Journal of the American Chemical Society (J AM CHEM SOC)

Publisher: American Chemical Society; American Chemical Society; Marian S. Carson Collection (Library of Congress), American Chemical Society

Journal description

The Journal of the American Chemical Society, founded in 1879, is the flagship journal of the American Chemical Society and a highly esteemed journal in the field. This periodical is devoted to the publication of research papers in all fields of chemistry and publishes approximately 13,000 pages of new chemistry a year. Published weekly, JACS provides research crucial to the field of chemistry. The Journal of the American Chemical Society publishes articles, communications to the Editor, book reviews, and computer software reviews.

Current impact factor: 12.11

Impact Factor Rankings

2015 Impact Factor Available summer 2016
2014 Impact Factor 12.113
2013 Impact Factor 11.444
2012 Impact Factor 10.677
2011 Impact Factor 9.907
2010 Impact Factor 9.019
2009 Impact Factor 8.58
2008 Impact Factor 8.091
2007 Impact Factor 7.885
2006 Impact Factor 7.696
2005 Impact Factor 7.419
2004 Impact Factor 6.903
2003 Impact Factor 6.516
2002 Impact Factor 6.201
2001 Impact Factor 6.079
2000 Impact Factor 6.025
1999 Impact Factor 5.537
1998 Impact Factor 5.725
1997 Impact Factor 5.65
1996 Impact Factor 5.948
1995 Impact Factor 5.263
1994 Impact Factor 5.039
1993 Impact Factor 5.365
1992 Impact Factor 5.298

Impact factor over time

Impact factor

Additional details

5-year impact 11.73
Cited half-life 8.00
Immediacy index 2.61
Eigenfactor 0.82
Article influence 3.29
Website Journal of the American Chemical Society website
Other titles Journal of the American Chemical Society, Review of American chemical research
ISSN 0002-7863
OCLC 1226990
Material type Periodical, Internet resource
Document type Journal / Magazine / Newspaper, Internet Resource

Publisher details

American Chemical Society

  • Pre-print
    • Author cannot archive a pre-print version
  • Restrictions
    • Must obtain written permission from Editor
    • Must not violate ACS ethical Guidelines
  • Post-print
    • Author cannot archive a post-print version
  • Restrictions
    • If mandated by funding agency or employer/ institution
    • If mandated to deposit before 12 months, must obtain waiver from Institution/Funding agency or use AuthorChoice
    • 12 months embargo
  • Conditions
    • On author's personal website, pre-print servers, institutional website, institutional repositories or subject repositories
    • Non-Commercial
    • Must be accompanied by set statement (see policy)
    • Must link to publisher version
    • Publisher's version/PDF cannot be used
    • If mandated sooner than 12 months, must obtain waiver from Editors or use AuthorChoice
    • Reviewed on 07/08/2014
  • Classification

