Photoluminescence (PL) method
The solar cell or wafer is excited by a high-intensity light source. No electrical connections to the solar cell are necessary. The invisible photoluminescence radiation emitted by the wafer or solar cell is detected by a highly sensitive camera.
The photoluminescence as contactless measurement method is especially qualified for the inspection at an early stage of production and development. It enables the inspection of as-cut wafer, processed wafer and solar cells. An overview of our high-performance optical inspection systems can be found here.
Inspection of Wafer, Solar Cells & Modules
Solar cells and solar modules suffer from a variety of invisible defects which reduce their output power and long-term stability. The highly sensitive Inspection Systems from greateyes image these problems. This allows you to optimize the production, increase output power and reduce overall costs.
An external current is applied to the solar cell or module using its electrical contacts. The invisible electroluminscence radiation emitted by the solar cell or module is detected by a highly sensitive camera.
The solar cell or wafer is excited by an intensive light source. No electrical connections to the solar cell are necessary. The invisible photoluminescence radiation emitted by the wafer or solar cell is detected by a highly sensitive camera.
Advantages of Electroluminescence (EL) and Photoluminescence (PL) Inspection
- EL and PL are non-destructive methods
- Measurements deliver detailed information about defects and their location
- EL and PL provide a high informative content, many types of defects can be clearly identified
- Fast measurement on a second timescale
- EL can be used to investigate small cells as well as large areas made from mono-Si, poly-Si, a-Si, micro-Si, CIGS, CIS, CdTe
- Method can be integrated in the production process (in-line)
- EL and PL are also well suited for research and development of new photovoltaic devices
Differences between Electroluminescence (EL) and Photoluminescence (PL) Inspection
|Requirements||Electrical contacts are necessary.||No electrical contacts needed.|
|Substrates||Solar cells, strings, modules||Wafers, solar cells, as-cut wafers|
|Materials||mono-Si, poly-Si, a-Si, micro-Si, CIGS, CIS, CdTe||mono-Si, poly-Si, a-Si. micro-Si, CIGS|
|Measurement time||0.2 - 1 sec for mono-Si or poly-Si||0.2 - 2 sec for mono-Si, poly-Si|
|Informative value||Micro-cracks, shunts, finger defects, deposition problems, bad edge isolation, ...||Micro-cracks, inhomogenities, impurities, dislocations|