Application of high-precision source meter in solar cell characteristic test

With the rapid development of the world economy and the deepening of industrialization, human demand for energy is increasing day by day. Compared with non-renewable fossil fuel energy, solar radiation can maintain a constant output for tens of billions of years, and the conversion of light energy into electrical energy is an extremely important process. Solar cells are a type of photoelectric semiconductor sheet that uses sunlight to generate electricity directly. When the illumination meets certain conditions, it can instantly output voltage and generate current in the presence of a circuit. It is widely used in various fields such as transportation, communications, and satellites.

From research and development to production, solar cells have different testing requirements in each link. Their photoelectric characteristics include volt-ampere I-V characteristics, spectral response SR characteristics, and quantum efficiency QE characteristics. Among them, I-V characteristic analysis is crucial to deriving important parameters related to solar cell performance, mainly including maximum current I-max and voltage V-max, open circuit voltage Voc, short circuit current Isc, fill factor ff, and conversion efficiency η. In order to accurately complete the I-V characteristic test of solar cells, the tester needs to use a solar simulator light source to irradiate the sample within a certain distance, and then use precision electrical instruments to measure the I-V characteristic curve to obtain the battery parameters.

When there is no light, the specified DC bias voltage is required to measure the IV characteristics of solar cells, and the IV characteristic curve under forward bias voltage is measured; when there is no bias voltage, the IV characteristics of solar cells under different load conditions are measured by incident light of various wavelengths (the load characteristics of multiple series are more obvious), and the short-circuit current Isc, open-circuit voltage Voc, maximum power, optimal operating current and voltage are measured. The NGI N2600 series high-precision digital source meter integrates source-measurement functions, can output ultra-high-precision voltage source and current source, and provides measurement functions, which can fully meet the needs of solar cell IV characteristic testing.

Spectral response SR is an indicator for evaluating the photoelectric conversion capability of solar cells. Provide incident light of various wavelengths, and the ratio of the current converted after receiving the incident light to the incident light energy is the spectral response SR. The N2600 series source meter can accurately measure the photocurrent to complete the SR current characteristic test.

Generally, power supplies only provide 1st and 3rd quadrant operation, emitting energy as a source. The N2600 series can provide full four-quadrant operation. When working in the 2nd and 4th quadrants, it can absorb energy as a sink (load). In source or sink mode, it can measure voltage, current and resistance. Its maximum sampling speed can reach 100ksps, and the scanning speed is 1ms per point.