Quantum Efficiency Measurement System is a key tool for evaluating photovoltaic cell performance, especially for complex perovskite/Si tandem solar cells. The device ensures measurement accuracy and repeatability through high-precision light sources and advanced signal processing technology. The Quantum Efficiency Measurement System can simulate natural spectra, adapt to different research needs, and provide accurate quantum efficiency values, making it an ideal choice for research and industrial applications.

Working Principle of Quantum Efficiency Measurement System

Quantum efficiency (QE) is an important parameter to measure the response of solar cells to incident light, which reflects the photoelectric conversion capability of solar cells. Quantum efficiency is defined as the ratio of the number of collected charge carriers to the number of incident photons. In the research and application of solar cells, improving quantum efficiency is the key to improving photoelectric conversion efficiency.

Sigmoid wavelength and energy range of QE spectrum absorption threshold

Quantum Efficiency Measurement System is a device used to measure the photoelectric conversion efficiency of a photodetector at a specific wavelength. During the operation of the quantum efficiency tester, the monochromator decomposes the white light from the light source into monochromatic lights with different wavelengths. These monochromatic lights are then converted into pulsed lights by a chopper. When these pulsed monochromatic lights of different wavelengths are irradiated onto the solar cell sample, the cell will generate corresponding pulsed photocurrents. Next, a lock-in amplifier is used to receive and amplify these weak pulsed photocurrent signals. In order to make accurate measurements, it is also necessary to test the pulsed photocurrent signal generated by a standard solar cell with a known quantum efficiency value. By comparing these two signals, we can accurately calculate the quantum efficiency value of the sample to be tested. This method not only improves the signal-to-noise ratio of the signal, but also ensures the accuracy and repeatability of the measurement.

Working principle diagram

Quantum Efficiency Measurement System Application in Perovskite/Si tandem Cell

Due to the structural characteristics of perovskite/Si tandem cells, their QE test needs to be performed separately, that is, irradiate a bias light, turn on one of them to make it a conductor, and test the other one.

Control of lighting conditions: According to the research on silicon-based perovskite tandem solar cells, the device efficiency can be effectively improved through reasonable light absorption distribution and light management strategies. Therefore, when conducting quantum efficiency testing, it should be ensured that the light source can evenly cover the entire test area and can simulate the natural spectrum or other specific spectrum to meet different research needs.

Top perovskite measurement:

When the top is illuminated, an 850nm long-pass filter is used to adjust the optimal bias light intensity. When the bias light intensity is weak, the photogenerated carriers generated are not enough to fill the traps, and the measured value is small.

When the bias light intensity is large, the accumulation of photogenerated carriers causes the electron diffusion coefficient in the P region to increase, the saturation current density to increase, and the measured EQE is smaller than the actual value.

Bottom silicon measurement:

With 550nm short-pass filter, light is received at the top, and the optimal bias light intensity is adjusted

Because the carriers are transferred from the top junction to the bottom junction, the top perovskite will have a photogenerated voltage under light, which hinders the current of the Si junction. Therefore, a bias voltage must be added at both ends of the voltage. During the test, the bias voltage must be gradually changed to find the optimal bias voltage point.

Quantum Efficiency Measurement System

E-mail: market@millennialsolar.com

Compatible with all types of photovoltaic cells

Four-junction cell test (polarization/bias mode)

EQE measurement repeatability:

Small spot: 300nm-400nm＜0.5%; 400nm-1800nm＜0.25%

Large spot: 300nm-400nm, 1000nm-1800nm＜1%, 400nm-1000nm ＜0.5%;

Reflectivity repeatability: (small spot): 300nm-400nm＜0.5%, 400nm-1800nm＜0.25%

Short-circuit current density repeatability: ＜0.1%

Optical stability ≤0.2% @550nm

Quantum Efficiency Measurement System plays an indispensable role in the performance evaluation of photovoltaic cells. By accurately simulating the natural spectrum and utilizing advanced optoelectronic technology, the device not only provides highly accurate test results, but also adapts to various complex cell structures. With the rapid development of photovoltaic technology, Quantum Efficiency Measurement System will continue to provide reliable support for research and industry, and help the continuous improvement of solar cell efficiency and technological innovation.