Optical Fingerprints of Polynuclear Complexes in Lead Halide Perovskite Precursor Solutions.
02 Mar 2021-Journal of Physical Chemistry Letters (The American Chemical Society (ACS))-Vol. 12, Iss: 9, pp 2299-2305
TL;DR: In this article, the optical spectra of the quasi-one-dimensional iodoplumbate complexes PbI2(DMSO)4, Pb2I4(DSO)6, and Pb3I6(DsO)8 formed in dimethyl sulfoxide solutions are compatible with the spectral fingerprints measured at high lead iodide concentrations.
Abstract: Solvent-solute interactions in precursor solutions of lead halide perovskites (LHPs) critically impact the quality of solution-processed materials, as they lead to the formation of a variety of poly-iodoplumbates that act as building blocks for LHPs. The formation of [PbI2+n]n- complexes is often expected in diluted solutions, while coordination occurring at high concentrations is not yet well understood. In a combined ab initio and experimental work, we demonstrate that the optical spectra of the quasi-one-dimensional iodoplumbate complexes PbI2(DMSO)4, Pb2I4(DMSO)6, and Pb3I6(DMSO)8 formed in dimethyl sulfoxide solutions are compatible with the spectral fingerprints measured at high lead iodide concentrations. This finding suggests that the interpretation of optical spectra of LHP precursor solutions should account for the formation of polynuclear lead halide complexes.
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University of Konstanz1, University of Würzburg2, University of Cologne3, University of Duisburg-Essen4, University of Oxford5, TUM Institute for Advanced Study6, University of Tübingen7, Dresden University of Technology8, University of Regensburg9, Technische Universität München10, Helmholtz-Zentrum Berlin11, University of Oldenburg12, University of Stuttgart13, University of Luxembourg14, University of Potsdam15, Fraunhofer Society16, University of Freiburg17, University of Bayreuth18, Technische Universität Darmstadt19, University of Erlangen-Nuremberg20, Technical University of Berlin21, University of Wuppertal22, Max Planck Society23, Princeton University24, Ludwig Maximilian University of Munich25, University of Rome Tor Vergata26, National University of Science and Technology27, Fritz Haber Institute of the Max Planck Society28, Humboldt University of Berlin29
TL;DR: In this article, a comprehensive overview of perovskite semiconductors is presented and an informed perspective of where this field is heading and what challenges we have to overcome to get to successful commercialization.
Abstract: Metal halide perovskites are the first solution processed semiconductors that can compete in their functionality with conventional semiconductors, such as silicon. Over the past several years, perovskite semiconductors have reported breakthroughs in various optoelectronic devices, such as solar cells, photodetectors, light emitting and memory devices, and so on. Until now, perovskite semiconductors face challenges regarding their stability, reproducibility, and toxicity. In this Roadmap, we combine the expertise of chemistry, physics, and device engineering from leading experts in the perovskite research community to focus on the fundamental material properties, the fabrication methods, characterization and photophysical properties, perovskite devices, and current challenges in this field. We develop a comprehensive overview of the current state-of-the-art and offer readers an informed perspective of where this field is heading and what challenges we have to overcome to get to successful commercialization.
81 citations
TL;DR: In this article , the amount of residual DMSO can be reduced in as-spin-coated films significantly through use of preheated substrates, or a so-called hot casting method.
Abstract: High‐performance inorganic–organic lead halide perovskite solar cells (PSCs) are often fabricated with a liquid additive such as dimethyl sulfoxide (DMSO), which retards crystallization and reduces roughness and pinholes in the perovskite layers. However, DMSO can be trapped during perovskite film formation and induce voids and undesired reaction byproducts upon later processing steps. Here, it is shown that the amount of residual DMSO can be reduced in as‐spin‐coated films significantly through use of preheated substrates, or a so‐called hot‐casting method. Hot casting increases the perovskite film thickness given the same concentration of solutions, which allows for reducing the perovskite solution concentration. By reducing the amount of DMSO in proportion to the concentration of perovskite precursors and using hot casting, it is possible to fabricate perovskite layers with improved perovskite–substrate interfaces by suppressing the formation of byproducts, which increase trap density and accelerate degradation of the perovskite layers. The best‐performing PSCs exhibit a power conversion efficiency (PCE) of 23.4% (23.0% stabilized efficiency) under simulated solar illumination. Furthermore, encapsulated devices show considerably reduced post‐burn‐in decay, retaining 75% and 90% of their initial and post‐burn‐in efficiencies after 3000 h of operation with maximum power point tracking (MPPT) under high power of ultraviolet (UV)‐containing continuous light exposure.
12 citations
13 Sep 2021
TL;DR: In this article, the so-called "chlorine rout" is used to control perovskite growth from solution, which is crucial for efficient optoelectronic applications.
Abstract: Controlled perovskite growth from solution is crucial for efficient optoelectronic applications and requires a deep understanding of the perovskite precursor chemistry. The so-called “chlorine rout...
8 citations
TL;DR: In this article , a combination of density functional theory (DFT) calculations and ab-initio molecular dynamics (AIMD) simulations is used to study the complex evolution of the molecular species from the solution to the initial stage of the crystallization.
6 citations
TL;DR: In this paper, the role of halogen species and solvent molecules in the formation of lead halide (LH) perovskite solution precursors was investigated using density-functional theory in conjunction with the polarizable continuum model.
Abstract: Understanding the formation of lead halide (LH) perovskite solution precursors is crucial to gain insight into the evolution of these materials to thin films for solar cells. Using density-functional theory in conjunction with the polarizable continuum model, we investigate 18 complexes with chemical formula PbX$_2$M$_4$, where X = Cl, Br, I and M are common solvent molecules. Through the analysis of structural properties, binding energies, and charge distributions, we clarify the role of halogen species and solvent molecules in the formation of LH perovskite precursors. We find that interatomic distances are critically affected by the halogen species, while the energetic stability is driven by the solvent coordination to the backbones. Regardless of the solvent, lead iodide complexes are more strongly bound than the others. Based on the charge distribution analysis, we find that all solvent molecules bind covalently with the LH backbones and that Pb-I and Pb-Br bonds lose ionicity in solution. Our results contribute to clarify the physical properties of LH perovskite solution precursors and offer a valuable starting point for further investigations on their crystalline intermediates.
3 citations
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