{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T08:53:32Z","timestamp":1782377612764,"version":"3.54.5"},"reference-count":55,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,3,10]],"date-time":"2023-03-10T00:00:00Z","timestamp":1678406400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A synergistic set of NDT techniques, including I\u2013V analysis, UVF imaging, IR thermography, and EL imaging, supports a diagnostics methodology developed in this work to qualitatively and quantitatively identify a wide range of PV defects. The methodology is based on (a) the deviation of the module electrical parameters at STC from their nominal values, for which a set of mathematical expressions was developed that provide an insight into potential defects and their quantitative impact on the module electrical parameters, and (b) the variation analysis of EL images captured at a sequence of bias voltages for a qualitative investigation on the spatial distribution and strength of the defects. The synergy of these two pillars, supported by UVF imaging, IR thermography, and I\u2013V analysis cross-correlating their findings, makes the diagnostics methodology effective and reliable. It was applied on c-Si and pc-Si modules operating from 0\u201324 years, exhibiting a diversity of defects of varying severity, either pre-existing or formed by natural ageing or externally induced degradation. Defects such as EVA degradation, browning, corrosion in the busbar\/interconnect ribbons, EVA\/cell-interface delamination, pn-junction damage, e\u2212+hole recombination regions, breaks, microcracks, finger interruptions, and passivation issues are detected. Degradation factors triggering a cascade of internal degradation processes through cause and effect are analysed and additional models are proposed for the temperature pattern under current mismatch and corrosion along the busbar, further empowering the cross-correlation of NDT results. Power degradation was determined from 1.2% in 2 years of operation to more than 50% in modules with film deposition.<\/jats:p>","DOI":"10.3390\/s23063016","type":"journal-article","created":{"date-parts":[[2023,3,13]],"date-time":"2023-03-13T03:28:33Z","timestamp":1678678113000},"page":"3016","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["PV Defects Identification through a Synergistic Set of Non-Destructive Testing (NDT) Techniques"],"prefix":"10.3390","volume":"23","author":[{"given":"Socrates","family":"Kaplanis","sequence":"first","affiliation":[{"name":"Renewable Energy Systems Lab, University of Peloponnese, 26334 Patra, Greece"},{"name":"Lab of Soft Energy Applications and Environmental Protection, University of West Attica, 12201 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4987-4388","authenticated-orcid":false,"given":"Eleni","family":"Kaplani","sequence":"additional","affiliation":[{"name":"School of Engineering, Faculty of Science, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2255-7427","authenticated-orcid":false,"given":"Paul Nicolae","family":"Borza","sequence":"additional","affiliation":[{"name":"Department of Electronics & Computers, Transilvania University of Brasov, 500036 Brasov, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Khan, F., and Kim, J.H. 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