Ultraviolet Fluorescence

UVF Imaging
For the Field

High-throughput UVF systems for fast, non-contact inspection of PV panels.

The UVF-Spot pole mounted camera system has revealed a wide range of defects across many different panel types that were not visible using other techniques. The system is easy to use and doesn't require touching the MC4 cables. BrightSpot was very supportive in helping to interpret the UVF defect images and educating our team.

Dr. Amir Abdallah,
Qatar Environment and Energy Research Institute (QEERI)

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Fast Non-Contact Imaging

Where It Works, It Works Great; UVF works best on panels with polymer backsheets that have been in the field already for a few years. As the encapsulant ages, its fluorescence image evolves, revealing some defects even more clearly than EL.

Ultraviolet Fluorescence (UVF)

Detect PID, encapsulant degradation, and other age-related or environmental damage, especially useful for performance monitoring and field inspection of aging installations.

How UVF compares to EL and PL

See what UVF can do compared to Electroluminescence and Photoluminescence

Factor EL PL UVF
Noncontact – no need to bias cells/panels Yes No No
High Throughput No No Yes
New Panels Yes Yes No
See cracks Yes Yes Yes
See disconnected cell segments Yes No No
Tell “when” cracking happened No Yes No
See cold solder or weld joints Yes No No
See gridline corrosion Yes Yes Yes
See hot spots No No Yes
See edge seal and junction box seal failure No No Yes

UVF can reveal a wide range of panel problems and non-uniformities

The UV Fluorescence technique works with panels that have polymer backsheets. Fluorophores are contained in panel encapsulants and backsheets – leading to fluorescence in the visible spectrum when exposed to UV light.

Encapsulant BOM Variations

Backsheet BOM Variations

Gridline
Corrosion

Edge Seal Failure

Non-uniform Lamination

Cell Cracking
Dating

Hotspots and Yellowing

J-Box Seal Failure

decades of experience and hundreds of customers

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Our Latest Publications

The latest publications and technical outputs from BrightSpot Automation

Ultraviolet Fluorescence Imaging for Photovoltaic Module Metrology: Best Practices and Survey of Features Observed in Fielded Modules

IEEE Journal of Photovoltaics ( Volume: 15, Issue: 3, May 2025)

Low-Cost Daytime Electroluminescence Imaging

NREL PV Reliability Workshop – Lakewood, CO USA – Mar 6, 2025

UV Fluorescence Imaging for Solar Panel Product Development and Durability Testing

NREL PV Reliability Workshop – Lakewood, CO USA – Feb 28, 2024

Unveiling the Unseen: Harnessing UV Fluorescence for Comprehensive Rooftop PV System Assessment and Successful Insurance Claims Process

NREL PV Reliability Workshop – Lakewood, CO USA – Feb 28, 2024

Detection and Impact of Cracks Hidden Near Interconnect Wires in Silicon Solar Cells

50th IEEE PVSC, Jun 12 2023

UV Fluorescence for Detection of Solar Panel Bill of Materials Variations

2023 NREL PV Reliability Workshop, Feb 28, 2023