{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T13:30:59Z","timestamp":1787923859095,"version":"build-2784847793"},"reference-count":42,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T00:00:00Z","timestamp":1787875200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["RS-2023-00208792"],"award-info":[{"award-number":["RS-2023-00208792"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"award":["RS-2023-00208792"],"award-info":[{"award-number":["RS-2023-00208792"]}],"id":[{"id":"https:\/\/ror.org\/013aysd81","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003662","name":"Korea Evaluation Institute of Industrial Technology","doi-asserted-by":"publisher","award":["RS-2023-KT226765"],"award-info":[{"award-number":["RS-2023-KT226765"]}],"id":[{"id":"10.13039\/501100003662","id-type":"DOI","asserted-by":"publisher"}]},{"award":["RS-2023-KT226765"],"award-info":[{"award-number":["RS-2023-KT226765"]}],"id":[{"id":"https:\/\/ror.org\/03z9cwa38","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nanomaterials"],"abstract":"<jats:p>Organic\u2013inorganic hybrid perovskites (OHPs) deliver certified single-junction power conversion efficiencies (PCEs) of up to 27.3% and National Laboratory of the Rockies (NLR)-certified perovskite\u2013silicon tandem values of 34.85%, yet a substantial gap with the Shockley\u2013Queisser (S\u2013Q) limit persists. Grain-boundary (GB) defects are one principal contributor to this gap, driving non-radiative recombination, ion migration, and degradation alongside bulk, interfacial, contact-related, phase-related, and environmental loss channels. Rational passivation demands a non-contact tool capable of identifying and quantifying specific defect species in device-relevant thin films, a capability that conventional probes deliver only in part. This overview assesses the extent to which terahertz time-domain spectroscopy (THz-TDS, 0.2\u20132.5 THz) fulfills this role. Across five OHP compositions\u2014MAPbI3, MAPbBr3, FAPbI3, and FAPb(Br,I)3 fabricated by sequential vacuum evaporation (SVE), together with solution-processed \u03b3-CsPbI3\u2014the THz spectral window captures both intrinsic phonon modes and GB-localized molecular defect vibrations, enabling species-resolved characterization at room temperature. Notably, the oscillator strength of the SVE-specific 1.58 THz absorption in MAPbI3 scales linearly with XPS-quantified CH3NH2 defect concentration, establishing a calibrated, contact-free proxy for defect concentration rather than an absolute defect count; the observable is the defect-induced perturbation of the Pb\u2013X lattice, not the defect population itself. Building on these findings, we propose a three-pillar framework for THz-guided defect engineering: (I) quantitative defect measurement via oscillator-strength analysis, (II) material-specific fingerprint identification from a systematically constructed THz library, and (III) fingerprint-guided defect elimination with real-time feedback\u2014together defining a closed-loop quality-control cycle that connects spectroscopic diagnosis to passivation strategy and, ultimately, to enhanced solar cell efficiency. Throughout, we distinguish capabilities demonstrated to date from extensions that remain proposals, and we define the measurement requirements needed before the framework can be transferred to inline manufacturing control.<\/jats:p>","DOI":"10.3390\/nano16171072","type":"journal-article","created":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T12:27:46Z","timestamp":1787920066000},"page":"1072","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Terahertz Time-Domain Spectroscopy as a Defect Fingerprinting Tool for Halide Perovskite Solar Cells: Toward a Universal Framework"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7499-8588","authenticated-orcid":false,"given":"Inhee","family":"Maeng","sequence":"first","affiliation":[{"name":"YUHS-KRIBB Medical Convergence Research Institute, College of Medicine, Yonsei University, Seoul 03722, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Young Mi","family":"Lee","sequence":"additional","affiliation":[{"name":"Beamline Division, Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 37673, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jinwoo","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Seoul, Seoul 02504, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seung Jae","family":"Oh","sequence":"additional","affiliation":[{"name":"YUHS-KRIBB Medical Convergence Research Institute, College of Medicine, Yonsei University, Seoul 03722, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6073-0908","authenticated-orcid":false,"given":"Min-Cherl","family":"Jung","sequence":"additional","affiliation":[{"name":"Global Institute of Future Technology, Shanghai Jiao Tong University, Shanghai 200240, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Suchikova, Y., Nazarovets, S., Konuhova, M., and Popov, A.I. 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