Solar cell performance parameters

1. Open circuit voltage
Open circuit voltage UOC: the output voltage value of the solar cell when the solar cell is placed under the AM1.5 spectral condition and the light source intensity of 100 mW/cm² is open-circuited at both ends.
2. Short circuit current
Short-circuit current ISC: It is the current value flowing through both ends of the solar cell when the output end is short-circuited when the solar cell is placed under AM1.5 spectral conditions and a light source intensity of 100 mW/cm2.
3. Maximum output power
The operating voltage and current of the solar cell vary with the load resistance, and the volt-ampere characteristic curve of the solar cell is obtained by making a curve of the operating voltage and current corresponding to different resistance values. If the selected load resistance value can maximize the product of the output voltage and current, the maximum output power can be obtained, which is represented by the symbol Pm. The working voltage and working current at this time are called the best working voltage and the best working current, which are represented by the symbols Um and Im respectively.
4. Fill factor
Another important parameter of solar cells is the fill factor FF (fill factor), which is the ratio of the maximum output power to the product of open circuit voltage and short circuit current.
FF: It is an important index to measure the output characteristics of solar cells. It is the characteristic that represents the maximum power that the solar cells can output when they are under the optimal load. The larger the value, the greater the output power of the solar cells. The value of FF is always less than 1. Series and parallel resistors have a great influence on the fill factor. The larger the series resistance, the more the short-circuit current drops, and the more the fill factor decreases; the smaller the parallel resistance, the greater the partial current, resulting in the more the open circuit voltage drops, and the more the fill factor decreases. many.
5. Conversion efficiency
The conversion efficiency of a solar cell refers to the maximum energy conversion efficiency when an optimal load resistor is connected to the external circuit, which is equal to the ratio of the output power of the solar cell to the energy incident on the surface of the solar cell. The photoelectric conversion efficiency of a solar cell is an important parameter to measure the quality and technical level of the cell. It is related to the structure, junction characteristics, material properties, operating temperature, radiation damage of radioactive particles, and environmental changes of the cell.