---
title: Sun simulator for tandem technology
description: As solar cell prices continue to drop due to overcapacity, the demand for cost reduction in solar technology has intensified. Tandem solar cells using perovskite layers are emerging as a solution, with the potential to increase efficiency from 26% to 34%. However, accurately measuring these cells presents challenges due to hysteresis effects, particularly when using traditional XENON-based simulators. LED-based simulators, with longer and more stable flash durations, offer a solution to these issues.
---

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# [Sun simulator for tandem technology](https://pes.eu.com/digital-blog/sun-simulator-for-tandem-technology-1)

 Written by [Negin Hashemi](https://pes.eu.com/digital-blog/author/negin-hashemi) | Feb 1, 2026 1:01:08 PM

As solar cell prices continue to drop due to overcapacity, the demand for cost reduction in solar technology has intensified. Tandem solar cells using perovskite layers are emerging as a solution, with the potential to increase efficiency from 26% to 34%. However, accurately measuring these cells presents challenges due to hysteresis effects, particularly when using traditional XENON-based simulators. LED-based simulators, with longer and more stable flash durations, offer a solution to these issues.

**Why Accurate Measurement Matters** The challenge of measuring high-efficiency tandem solar cells stems from hysteresis effects, where power measurements differ depending on the direction of measurement. Key challenges include:

- **Discrepancies in power measurements** when measuring high-capacity modules, which leads to inaccurate data.
- **Short flash durations** in traditional XENON simulators exacerbate these measurement errors, particularly in production environments where cycle time is critical.

**Strategic Solutions for Measurement Accuracy** MBJ Solutions has developed advanced LED-based sun simulators to address these measurement challenges, offering the following advantages:

- **Longer Flash Durations**: LED simulators can provide flash durations of 500 milliseconds or more, necessary for accurate measurement of high-capacity tandem modules.
- **Stable Light Output**: LEDs offer long-term stability, with less than 0.5% instability over time, making them more reliable for consistent testing.

**Technology-Driven Solutions** MBJ Solutions employs several techniques to improve measurement accuracy:

- **Gradual Voltage Increase**: The system gradually increases voltage during the flash to minimize measurement discrepancies.
- **Stepwise Voltage Variation**: By varying voltage in steps during the flash, MBJ ensures accurate current stabilization, leading to more reliable Maximum Power Point (MPP) determination.
- **Improved Spectral Matching**: LEDs provide superior spectral coverage and match the solar spectrum more accurately than XENON technology, ensuring more reliable simulation results.

**The Future of Solar Cell Testing** LED-based simulators are positioned to become the standard for testing high-efficiency tandem solar cells, offering precise, stable, and scalable solutions. With advanced features like temperature control, enhanced spectral matching, and long-term stability, LED technology provides a more effective method for evaluating the performance of next-generation solar cells.

Read the full article here: https://pes.eu.com/exclusive-article/sun-simulator-for-tandem-technology/

 

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