Breakthroughs in Stability: Key Takeaways from ISOS 16

Over three days of technical presentations and open discussions, one thing was clear: the path to commercial viability for perovskite and organic photovoltaics (PSC and OPV) runs through deep understanding, smart design, and rigorous testing for long-term reliability.

This recap offers a structured overview of the most relevant breakthroughs shared at ISOS 16. Whether you’re revisiting a session, catching up on what you missed, or looking ahead to ISOS 17, this overview captures the current state-of-the-art in photovoltaic stability research.

Real-World Durability: From Earth to Orbit

Encapsulation and outdoor degradation were core themes at ISOS 16, with notable progress across both OPV and PSC technologies. Y-series non-fullerene acceptors (NFAs) with fluorinated end-groups demonstrated promising thermal and outdoor stability of OPV devices. However, interfacial degradation remains a critical issue, with HTL materials such as 2PACz showing decomposition over time.

Breakthroughs in large-area perovskite modules were particularly notable. Stable 0.8 m² modules reached 15% PCE, and UV ageing models predicted an outdoor lifetime of approximately two years based on 60 kWh/m² exposure. Flexible PSCs for space applications were also discussed, with recent tests indicating resilience to neutron irradiation — an essential requirement for low Earth orbit (LEO) satellite missions.

At the system level, outdoor testing platforms helped differentiate performance trends between OPV and PSC technologies. Notably, perovskites exhibited positive temperature coefficients under field conditions. Additionally, new portable and low-cost OPV testing systems were introduced, enabling real-time, real-world performance logging, which indicates a practical step forward for wider deployment.

Degradation Mechanisms: Mapping the Failure Modes

Multiple sessions shed light on the physical origins of device degradation. Among the key findings: copper corrosion, phase segregation, and laser-induced edge effects emerged as recurring challenges for PSCs. The use of self-assembled monolayers (SAMs) improved initial performance, but spacer deterioration limited long-term operation.

Novel imaging methods and testing techniques revealed further insights. Temperature-dependent degradation and recovery dynamics were tracked via photoluminescence (PL) imaging, revealing the metastable nature of several device configurations. Proton-induced damage, another crucial factor for satellite-bound PV, was shown to be reversible via thermal annealing.

In high-performance OPV systems, donor–acceptor combinations demonstrated varying photodegradation behaviours under filtered light, and polymer backbones with specific fluorination patterns showed markedly improved photostability. Reverse bias and shading studies confirmed that silver electrodes remain particularly vulnerable to shunting — a significant concern for module reliability.

Predictive Modelling & AI: Smarter Screening, Better Design

AI and modelling continue to shape next-generation PV development. ISOS 16 featured several contributions using Bayesian optimisation to efficiently screen materials and predict device performance. These methods accelerate discovery cycles while reducing experimental load.

Beyond pure AI, hybrid models that couple machine learning with physical modelling are now being used to identify degradation pathways. These approaches integrate ISOS protocol datasets to simulate long-term behaviour and assist in standardising interpretation of test results. This direction holds great promise for harmonising research efforts across labs and continents.

Towards Industrial Scale-Up: Bigger, Better, More Reliable

Perovskite stability research is no longer limited to lab-scale devices. Several studies presented at ISOS 16 showcased progress in scaling up device size while maintaining performance. Notably, modules with dimensions up to 1200 × 650 mm² reached efficiencies as high as 19.7%.

Industrial-scale interface engineering emerged as a critical factor. From buffer layer optimisation to improved top contact materials, each layer’s contribution to stability was quantified. Slot-die coated inverted devices showed superior resilience, especially at the HTL/Ag interface.

Encapsulation techniques also received renewed focus, particularly for mitigating edge-related degradation caused by laser scribing or silver grid diffusion. These solutions are helping bridge the gap between high-efficiency lab results and long-term reliability in real-world applications.

Low-Power & Indoor PV: Broadening the Application Space

Not all PV applications demand harsh outdoor exposure. For indoor and low-light environments, OPV devices are uniquely suited. Transparent indoor OPVs with 12.5% PCE and long-term stability were presented, alongside proposed standards for indoor PV testing under controlled lighting (e.g. 5000K LED, 200 lux).

Interface materials again played a key role. Organophosphorus-based interlayers were shown to extend device lifetimes even without encapsulation, opening doors to lighter, thinner, and more flexible product designs.

Shared Insight for Shared Progress

Beyond the technical breakthroughs, ISOS 16 underscored the growing maturity of the PV stability field. The introduction of the ISOS Stability Competition — benchmarking the most robust devices across labs — reflects a community-wide commitment to transparency and replicability. Discussions on FAIR data principles and inline characterisation highlighted the need for standardised, sharable datasets to accelerate collective progress.

The collaborative spirit that defines ISOS was palpable throughout the sessions, posters, and informal discussions. As the field shifts from efficiency races to lifecycle validation, the importance of stability-first thinking is now universally acknowledged.

ISOS 16 brought together the people, tools, and perspectives needed to build not just better devices, but a more stable solar future.

This recap was compiled based on session summaries provided by the ISOS 16 committee. For more information, speaker lists and event photos, visit the ISOS 16 event page.