000162998 001__ 162998
000162998 005__ 20251009133841.0
000162998 0247_ $$2doi$$a10.1039/d5cp02842f
000162998 0248_ $$2sideral$$a145478
000162998 037__ $$aART-2025-145478
000162998 041__ $$aeng
000162998 100__ $$0(orcid)0000-0002-5999-341X$$aArauzo, Ana$$uUniversidad de Zaragoza
000162998 245__ $$aLow-energy modes and localized excitations in metal halide perovskites: insights from heat capacity
000162998 260__ $$c2025
000162998 5060_ $$aAccess copy available to the general public$$fUnrestricted
000162998 5203_ $$aMetal halide perovskites (MHPs) hold great potential to integrate future mass-produced photovoltaic technologies owing to their exceptional power conversion efficiencies and charge-carrier transport properties. However, their performance is still hindered by a poor understanding of their complex soft structures and the role played by defects and impurities in their optoelectronic properties. For the first time, the molar heat capacities of two archetypal MHPs – MAPbI3 and FAPbI3 – as well as two thermodynamically stable non-perovskite specimens δ-FAPbI3 and δ-CsPbI3 have been measured down to 0.35 K. The behavior of the four crystals below 10 K departs notably from the predictions of the Debye model. All samples exhibit a broad feature in the Debye-reduced C/T3 representation that can be interpreted from harmonic lattice dynamics calculations as the excitation of low-energy optical vibrations. We also find that in all cases, the sub-Kelvin regime evinces a common trend across all samples, which may be interpreted within the framework of incoherent tunneling. The application of a magnetic field enables microscopic assessment of two-level systems in δ-FAPbI3, identifying them as intrinsic paramagnetic centers. These findings highlight the universal presence of low-energy excitations in MHPs and their crucial link to dynamic disorder, providing a deeper understanding of the microscopic origins of phase instability and thermal anomalies in this class of materials.
000162998 536__ $$9info:eu-repo/grantAgreement/ES/AEI/PID2020-114506GB-I00$$9info:eu-repo/grantAgreement/ES/AEI/TED2021-129457B-I00$$9info:eu-repo/grantAgreement/ES/MCIN PRE2021-097712$$9info:eu-repo/grantAgreement/ES/MCIU/PID2023-146442NB-I00
000162998 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc$$uhttps://creativecommons.org/licenses/by-nc/4.0/deed.es
000162998 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000162998 700__ $$aMarin-Villa, Pelayo
000162998 700__ $$aDruzbicki, Kacper
000162998 700__ $$aSánchez, María Concepción
000162998 700__ $$aFernandez-Alonso, Felix
000162998 7102_ $$12003$$2395$$aUniversidad de Zaragoza$$bDpto. Física Materia Condensa.$$cÁrea Física Materia Condensada
000162998 773__ $$g(2025), [8 pp.]$$pPhys. chem. chem. phys.$$tPhysical chemistry chemical physics$$x1463-9076
000162998 8564_ $$s1147274$$uhttps://zaguan.unizar.es/record/162998/files/texto_completo.pdf$$yVersión publicada
000162998 8564_ $$s2687950$$uhttps://zaguan.unizar.es/record/162998/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000162998 909CO $$ooai:zaguan.unizar.es:162998$$particulos$$pdriver
000162998 951__ $$a2025-10-09-13:25:53
000162998 980__ $$aARTICLE