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Linckosides A and B, two starfish metabolites with promising neuritogenic activities, are synthesized in a longest linear sequence of 32 steps and 0.5% overall yield; this represents the first synthesis of members of the polyhydroxysteroid glycoside family which occur widely in starfishes.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b11276
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    ABSTRACT: We have investigated the relationship between driving force and rate for interfacial hole transfer from quantum dots (QDs). This relationship is experimentally explored by using six distinct molecular hole acceptors with an 800 meV range in driving force. Specifically, we have investigated ferrocene derivatives with alkyl thiol moieties that strongly bind to the surface of cadmium chalcogenide QDs. The redox potentials of these ligands are controlled by functionalization of the cyclopentadiene rings on ferrocene with electron withdrawing and donating substituents, thus providing an avenue for tuning the driving force for hole transfer while holding all other system parameters constant. The relative hole transfer rate from photoexcited CdSe/CdS core/shell QDs to tethered ferrocene derivatives is determined by measuring the photoluminescence quantum yield of these QD-molecular conjugates at varying ferrocene coverage, as determined via quantitative NMR. The resulting relationship between rate and energetic driving force for hole transfer is not well modeled by the standard two-state Marcus model, since no inverted region is observed. Alternative mechanisms for charge transfer are posited, including an Auger-assisted mechanism that provides a successful fit to the results. The observed relationship can be used to design QD-molecular systems that maximize interfacial charge transfer rates while minimizing energetic losses associated with the driving force.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10856
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    ABSTRACT: Stable carbocations such as tritylium ions have been widely explored as organic Lewis acid catalysts and reagents in organic synthesis. However, to achieve asymmetric carbocation catalysis remains elusive ever since their first identification over one century ago. The challenges mainly come from their limited compatibility, scarcity of chiral carbocation as well as the extremely low barrier to racemization of chiral carbenium ions. We reported herein a latent concept for asymmetric carbocation catalysis. In this strategy, chiral trityl phosphate is employed as the carbocation precursor, which undergoes facile ionic dissociation upon mild external stimulation (e.g. acid, H-bonding, polar substrates) to form a catalytically active chiral ion-pair for substrate activation and chiral induction. The latent strategy provides an enabling solution to the long sought-after asymmetric carbocation catalysis as illustrated in three different enantioselective transformations.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b11085
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    ABSTRACT: Accomplishing high diastereo- and enantio-selectivities simultaneously is a persistent challenge in asymmetric catalysis. The use of two chiral catalysts in one-pot conditions might offer new avenues to this end. Chirality transfer from a catalyst to product gets increasingly complex due to potential chiral match-mismatch issues. The origin of high enantio- and diastereo-selectivities in the reaction between a racemic aldehyde and an allyl alcohol, catalyzed by using axially chiral iridium phosphoramidites PR/S-Ir and cinchona amine is established through transition state modeling. The multi-point contact analysis of the stereocontrolling transition state revealed how the stereodivergence could be achieved by inverting the configuration of the chiral catalysts that are involved in the activation of the reacting partners. While the enantiocontrol is identified as being decided in the generation of PR/S-Ir-π-allyl intermediate from the allyl alcohol, the diastereocontrol arises due to the differential stabilizations in the C-C bond formation transition states. The analysis of the weak interactions in the transition states responsible for chiral induction revealed that the geometric disposition of the quinoline ring at the C8 chiral carbon of cinchona-enamine plays an anchoring role. The quinolone ring is noted as participating in a π-stacking interaction with the phenyl ring of the Ir-π-allyl moiety in the case of PR with (8R,9R)-cinchona catalyst combination whereas a series of C-H···π interactions is identified as vital to the relative stabilization of the stereocontrolling transition states when PR is used with (8S,9S)-cinchona.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b05902
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    ABSTRACT: Direct synthesis (H2 + O2 → H2O2) is a promising reaction for producing H2O2, which can replace chlorinated oxidants in industrial processes. The mechanism of this reaction, and the reasons for the importance of seemingly unrelated factors (e.g., Pd cluster size, solvent pH), remain unclear despite significant research. We propose a mechanism for H2O2 formation on Pd clusters consistent with steady-state H2O2 and H2O formation rates measured as functions of reactant pressures and temperature, and the interpretations of proton concentration effects. H2O2 forms by sequential proton-electron transfer to O2 and OOH surface intermediates, whereas, H2O forms by O-O bond rupture within OOH surface species. Direct synthesis, therefore, does not proceed by the Langmuir-Hinshelwood mechanism often invoked. Rather, H2O2 forms by heterolytic reaction pathways resembling the two electron oxygen reduction reaction (ORR), however, the chemical potential of H2 replaces an external electrical potential as the thermodynamic driving force. Activation enthalpies (∆H(‡) ) for H2O formation increase by 14 kJ mol(-1) when Pd cluster diameters increase from 0.7 to 7 nm, because changes in the electronic structure of Pd surface atoms decrease their propensity to cleave O-O bonds. ∆H(‡) values for H2O2 remain nearly constant, because barriers for proton-electron transfer depend weakly on the coordinative saturation of Pd surface atoms. Collectively, these results provide a self-consistent mechanism, which clarifies many studies in which H2O2 rates and selectivities were shown to depend on the concentration of acid/halide additives, and Pd cluster size. These findings will guide the rational design of selective catalysts for direct synthesis.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10669
