Principle

The basis of the working principle of solar cells is the photovoltaic effect of the semiconductor PN junction. Photovoltaic effect is when the object is illuminated, the charge distribution state in the object changes to produce electromotive force and current. When sunlight or other light irradiates the PN junction of the semiconductor, a voltage appears on both sides of the PN junction, which is called photo-generated voltage. When light is irradiated on the PN junction, electron-hole pairs are generated. The carriers generated near the PN junction inside the semiconductor are not recombined and reach the space charge zone. Attracted by the internal electric field, electrons flow into the N zone, and holes Flow into the P area, resulting in excess electrons stored in the N area, and excess holes in the P area. They form a photogenerated electric field that is opposite to the direction of the barrier near the P-N junction. In addition to partially offsetting the effect of the barrier electric field, the photogenerated electric field also makes the P zone positively charged and the N zone negatively charged. An electromotive force is generated in the thin layer between the N zone and the P zone. This is the photovoltaic effect.

Overview

In this experiment, the iodine tungsten lamp simulates sunlight, irradiates the solar panel to generate electricity,   and then measure the irradiance of sunlight at different positions with a spectroradiometer to measure the output characteristics of the solar cell (Three samples of monocrystalline silicon, polycrystalline silicon and amorphous silicon) under light and obtain its short-circuit current (I_SC), open circuit voltage (U_OC), maximum output power P_max and fill factor FF. FF is an important parameter representing the performance of solar cells.

Features

• Adopt the building block design, students can change different solar cell sample components by themselves, and train students' experimental construction and hands-on ability;

• This experiment contains a spectroradiometer, which can easily measure the intensity of sunlight.

• This experiment contains three types of solar cell modules: monocrystalline silicon, polycrystalline silicon and amorphous silicon. The experiment is rich in content, and the experiment process is environmentally friendly and clean.

• Convenient data collection interface: The experimental power supply is equipped with 3 analog data collection interfaces, which can be connected to voltage sensors and PASCO data collection software, which can collect a large amount of data in real time to analyze the test results, and complete the experiment content conveniently, quickly and efficiently.

Experiments and Data

The voltage-current characteristic of the applied voltage of the solar cell under full dark conditions

Measure the open circuit output voltage U_OC and short circuit current I_SC of solar cells under different light intensities

Measurement experiment of solar cell output characteristics under light

Parts List

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