Pressure‐Induced Structural and Optoelectronic Modulations in 2D Dion‐Jacobson Hybrid Lead Iodide Perovskites With a Rigid Spacer
Bibliographic record
Abstract
Abstract 2D hybrid organic‐inorganic perovskites (HOIPs) are known for their superior chemical and thermal stability over 3D variants, positioning them as promising materials for advanced optoelectronic applications. Applying external high pressure is an effective strategy to modify their structures and tune their optoelectronic properties. This study examines the high‐pressure behavior of a Dion‐Jacobson type 2D HOIP, DPDAPbI4, which incorporates the rigid organic spacer N,N‐dimethylphenylene‐p‐diammonium (DPDA). Utilizing photoluminescence, UV–visible absorption, vibrational spectroscopy, and in situ synchrotron powder X‐ray diffraction, an isostructural phase transition is identified near 1.5 GPa, marked by a notable shift in photoluminescence intensity linked to free exciton emission. Synchrotron X‐ray diffraction reveals significant anisotropic compression along the c‐axis, while structural analysis indicates the rare phenomenon of reduced lead‐iodide octahedral distortion below 2 GPa, contrasting with the increased octahedral distortion reported in most previous studies on lead‐based 2D HOIPs. Density functional theory calculations elucidate the structural origins and mechanisms driving the pressure‐induced phase transition and optoelectronic tuning. These findings underscore the critical interplay between rigid organic spacers and inorganic octahedra in modulating high‐pressure optoelectronic properties, offering valuable insights for designing future 2D HOIPs with tailored functionalities.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".