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    ABSTRACT: A synthetic approach to paxilline indole diterpenes is described. The route to the pentacyclic core relies on a new regioselective alkenylation of ketones and a tandem radical addition-aldol reaction sequence to access vicinal quaternary stereocenters. Emindole SB, the simplest member of the family, is synthesized in 11 steps from commercially available material to demonstrate the application of this approach.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b11129
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    ABSTRACT: A series of chiral synthetic compounds is reported that show intricate but specific hierarchical assembly because of varying positions of coordination and hydrogen bonds. The evolution of the aggregates (followed by absorption spectroscopy and temperature-dependent circular dichroism studies in solution) reveal the influence of the proportion of stereogenic centers in the side groups connected to the chromophore ring in their optical activity and the important role of pyridyl groups in the self-assembly of these chiral macrocycles. The optical activity spans two orders of magnitude depending on composition and constitution. Two of the aggregates show very high optical activity even though the isolated chromophores barely give a circular dichroism signal. Molecular modeling of the aggregates, starting from the pyridine-zinc(II) porphyrin interaction and working up, and calculation of the circular dichroism signal confirm the origin of this optical activity as the chiral supramolecular organization of the molecules. The aggregates show a broad absorption range, between approximately 390 and 475 nm for the transitions associated with the Soret region alone, that spans wavelengths far more than the isolated chromophore. The supramolecular assemblies of the metalloporphyrins in solution were deposited onto highly oriented pyrolitic graphite in order to study their hierarchy in assembly by atomic force microscopy. Zero and one-dimensional aggregates were observed, and a clear dependence on deposition temperature was shown, indicating that the hierarchical assembly took place largely in solution. Moreover, scanning electron microscopy images of porphyrins and metalloporphyrins precipitated under out-of-equilibrium conditions showed the dependence of the number and position of chiral amide groups in the formation of a fibrillar nanomaterial. The combination of coordination and hydrogen bonding in the complicated assembly of these molecules - where there is a clear hierarchy for zinc(II)-pyridyl interaction followed by hydrogen-bonding between amide groups, and then van der Waals interactions - paves the way for the preparation of molecular materials with multiple chromophore environments.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b08081
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    ABSTRACT: A series of three-dimensional (3D) extended metal catecholates (M-CATs) was synthesized by combining the appropriate metal salt and the hexatopic catecholate linker, H6THO (THO(6-) = triphenylene-2,3,6,7,10,11-hexakis(olate)) to give Fe(THO)·Fe(SO4)(DMA)3, Fe-CAT-5, Ti(THO)⋅(DMA)2, Ti-CAT-5, and V(THO)⋅(DMA)2, V-CAT-5 (where DMA = dimethylammonium). Their structures are based on the srs topology and are either a two-fold interpenetrated (Fe-CAT-5 and Ti-CAT-5) or non-interpenetrated (V-CAT-5) porous anionic framework. These examples are among the first catecholate-based 3D frameworks. The single crystal X-ray diffraction structure of Fe-CAT-5 shows bound sulfate ligands with DMA guests residing in the pores as counter ions, and thus ideally suited for proton conductivity. Accordingly, Fe-CAT-5 exhibits ultrahigh proton conductivity (5.0 × 10(-2) S cm(-1)) at 98% relative humidity (RH) and 25 °C. The co-existence of sulfate and DMA ions within the pores play an important role in proton conductivity as also evidenced by the lower conductivity values found for Ti-CAT-5 (8.2 × 10(-4) S cm(-1) at 98% RH and 25 °C), whose structure only contained DMA guests.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10999
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    ABSTRACT: Controlling the dopant type, number and position in doped metal nanoclusters (nanoparticles) is crucial but challenging. Herein, we successfully achieved the mono-cadmium doping of Au25 nanoclusters, and revealed using X-ray crystallography in combination with theoretical calculations that one of the inner-shell gold atoms of Au25 was replaced by a cadmium atom. The doping mode is distinctly different from that of mono-mercury doping, where one of the outer-shell gold atoms was replaced by a mercury atom. Au24Cd is readily transformed to Au24Hg, while the reverse (transformation from Au24Hg to Au24Cd) is forbidden in investigated conditions.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b09627
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    ABSTRACT: Fluorinated boronic acid-appended benzyl bipyridinium salts, derived from 4,4'-, 3,4'- and 3,3'-bipyiridines, were synthesized and used to detect and differentiate diol-containing analytes at physiological conditions via 19F NMR spectroscopy. An array of three water-soluble boronic acid receptors in combination with 19F NMR spectroscopy discriminates nine diol-containing bioanalytes, such as catechol, dopamine, fructose, glucose, glucose-1-phosphate, glucose-6-phosphate, galactose, lactose and sucrose at low mM concentrations. Characteristic 19F NMR fingerprints are interpreted as two-dimensional barcodes without the need of multivariate analysis techniques.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10934
