cs.AIOct 31, 2026

Evidence-grounded large language models guide perovskite solar cell design and optimization

Authors: YanKai Chen, Zhi Wan, ZiHao Li, Tao Jing

Organizations: School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China. · College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science & Technology, Xi’an 710021, P. R. China. · Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China.

Abstract

Using large language models to interpret experimental evidence, design discriminating experiments and formulate well-supported mechanistic explanations remains a central challenge in materials research. Here we establish PSM-Bench, an 800-question benchmark developed by perovskite researchers to evaluate scientific reasoning in perovskite photovoltaics. We also introduce OpenPerov, an expert-informed language-model framework that learns from expert-calibrated evidence records reconstructed from 4,035 training articles; these records link experimental strategies, controls and observations to mechanistic interpretations. Structured-evidence adaptation outperformed conventional question-answer training, and OpenPerov Flash ranked first among 13 closed-book systems. OpenPerov Pro raised Scientific Mastery further, from 87.6 to 89.1, by revising selected passages with retrieved evidence. On questions derived from subsequent studies, both models also outscored expert-authored answers. In an experimental test of self-assembled monolayer design, OpenPerov selected a K analogue that outperformed the Na analogue preferred by experts. Devices incorporating the selected contact reached a power conversion efficiency of 27.05% and retained 96.74% of their initial efficiency after 1,000 h of dark thermal ageing at 85 ∘^\circC. These results show that reconstructed scientific reasoning provides an effective basis for building domain models that interpret experiments and inform materials design.

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