Tailoring Potential Ferroelectric Properties in Conformationally Switchable Er(III)-Isothiocyanates Using Organic Cation Modulation
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Hybrid molecular ferroelectrics necessitate switchable components, either organic or inorganic, capable of altering polarity under a reversing electric field. Isothiocyanate (NCS – ) ligands display such behavior through nonlinear coordination with metal ions. Homoleptic complexes of lanthanide ions exhibit variable coordination numbers, which can be controlled by the size of the counterions. We harnessed these properties to achieve polar order and ferroelectricity in hybrid [Er(III)(NCS) x ] 3-x complexes. The incorporation of triethyl methylammonium ( TEMA ) cations yields the complex [TEMA] 4 [Er(NCS) 7 ], which exhibits polarity at low temperatures with a Curie temperature ( T c ) of 203 K. Notably, the use of bulkier and more rigid ethyltriphenyl phosphonium ( ETPP ) cations gave a room-temperature stable ferroelectric complex [ETPP] 3 [Er(NCS) 6 ] . In contrast, flexible cations, such as tripropylmethylammonium ( TPMA ), tributylmethylammonium ( TBMA ), and tetraethyl phosphonium ( TEP ) ions, yielded only centrosymmetric complexes. The polar structural symmetries in [TEMA] 4 [Er(NCS) 7 ] and [ETPP] 3 [Er(NCS) 6 ] are attributed to pronounced distortions of the Er(III)-NCS coordination, driven by the rigid nature of organic counterions. The ferroelectric measurements on [ETPP] 3 [Er(NCS) 6 ] gave a saturation polarization ( P s ) of 1.6 μC cm –2 . Remarkably, [ETPP] 3 [Er(NCS) 6 ] exhibits a high piezoelectric charge coefficient ( d 33 ) of 22.7 pCN –1 and an electrostrictive coefficient ( Q 33 ) of 4.11 m 4 C –2, enabling its application for piezoelectric energy harvesting.
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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".