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    ABSTRACT: Pseudoknots are a fundamental RNA tertiary structure with important roles in regulation of mRNA translation. Molecular force spectroscopic approaches such as optical tweezers can track the pseudoknot's unfolding intermediate states by pulling the RNA chain from both ends, but the kinetic unfolding pathway induced by this method may be different from that in vivo, which occurs during translation and proceeds from the 5' to 3' end. Here we developed a ribosome-mimicking, nanopore pulling assay for dissecting the vectorial unfolding mechanism of pseudoknots. The pseudoknot unfolding pathway in the nanopore, either from the 5' to 3' end or in the reverse direction, can be controlled by a DNA leader that is attached to the pseudoknot at the 5' or 3' ends. The different nanopore conductance between DNA and RNA translocation serves as a marker for the position and structure of the unfolding RNA in the pore. With this design, we provided evidence that the pseudoknot unfolding is a two-step, multi-state, metal ion-regulated process depending on the pulling direction. Most notably, unfolding in both directions is rate-limited by the unzipping of the first helix domain (first step), which is Helix-1 in the 5'→3' direction and Helix-2 in the 3'→5' direction, suggesting that the initial unfolding step in either pulling direction needs to overcome an energy barrier contributed by the non-canonical triplex base-pairs and coaxial stacking interactions for the tertiary structure stabilization. These findings provide new insights into RNA vectorial unfolding mechanisms, which play an important role in biological functions including frameshifting.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b07910
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    ABSTRACT: In perovskite based planar heterojunction solar cells, the interface between TiO2 compact layer and perovskite film is critical for high photovoltaic performance. The deep trap states on TiO2 surface induce several challenging issues, such as charge recombination loss and poor stability etc. To solve the problems, we synthesized a tri-block fullerene deriva-tive (PCBB-2CN-2C8) via rational molecular design for interface engineering in the perovskite solar cells. Modifying TiO2 surface with the compound significantly improves charge extraction from perovskite layer. Together with its up-lifted surface work function, open circuit voltage and fill factor are dramatically increased from 0.99 V to 1.06 V, and from 72.2% to 79.1%, respectively, resulting in 20.7% improvement in power conversion efficiency for the best perform-ing devices. Scrutinizing the electrical properties of this modified interfacial layer strongly suggests that PCBB-2CN-2C8 passivates TiO2 surface and thus reduces charge recombination loss caused by the deep trap states of TiO2. The pas-sivation effect is further proved by stability testing of the perovskite solar cells with shelf lifetime in ambient condition improved by a factor of more than 4, from ~40 hours to ~200 hours, by using the PCBB-2CN-2C8 as TiO2 modification layer. This work offers not only a promising material for cathode interface engineering, but also provides a viable ap-proach to address the challenges of deep trap states on TiO2 surface in planar perovskite solar cells.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10614
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    ABSTRACT: The cobalt cubium Co4O4(OAc)4(py)4(ClO4) (1A+) containing the mixed valence [Co4O4]5+ core is shown by multiple spectroscopic methods to react with hydroxide (OH-) but not with water molecules to produce O2. The yield of reaction products is stoichiometric (>99.5%): 4 1A+ + 4 OH- → O2 + 2 H2O + 4 1A. By contrast, the structurally ho-mologous cubium Co4O4(trans-OAc)2(bpy)4(ClO4)3, 1B(ClO4)3 produces no O2. EPR/NMR spectroscopies show clean conversion to cubane 1A during O2 evolution with no Co2+ or Co3O4 side products. Mass spectrometry of the reac-tion between isotopically labeled µ-16O(bridging-oxo) 1A+ and 18O-bicarbonate/water shows: 1) no exchange of 18O into the bridging oxos of 1A+, and 2) 36O2 is the major product, thus requiring two OH- in the reactive intermediate. DFT calculations of solvated intermediates suggest that addition of two OH- to 1A+ via OH- insertion into Co-OAc bonds is energetically favored, followed by outer-sphere oxidation to intermediate [1A(OH)2]0. The absence of O2 production by cubium 1B3+ indicates the reactive intermediate derived from 1A+ requires gem-1,1-dihydoxo stereochemistry to perform O-O bond formation. Outer-sphere oxidation of this intermediate by 2 eq. 1A+ accounts for the final stoichiometry. Collectively, these results, and recent literature (Faraday Disc., doi:10.1039/C5FD00076A and J.Am.Chem.Soc 2015, 12865-12872) validate the [Co4O4]4+/5+ cubane core as an intrinsic catalyst for oxidation of hydroxide by an inner-sphere mechanism.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b09152
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    ABSTRACT: The spectroscopically observable tris(thiolate) complex [Ru(dppbt)3]+ (1+) (dppbt = diphenylphosphinobenzenethiolate) is reported to have chemistry based on thyil-radical character. High-level ab initio methods predict the ground state electronic structure of 1+ to be an open shell diradical singlet state with an anti-ferromagnetic coupling between (S = 1/2) Ru(III) and (S = 1/2) S pz, rather the previous description based on a diradical state involving two S p orbitals. These new results provide an improved understanding of the experimental chemistry of 1+ and related species.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b09309
