Compositionally disordered perovskite compounds have been one of the exotic topics of research during the past several years. Colossal piezoelectric and electrostrictive effects have been observed in disordered perovskite ferroelectric materials. The key ingredient in the physical behavior of disordered perovskites is the nucleation and growth of the local dipolar regions called polar nanoregions (PNRs). PNRs begin to nucleate far above the temperature of the dielectric maximum and exhibit varied relaxation behavior with temperature. The evidence for the existence of various stages in the relaxation dynamics of PNRs was revealed through the study of the temperature evolution of optical phonons by Raman scattering. The quasi-static regime of PNRs is characterized by the strong coupling between the local polarization and strain with the local structural phase transition and the critical slowing of the relaxation time. Strong anomalies in the frequency and the width of the acoustic phonons, and emergence of the central peak in the quasi-static region of the relaxation dynamics of PNRs have been observed through Brillouin scattering studies. In this review, we discuss the anomalies observed in Brillouin scattering in selected disordered perovskite ferroelectrics crystals such as Pb(MgTa)O Pb(ScTa)O, 0.65PIN-0.35PT and SrCaTiO to understand dynamical behavior of PNRs.
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http://dx.doi.org/10.3390/ma16020605 | DOI Listing |
Adv Mater
January 2025
Institute for Advanced Materials & Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China.
Laboratory-scale spin-coating techniques are widely employed for fabricating small-size, high-efficiency perovskite solar cells. However, achieving large-area, high-uniformity perovskite films and thus high-efficiency solar cell devices remain challenging due to the complex fluid dynamics and drying behaviors of perovskite precursor solutions during large-area fabrication processes. In this work, a high-quality, pinhole-free, large-area FAPbI perovskite film is successfully obtained via scalable blade-coating technology, assisted by a novel bidirectional Marangoni convection strategy.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
-site cation ordering in double perovskites is crucially important for their physical properties. In this study, polycrystalline samples of Zr-based double perovskite NaLaZrO were synthesized via high-temperature solid-state reactions, and the influence of the heating temperature and cooling rate on their crystal structures was investigated using synchrotron X-ray diffractometry and optical second harmonic generation. The samples prepared at 1200 °C, followed by slow cooling to room temperature, crystallize in a polar 2 structure, exhibiting partial -site cation ordering, with Na- and La-rich -site layers alternately stacked along the axis.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Group of Characterization of Materials, Departament de Física, Universitat Politècnica de Catalunya, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, Barcelona 08019, Spain.
Hybrid organic-inorganic perovskites (HOIP) have emerged in recent years as highly promising semiconducting materials for a wide range of optoelectronic and energy applications. Nevertheless, the rotational dynamics of the organic components and many-molecule interdependencies, which may strongly impact the functional properties of HOIP, are not yet fully understood. In this study, we quantitatively analyze the orientational disorder and molecular correlations in archetypal perovskite CHNHPbI (MAPI) by performing comprehensive molecular dynamics simulations and entropy calculations.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Materials Physics Center, CSIC-UPV/EHU, Paseo de Manuel Lardizabal, 5, 20018 Donostia - San Sebastian, Spain.
Hybrid perovskites exhibit complex structures and phase behavior under different thermodynamic conditions and chemical environments, the understanding of which continues to be pivotally important for tailoring their properties toward improved operational stability. To this end, we present for the first time a comprehensive neutron and synchrotron diffraction investigation over the pressure-temperature phase diagram of the paradigmatic hybrid organic-inorganic perovskite methylammonium lead iodide (MAPbI). This ambitious experimental campaign down to cryogenic temperatures and tens of kilobars was supported by extensive molecular dynamics simulations validated by the experimental data, to track the structural evolution of MAPbI under external physical stimuli at the atomic and molecular levels.
View Article and Find Full Text PDFSmall
December 2024
Institute of Polymer Optoelectronic Materials & Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology, Guangzhou, 510640, China.
Polymer hole transport materials offer significant efficiency and stability advantages for p-i-n perovskite solar cells. However, the energetic disorder of amorphous polymer hole transport materials not only limits carrier transport but also impedes contact between the polymer and perovskite, hindering the formation of high crystalline quality perovskites. Herein, a novel low energetic disordered polymer hole transport material, PF8ICz, featuring an indeno[3,2-b]carbazole unit with extended π-conjugation is designed and synthesized.
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