Permanent Lattice Compression of Lead-Halide Perovskite for Persistently Enhanced Optoelectronic Properties

Under mild mechanical pressure, halide perovskites show enhanced optoelectronic properties. However, these improvements are reversible upon decompression, and permanent enhancements have yet to be ..

Publisher Correction: Copper adparticle enabled selective electrosynthesis of n-propanol.

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Multi-cation perovskites prevent carrier reflection from grain surfaces

© 2020, The Author(s), under exclusive licence to Springer Nature Limited. The composition of perovskite has been optimized combinatorially such that it often contains six components (AxByC1−x−yPbXzY3−z) in state-of-art perovskite solar cells. Questions remain regarding the precise role of each component, and the lack of a mechanistic explanation limits the practical exploration of the large and growing chemical space. Here, aided by transient photoluminescence microscopy, we find that, in perovskite single crystals, carrier diffusivity is in fact independent of composition. In polycrystalline thin films, the different compositions play a crucial role in carrier diffusion. We report that methylammonium (MA)-based films show a high carrier diffusivity of 0.047 cm2 s−1, while MA-free mixed caesium-formamidinium (CsFA) films exhibit an order of magnitude lower diffusivity. Elemental composition studies show that CsFA grains display a graded composition. This curtails electron diffusion in these films, as seen in both vertical carrier transport and surface potential studies. Incorporation of MA leads to a uniform grain core-to-edge composition, giving rise to a diffusivity of 0.034 cm2 s−1 in CsMAFA films. A model that invokes competing crystallization processes allows us to account for this finding, and suggests further strategies to achieve homogeneous crystallization for the benefit of perovskite optoelectronics

High-Purity Hybrid Organolead Halide Perovskite Nanoparticles Obtained by Pulsed-Laser Irradiation in Liquid

Nanoparticles of hybrid organic-inorganic perovskites have attracted a great deal of attention due to their variety of optoelectronic properties, their low cost, and their easier integration into devices with complex geometry, compared with microcrystalline, thin-film, or bulk metal halides. Here we present a novel one-step synthesis of organolead bromide perovskite nanocrystals based on pulsed-laser irradiation in a liquid environment (PLIL). Starting from a bulk CH3NH3PbBr3 crystal, our PLIL procedure does not involve the use of high-boiling-point polar solvents or templating agents, and runs at room temperature. The resulting nanoparticles are characterized by high crystallinity and are completely free of any microscopic product or organic coating layer. We also demonstrate the straightforward inclusion of laser-generated perovskite nanocrystals in a polymeric matrix to form a nanocomposite with single- and two-photon luminescence properties

Chiral perovskite optoelectronics

Hybrid organic–inorganic perovskites (HOIPs) offer long carrier diffusion lengths, high absorption coefficients, tunable bandgaps and long spin lifetimes. The flexible crystal structure and ionic nature of HOIPs makes it possible to allow tune their material properties through rational design, including the incorporation of chiral organic ligands. Recently, chiral HOIPs have emerged as promising materials for chiroptoelectronics, spintronics and ferroelectricity. They exhibit high photoluminescence polarization (17% without an external magnetic field), good device performance (a circularly polarized photodetector had 100 times higher responsivity than one based on chiral metasurface) and high saturated polarization (~2 times higher than that of barium titanate). Here we review the latest advances in chiral HOIPs and investigate the specific benefits of combining chiral organic and inorganic components in perovskites. We discuss demonstrations of chiroptical and ferroelectric applications, and conclude with our perspective on the future opportunities for chiral HOIPs.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)National Research Foundation (NRF)Accepted versionW.G., G.K.L. and A.S. acknowledge the support from the Singapore National Research Foundation through 2015 NRF fellowship grant (NRF-NRFF2015-03), Singapore Ministry of Education via AcRF Tier2 grant (No. MOE2016-T2-2-077, No. MOE2017- T2-1-163), and A*Star QTE Programme. R.S and G.L. acknowledge the support from the Australian Research Council Centre of Excellence in Exciton Science (Funding grant number CE170100026). E.H.S. acknowledges support from the U.S. Office of Naval Research (grant award no.: N00014-17-1-2524). We thank Prof. Mingtao Zhang (Nankai University) for helpful discussions

(DMP)DAB–Pd–MAH: A Versatile Pd(0) Source for Precatalyst Formation, Reaction Screening, and Preparative-Scale Synthesis

We report an easily prepared and bench-stable mononuclear Pd(0) source stabilized by a chelating N,N’-diaryldiazabutadiene ligand and maleic anhydride: DMPDAB–Pd–MAH. Phosphine ligands of all types, including bidentate phosphines and large cone angle biarylphosphines, rapidly and completely displace the diazabutadiene ligand at room temperature to give air-stable Pd(0) phosphine complexes. DMPDAB–Pd–MAH itself is readily soluble and stable in several organic solvents, making it an ideal Pd source for in situ catalyst preparation during reaction screening, as well as solution-dispensing to plate-based reaction arrays for high-throughput experimentation. Evaluation of DMPDAB–Pd–MAH alongside other common Pd(0) and Pd(II) sources in microscale reaction screens reveals that DMPDAB–Pd–MAH is superior at identifying hits across six different C–N, C–C, and C–O coupling reactions. DMPDAB–Pd–MAH, and the phosphine precatalysts derived therefrom, are also effective in preparative-scale cross couplings at low Pd loadings

Challenges for commercializing perovskite solar cells

Perovskite solar cells (PSCs) have witnessed rapidly rising power conversion efficiencies, together with advances in stability and upscaling. Despite these advances, their limited stability and need to prove upscaling remain crucial hurdles on the path to commercialization. We summarize recent advances toward commercially viable PSCs and discuss challenges that remain. We expound the development of standardized protocols to distinguish intrinsic and extrinsic degradation factors in perovskites. We review accelerated aging tests in both cells and modules and discuss the prediction of lifetimes on the basis of degradation kinetics. Mature photovoltaic solutions, which have demonstrated excellent long-term stability in field applications, offer the perovskite community valuable insights into clearing the hurdles to commercialization