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    ABSTRACT: Realizing the promise of nanoparticle-based technologies demands more efficient, robust synthesis methods (i.e., process intensification) that consistently produce high-quality and large-quantities of nanoparticles (NPs). We explored NP synthesis via the heat-up method in a regime of previously unexplored high concentrations near the solubility limit of the precursors. We discovered that in this highly concentrated and viscous regime the NP synthesis parameters are less sensitive to experimental variability and thereby provide a robust, scalable, and size-focusing NP synthesis. Specifically, we synthesize high-quality metal sulfide NPs (< 7% relative standard deviation for Cu2-xS, CdS, and PbS), and demonstrate 10-1000 fold increase in Cu2-xS NP production (>200 g) relative to the current field of large-scale (0.1-5 g yields) and lab-scale (<0.1 g) efforts. Compared to conventional synthesis methods (hot-injection with dilute precursor concentration) characterized by rapid growth and low yield, our highly concentrated NP system supplies remarkably controlled growth rates and a ten-fold increase in NP volumetric production capacity (72 g NPs/L). The controlled growth, high yield, and robust nature of highly concentrated solutions can facilitate large-scale nano-manufacturing of NPs by relaxing synthesis requirements to achieve monodisperse products. Mechanistically, our investigation of the thermal and rheological properties, and growth rates reveals that this high concentration regime has an order of magnitude increase in solution viscosity, reducing mass diffusion, a ~67% in heat capacity, stabilizing the reaction to perturbations, and the decreasing influence of Ostwald ripening.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10006
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    ABSTRACT: Light harvesting supramolecular assemblies are potentially useful structures as components of solar-to-fuel conversion materials. The development of these functional constructs requires an understanding of optimal packing modes for chromophores. We investigated here assembly in water and the photocatalytic function of perylene monoimide chromophore amphiphiles with different alkyl linker lengths separating their hydrophobic core and the hydrophilic carboxylate headgroup. We found that these chromophore amphiphiles (CAs) self-assemble into charged nanostructures of increasing aspect ratio as the linker length is increased. The addition of salt to screen the charged nanostructures induced the formation of hydrogels and led to internal crystallization within some of the nanostructures. For linker lengths up to seven methylenes, the CAs were found to pack into 2D crystalline unit cells within ribbon-shaped nanostructures, whereas the nine methylene CAs assembled into long nanofibers without crystalline molecular packing. At the same time, the different molecular packing arrangements after charge screening led to different absorbance spectra, despite the identical electronic properties of all PMI amphiphiles. While the crystalline CAs formed electronically coupled H-aggregates, only CAs with intermediate linker lengths showed evidence of high intermolecular orbital overlap. Photocatalytic hydrogen production using a nickel-based catalyst was observed in all hydrogels, with the highest turnovers observed for CA gels having intermediate linker lengths. We conclude that the improved photocatalytic performance of the hydrogels formed by supramolecular assemblies of the intermediate linker CA molecules likely arises from improved exciton splitting efficiencies due to their higher orbital overlap.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10027
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    ABSTRACT: Direct observation of gas molecules confined in the nanospace of porous materials by single crystal X-ray diffraction (SXRD) technique is significant because it leads to deep insight into the adsorption mechanism and the actual state of the adsorbents in molecular level. Recent study revealed that flexibility is one of the important factors to achieve periodic guest accommoda-tion in the nanospace enabling direct observation of gas molecules. Here, we report a convenient strategy to tune the framework flexibility by just an atomic exchange in a ligand, which enables us to easily construct a soft nanospace as the best platform to study gas adsorption. Indeed, we succeeded to observe C2H2 and CO2 molecules confined in the pores of a flexible porous coordination polymer (PCP-N) in different configurations using SXRD measurement, whereas gas molecules in a rigid framework (PCP-C) isostructural to PCP-N were not seen crystallographically. The result of the coincident in situ powder X-ray diffraction and adsorption measurement for PCP-N unambiguously showed that the framework could flexibly transform to trap gas molecules with commensurate fashion. In addition, for PCP-N, we found that the adsorbed gas molecules induced significant structural change involving dimensional change of the pore from one-dimensional to three-dimensional and subsequently additional gas molecules formed periodic molecular clusters in the nanospace.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b09666
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    ABSTRACT: Solution-processed lead halide perovskite thin-film solar cells have achieved power conversion efficiencies comparable to those obtained with several commercial photovoltaic technologies in a remarkably short period of time. This rapid rise in device efficiency is largely the result of the development of fabrication protocols capable of producing continuous, smooth perovskite films with micrometer-sized grains. Further developments in film fabrication and morphological control are necessary, however, in order for perovskite solar cells to reliably and reproducibly approach their thermodynamic efficiency limit. This Perspective discusses the fabrication of lead halide perovskite thin films, while highlighting the processing-property-performance relationships that have emerged from the literature, and from this knowledge, suggests future research directions.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b10723