Mapping Non-Radiative Recombination Losses in Perovskite Solar Modules by Operando Photocurrent Spectroscopy
Beier Hu a, Artem Bakulin a
a Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, London W12 0BZ, United Kingdom
Materials for Sustainable Development Conference (MATSUS)
Proceedings of MATSUS Fall 2026 Conference (MATSUSFall26)
B4 Fundamental Understanding of Halide Perovskite Materials, Interfaces and Devices
Palma, Spain, 2026 October 26th - 30th
Organizers: Krishanu Dey and Sudipta Seth
Poster, Beier Hu, 509
Publication date: 22nd July 2026

The low-cost, solution-processable fabrication of hybrid perovskites has enabled rapid gains in power conversion efficiency and substantial improvements in the stability of perovskite solar modules, accelerating their progress towards commercialisation. Efforts to translate laboratory-scale devices to large-area modules have consequently focused on overcoming manufacturing-related limitations, including controlling active-layer crystallisation, managing laser scribing, and optimising device encapsulation. These advances have established increasingly robust fabrication strategies for module scale-up, yet the underlying electronic processes that govern non-radiative energy losses remain comparatively poorly understood. In particular, electronic traps, which mediate non-radiative trap-assisted recombination and critically undermine device performance, have yet to be systematically resolved under realistic operating conditions. Addressing this gap requires: (1) technically, a sensitive tool capable of tracking low-density trapped carriers; (2) a microscopic picture of defect physics that links local trap states to non-radiative energy losses under realistic operating conditions.

Here, we developed operando IR-modulated photocurrent spectroscopy with a spatial resolution of 50 μm to resolve both the electronic properties and spatial distribution of defects in large-area perovskite solar modules. During operation, we observed a pronounced accumulation of trapped carriers at sub-cell edges adjacent to laser-cutting interconnects, identifying these regions as localised hotspots of electronic defects. We further identified electrode degradation, manifested by a progressive reduction in photocurrent, as a distinct contributor to module degradation. These findings establish a spatially resolved picture of defects and degradation pathways at the module level, providing mechanistic insights to guide targeted optimisation of module fabrication.

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