SweepMe! controls solar simulators or LED based light sources together with source measure units and electronic loads to perform illumination dependent IV sweeps and Maximum Power Point (MPP) tracking. SunsVoc style measurements, where voltage is recorded versus light intensity without drawing current, help to separate recombination effects from resistive losses and support device modeling.
EQE and Multi Junction Spectral Response
For spectral response measurements, SweepMe! connects monochromators or tunable light sources, choppers, lock-in amplifiers, and filter wheels. EQE can be measured with and without electrical bias voltage, and bias illumination can be added to selectively probe individual junctions in silicon perovskite tandems and other multi junction devices.
Hysteresis and Degradation Protocols
Perovskite and organic devices show time dependent behavior that must be captured in a controlled way. SweepMe! automates forward and reverse IV scans, varied scan speeds, pre bias and light soaking steps, and periodic re-characterisation during long term degradation experiments at defined temperature, humidity, and illumination levels.
Practical Challenges in PV Characterization
Modern PV devices are sensitive to illumination history, temperature, atmosphere, and device handling. Ensuring that data sets are comparable across time, across labs, and across device generations requires repeatable, automated procedures.
Time dependent phenomena, such as ion migration in perovskites or metastable states in organics, require carefully scripted timing and scan directions. SweepMe! ensures that conditioning steps and measurement sequences are applied consistently and documented.
Silicon perovskite tandems require synchronization of bias voltages, bias illumination, and EQE scans to quantify sub cell currents and losses. Coordinating all involved instruments in one SweepMe! project simplifies this complexity and lowers the risk of manual errors.
For silicon and tandem wafers or module mini arrays, motion stages and probe heads need to move across many cells or test structures. SweepMe! drives motion controllers, aligns probes, and performs recurring IV or SunsVoc measurements at every position in a predefined map.
Controlled degradation studies combine light soaking, temperature control, and defined ambient conditions with recurring performance checks. SweepMe! integrates solar simulators or light soaking setups with temperature controllers or climate chambers and automates IV, SunsVoc, and EQE measurements so that you can apply the same test protocol repeatedly over many hours or days.
Instruments and Laboratory Integration
PV laboratories typically grow over time and include equipment from many vendors. SweepMe! offers a way to integrate this heterogeneous landscape into a single control and data framework.
- Solar simulators and LED based light engines
- Monochromators and optical filter wheels for EQE and spectral response
- Shutters, attenuators, and reference detectors for intensity control
- Bias illumination channels for tandem and multi junction devices
- Source measure units and electronic loads for IV and power sweeps
- Lock in amplifiers for chopped EQE and low signal measurements
- Oscilloscopes and multimeters for transient and auxiliary channels
- Triggering and synchronization between illumination and acquisition hardware
- Linear and rotary stages for probe positioning and sample scanning
- Support for multi axis systems and probe stations
- Mapping of large area modules and combinatorial substrates
- Integration with robot arms for loading and unloading samples
- Vacuum deposition systems ( Pressure controllers and thickness monitors) for in situ characterization and process monitoring)
- Process tools for solution processing, such as spin coaters or annealing equipment
- Hotplates, ovens, and climate chambers
- Linking process steps and device measurements inside the same SweepMe! project
From Automation to Self Driving PV Labs
Many groups now explore self driving laboratories for photovoltaics, where experiment planning, device fabrication, and characterization form a closed loop with machine learning models. SweepMe! is a natural fit for the measurement and process control layer in such systems.
Autonomous materials and device acceleration platforms (AMADAP) in a photovoltaics lab. (Published by Zhang et al. in Accounts of Chemical Research, license: CC-BY 4.0
Connecting SweepMe! to Autonomous Workflows
- The tree-like SweepMe! sequencer organizes measurements as modular branches of device and logic modules, so a complete IV, SunsVoc, or EQE workflow can be saved as a reusable setting.
- Use the Condition module to react to measured values, for example by skipping branches, adjusting setpoints, or ending a run once a target condition is met.
- Via remote interfaces you can let external applications start and control SweepMe! projects, pass parameters into a running sequence, and receive measurement results while the sequencer takes care of instrument control and timing.
- Python based CustomFunction modules allow you to insert small pieces of code directly into a sequence, for example to post process data, adapt sweep ranges on the fly, or exchange summary values with an external optimizer.
Example Use Cases
- Perovskite composition screening, where an external workflow prepares a set of devices, launches a SweepMe! project for illumination dependent IV and SunsVoc characterization, and then uses the exported data to decide on the next set of recipes.
- Silicon perovskite tandem optimization, where a dedicated SweepMe! project performs EQE with bias illumination and basic stability checks, while an external script varies processing parameters and calls the same project for each new batch of samples.
- Organic PV stability studies, where SweepMe! runs long measurements with repeated IV and EQE steps under defined conditions and a separate analysis pipeline consumes the data files to train degradation models.
Frequently asked questions
Which measurements does SweepMe! cover in a PV lab?
Illumination dependent IV curves and SunsVoc, EQE and spectral response, hysteresis protocols, and long term stability and degradation runs.
Can SweepMe! control equipment from different vendors in one setup?
Yes, that is the point of the platform: solar simulators, monochromators, filter wheels, source measure units and climate chambers are combined into one control and data framework.
Is an automated or self driving PV lab possible?
Yes. Measurement sequences can be started from external workflows and the data goes into a clear file format or a database, which is the basis for autonomous experiment loops.
Get Started with Photovoltaic Characterization
Use SweepMe! to turn your photovoltaic lab into a reproducible, automatable measurement platform. From classic silicon cells to perovskite tandems and self driving workflows, one software coordinates your instruments and data.