Stereo‐hindrance Engineering of a Cation toward andlt-110andgt-‐oriented 2D Perovskite with Minimized Tilting and High‐performance X‐ray Detection
Résumé
2D <100>-oriented Dion-Jacobson or Ruddlesden-Popper perovskites are widely recognized as promising candidates for optoelectronic applications. However, the large interlayer spacing significantly hinders the carrier transport. <110>-oriented 2D perovskites naturally exhibit reduced interlayer spacings, but the tilting of metal halide octahedra is typically serious and leads to poor charge transport. Herein, a <110>-oriented 2D perovskite EPZPbBr (EPZ = 1-ethylpiperazine) with minimized tilting is designed through A-site stereo-hindrance engineering. The piperazine functional group enters the space enclosed by the three [PbBr] octahedra, pushing Pb─Br─Pb closer to a straight line (maximum Pb─Br─Pb angle ≈180°), suppressing the tilting as well as electron-phonon coupling. Meanwhile, the ethyl group is located between layers and contributes an extremely reduced effective interlayer distance (2.22 Å), further facilitating the carrier transport. As a result, EPZPbBr simultaneously demonstrates high µτ product (1.8 × 10 cm V) and large resistivity (2.17 × 10 Ω cm). The assembled X-ray detector achieves low dark current of 1.02 × 10 A cm and high sensitivity of 1240 µC Gy cm under the same bias voltage. The realized specific detectivity (ratio of sensitivity to noise current density, 1.23 × 10 µC Gy cm A) is the highest among all reported perovskite X-ray detectors.
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Xia et al_Stereo-hindrance Engineering of a Cation toward 110-oriented 2D Perovskite.pdf (1.08 Mo)
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adma202313663-sup-0001-suppmat.pdf (997.38 Ko)
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