First principal investigation of Structural optical and thermoelectric properties of hybrid organic-inorganic perovskite $[NH_3-(CH_2)_4-NH_3]CdCl_4$ compound
Hafida Ziouani, Sanaa Mazouar, Jean-Pierre Tchapet Njafa, Taoufik Abdelilah, Mahmoud Ettakni, El Mostafa Khechoubi
The structural, thermoelectric, and optical properties of $[NH_3-(CH_2)_4-NH_3]CdCl_4$ were studied using Density Functional Theory (DFT) within the ABINIT code. The GGA-PBE functional, plane wave pseudopotentials, a kinetic energy cutoff of $35Ha$, and an 11x8x8 Monkhorst-Pack $k$-point grid were employed. The material comprises inorganic $[CdCl_4]^{2-}$ sheets, organic $[NH_3-(CH_2)_4-NH_3]^{2+}$ layers, and $N-H-Cl$ hydrogen bonds, ensuring sublattice cohesion. Structural optimization used reference crystal data, enabling analysis of alkylene-diammonium chain conformation, intermolecular interactions, and crystal stability. The study highlights the role of $Cd$ in influencing optical and thermoelectric properties. Temperature-induced changes lead to a reduced band gap and enhanced optical absorption, indicating significant electronic structure modifications. These findings propose $[NH_3-(CH_2)_4-NH_3]CdCl_4$ as a promising candidate for optoelectronic applications, particularly after thermal cycling, due to its improved performance under varying conditions.
Hybrid (organic-inorganic) materials have emerged as a promising class of thermoelectric materials, achieving power factors exceeding those of either constituent. The mechanism of this enhancement is still under debate, and pinpointing the underlying physics has proven difficult. In this work, we combine transport measurements with theoretical simulations and first principles calculations on a prototypical PEDOT:PSS-Te(Cux) nanowire hybrid material system to understand the effect of templating and charge redistribution on the thermoelectric performance. Further, we apply the recently developed…
In spite of intensive studies on the chalcogenides as conventional thermoelectrics, it remains a challenge to find a proper material with high electrical but low thermal conductivities. In this work, we introduced a new class of thermoelectrics, Ge-based inorganic halide perovskites \ce{CsGeX3} (X = I, Br, Cl), which were already known as a promising candidate for photovoltaic applications. By performing the lattice-dynamics calculations and solving the Boltzmann transport equation, we revealed that these perovskites have ultralow thermal conductivities below 0.18 W m$^{-1}$ K$^{-1}$ while ver…
Identifying Highly Deformable van der Waals Layered Chalcogenides with Superior Thermoelectric Performance Using Deformability Factors and Interpretable Machine Learning
Thermoelectric effects enable the direct conversion between thermal and electrical energy and provide an alternative route for power generation and refrigeration. The clathrate Ba8Ga16Ge30 has the highest figure of merit (ZT ~ 1) among other members in the family of type-I inorganic clathrates. Enhancement of the thermoelectric properties have been observed in multilayered superlattices, quantum wires and in nanostructured materials, either due to the increase in power-factor (S^{2}σ) or due to the reduction of lattice thermal conductivity (κ). Here, we investigate the thermoelectric propertie…
Thermoelectric materials can be used to construct devices which recycle waste heat into electricity. However, the best known thermoelectrics are based on rare, expensive or even toxic elements, which limits their widespread adoption. To enable deployment on global scales, new classes of effective thermoelectrics are thus required. $\textit{Ab initio}$ models of transport properties can help in the design of new thermoelectrics, but they are still too computationally expensive to be solely relied upon for high-throughput screening in the vast chemical space of all possible candidates. Here, we …
Organic-inorganic hybrid halide perovskites, in which the A cations of an ABX$_3$ perovskite are replaced by organic cations, may be used for photovoltaic and solar thermoelectric applications. In this contribution, we systematically study three lead-free hybrid perovskites, i.e., methylammonium tin iodide CH$_3$NH$_3$SnI$_3$, ammonium tin iodide NH$_4$SnI$_3$, and formamidnium tin iodide HC(NH$_2$)$_2$SnI$_3$, by first-principles calculations. We find that in addition to the commonly known motif in which the corner-shared SnI$_6$ octahedra form a three-dimensional network, these materials may…
Organic semiconductors have attracted increasing interest as thermoelectric converters in recent years due to their intrinsically low thermal conductivity compared to inorganic materials. This boom has led to encouraging practical results, in which the thermal conductivity has predominantly been treated as an empirical number. However, in an optimized thermoelectric material, the electronic component can dominate the thermal conductivity in which case the figure of merit $ZT$ becomes a function of thermopower and Lorentz factor only. Hence design of effective organic thermoelectric materials r…
Learning Thermoelectric Transport from Crystal Structures via Multiscale Graph Neural Network
School of Integrated Circuits, Wuhan University（武汉大学集成电路学院）；Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University（武汉大学物理科学与技术学院人工微结构和介观物理教育部重点实验室）；School of Optical and Electronic Information, Huazhong University of Science and Technology（华中科技大学光学与电子信息学院）
Singapore-MIT Alliance for Research and Technology（新加坡-麻省理工学院研究与技术联盟）；National University of Singapore（新加坡国立大学）；Korea Advanced Institute of Science and Technology（韩国科学技术院）；Massachusetts Institute of Technology（麻省理工学院）；Okinawa Institute of Science and Technology Graduate University（冲绳科学技术大学院大学）；Agency for Science, Technology and Research（新加坡科技研究局）；Nanyang Technological University（南洋理工大学）；Shanghai University（上海大学）；Microsoft AI for Good（微软人工智能公益计划）；Toyota Research Institute（丰田研究院）；Tsinghua University（清华大学）
Realizing general inverse design could greatly accelerate the discovery of new materials with user-defined properties. However, state-of-the-art generative models tend to be limited to a specific composition or crystal structure. Herein, we present a framework capable of general inverse design (not limited to a given set of elements or crystal structures), featuring a generalized invertible representation that encodes crystals in both real and reciprocal space, and a property-structured latent space from a variational autoencoder (VAE). In three design cases, the framework generates 142 new cr…
