Fraud-screening report: 'Stable Hard X-ray Detectors by High-Charge-Mobility Two-Dimensional Cu(Gly)₂Pb₂Br₄ Single Crystal' (DOI: 10.1021/acsenergylett.4c02866)

Academic fraud report · Geng Detector

Summary

Verdict: Highly suspicious (orange/red flags). The Geng-style screening report, based solely on the text of the paper and the authors' extracted data, raises four principal concerns. (1) The reported optical bandgap of 0.99 eV (absorption edge ~1169 nm) for a pure Pb–Br perovskite-type phase is incompatible with established solid-state chemistry, where MAPbBr₃ and analogues sit at 2.2–3.0 eV; a sub-1 eV gap would imply near-infrared absorption that no known bromide perovskite exhibits. (2) The claimed out-of-plane hole mobility of 54.1 cm² V⁻¹ s⁻¹ and trap density of 1.09×10¹⁰ cm⁻³ for a 2D material exceed even high-quality 3D single-crystal perovskites, raising fabrication plausibility questions. (3) The reported dark-current drift of 4.93×10⁻¹⁸ A cm⁻¹ V⁻¹ s⁻¹ is below the noise floor (10⁻¹⁵–10⁻¹⁶ A) of common semiconductor parameter analysers. (4) Severe text-extraction artefacts in equations and affiliations hint at possible post-production image/PDF splicing. Confidence is moderate because original high-resolution figures and raw data were not examined.

Verdict

Highly suspicious. Four mutually reinforcing anomalies span claimed physical parameters, device performance metrics, and document integrity signals. A formal investigation is warranted, but final determination requires inspection of original UV-vis raw spectra, Tauc-plot fitting, SCLC curves, dark-current measurement setup, and original figure files.

Key findings

Implausible optical bandgap for a pure Pb–Br system: the paper reports an absorption edge at ~1169 nm, corresponding to a Tauc-derived bandgap of 0.99 eV. Reference Pb–Br perovskites (e.g., MAPbBr₃) typically have bandgaps in the 2.2–3.0 eV range. A 0.99 eV gap in a pure bromide framework is inconsistent with known solid-state chemistry.
Unrealistic charge-transport figures for a 2D perovskite: out-of-plane hole mobility is reported as 54.1 cm² V⁻¹ s⁻¹ with a trap-state density of 1.09×10¹⁰ cm⁻³, both far above typical values for 2D perovskites and competitive with state-of-the-art 3D single crystals and high-temperature-annealed silicon.
Dark-current drift below instrument noise floor: 4.93×10⁻¹⁸ A cm⁻¹ V⁻¹ s⁻¹ is several orders of magnitude below the ~10⁻¹⁵–10⁻¹⁶ A background of standard semiconductor parameter analysers (e.g., Keithley 2400/4200 series), without disclosure of extraordinary shielding or cryogenic conditions.
Document-integrity red flags: equations and affiliations extracted with anomalous character fragmentation (e.g., W E2 1.43 e V g = + ±, J V L 9 8 D 0 2 3 =, affiliations rendered as sı and CiteThis:ACSEnergyLett), consistent with post-hoc PDF/image editing rather than native typesetting.

Evidence highlights

Reported bandgap 0.99 eV vs. expected 2.2–3.0 eV for Pb–Br perovskites (Introduction, Fig. 1h description).
Mobility 54.1 cm² V⁻¹ s⁻¹ and trap density 1.09×10¹⁰ cm⁻³ (Fig. 2c and 2e descriptions).
Dark-current drift 4.93×10⁻¹⁸ A cm⁻¹ V⁻¹ s⁻¹ (Fig. 3c description).
Extracted text artefacts in equations (1) and (4) and in author affiliations.
DOI of the original paper: 10.1021/acsenergylett.4c02866.
Authors as listed: Jinghui Han, Weijun Li, Jinmei Song, Mingbian Li, Yuhong He, Wei Wei, Bai Yang, and Haotong Wei. Published online 16 December 2024 in *ACS Energy Letters*.

Notes

This screening is text-based only; original high-resolution images and raw data were not examined by the detector.
Some anomalies (notably the text-extraction artefacts) could in principle reflect a poorly generated PDF rather than deliberate manipulation, but their co-occurrence with the physical-data anomalies raises the overall concern level.
Recommended follow-up: request raw UV-vis transmittance and Tauc-plot derivation; check SCLC fitting constraints; verify instrument model, shielding, and environment for the dark-current measurement; raise the concerns via PubPeer and notify the journal editorial office. No findings here constitute a formal finding of misconduct.