How ISOS Protocols Are Used to Assess Perovskite Solar Cell Stability

TL; DR

ISOS protocols offer modular, research-driven guidelines for testing the stability of perovskite solar cells under realistic stress conditions like light, temperature, and electrical bias. Unlike rigid IEC tests, ISOS enables comparative studies across labs. For deeper accuracy and reproducibility, intrinsic and extrinsic stability must be tested separately using tools like LITOS or LITOS Lite. Key takeaways: don’t rely only on T80, document all conditions, and use parallel testing setups when possible.

Table of ContentsWhy ISOS Protocols MatterStandard ISOS Stability ProtocolsPurpose of Each ISOS ProtocolAdditional Protocols for PerovskitesDos and Don’ts in Stability TestingT80 and Other Figures of MeritAccelerated Aging & Arrhenius ModelsConclusion: Tools and Best PracticesReferences

Why ISOS Protocols Matter

Perovskite solar cells (PSCs) show immense promise, with rapid efficiency gains and low-cost manufacturing. However, their long-term stability under real-world conditions remains a major challenge—often overlooked in headlines focused on power conversion efficiency (PCE) records.

To address this, researchers developed the ISOS (International Summit on Organic Solar Cells Stability) protocols: a flexible framework designed to test stability under controlled stressors like heat, light, humidity, and electrical bias. Unlike IEC standards (which are geared toward silicon panels and industrial qualification), ISOS protocols are modular, open, and tailored to emerging thin-film technologies like perovskites.

This article breaks down:

• What the ISOS protocols are

• How they apply to perovskites

• How to interpret T80 and other figures of merit

• Best practices for reproducible aging tests

Whether you’re developing next-gen photovoltaics or validating long-term performance, this guide will help you align your stability tests with community standards.

The existing qualification tests of the International Electrotechnical Commission (IEC) were developed to address the field performance of silicon panels. Emerging PV technologies, like PSCs, require tests tailored to their characteristics. To standardize the stability analyses for Organic Solar Cells (OSC), a series of stressing protocols were grouped into the International Summit on Organic PV stability (ISOS). [Ree11] Likewise, it has been proposed to address the mechanisms that affect the operational stability of PSCs with protocols adapted to this specific technology.

How do we perform aging experiments that are tailored to emerging PVs? A recent Nature Energy Paper [KHEN20] published by some of the most renowned researchers on PSCs provides crucial guidelines, which will be summarized here.

This blog post provides a quick guide to understand the difference between the different ISOS protocol