aspuru-list November 2017

aspuru-list@lists.fas.harvard.edu

23 participants
58 discussions

[Aspuru-Guzik Group List] [qip] IBM Quantum Internships

by Ramis Movassagh

Dear all, There is a call for internships at IBM Quantum. Most positions will be at Yorktown Heights, but we might also have an opening or two in the Cambridge office: These are the links to the positions. Please feel free to distribute to others who might be interested and not be on this mailing list: Graduate https://krb-sjobs.brassring.com/TGnewUI/Search/Home/HomeWithPreLoad?partner… Undergrad https://krb-sjobs.brassring.com/TGnewUI/Search/Home/HomeWithPreLoad?partner… -- Ramis _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

6 years, 5 months

[Aspuru-Guzik Group List] FW: [rle-admins] Professor Shigeo Maruyama - "Carbon Nanotubes and Graphene for Perovskite Solar Cells" - 12 pm Tuesday, November 28, 2017- 35-225- Joint Micro-Nano and LMP Seminar Series

by Catherine M Bourgeois

[color_print] Micro-nano Seminar Series Joint Micro-Nano / LMP Seminar ________________________________ Tuesday, November 28, 2017 12:00 pm - 35-225 Professor Shigeo Maruyama Department of Mechanical Engineering The University of Tokyo Energy NanoEngineering Laboratory National Institute of Advanced Industrial Science and Technology,Tsukuba, Japan Carbon Nanotubes and Graphene for Perovskite Solar Cells Abstract Single-walled carbon nanotubes (SWNT), graphene, and fullerene (C60 and PCBM) would be very efficiently used in lead halide Perovskite solar cells. A film of SWNTs or graphene can be flexible and stretchable transparent-conductive layer. At the same time, this film can be carrier-selective layers, i.e., electron-blocking-layers or hole-blocking-layers. Based on our experiences of using nanotube films for CNT-Si solar cells [1] and organic polymer solar cells [2,3], we have explored the application of SWNT films for organic-inorganic perovskite solar cells. We have demonstrated the replacement of ITO in inverted-type perovskite solar cells,SWNTs/PEDOT:PSS/CH3NH3PbI3/PCBM/Al [4]. The flexible application on polyethylene terephthalate (PET) is also demonstrated [4]. With the improved perovskite structure, a film of carbon nanotubes or graphene can be practical replacement of ITO for the flexible transparent electrode of inverted perovskite solar cells [5]. This work was supported by JSPS KAKENHI Grant Numbers JP25107002 and JP15H05760. [ShigeoMaruyama]Biography Professor Shigeo Maruyama received his Ph.D. from the School of Engineering at the University of Tokyo in 1988. Since 2014, he is a Distinguished Professor at the University of Tokyo. From April 2015, he works as a cross-appointment fellow for Advanced Industrial science and technology (AIST) in Japan. From 2016, he is also serving as guest professor at Peking University. Prof. Maruyama has served as a program officer of Japan Society for the Promotion of Science (JSPS) during 2009-2012, and as the president of "The Fullerenes, Nanotubes and Graphene Research Society," since 2011, and the co-chair of steering committee of Carbon Nanotube conferences. He also served as Director of The Japan Society of Applied Physics since 2014 and as Executive Director in 2015. He has published more than 210 ISI-listed papers which have been cited more than 9,000 times, resulting the h-index of 50 (Google Scholar shows 15, 832 citations and h-index 64). Host: Professor Anastasios John Hart: ajhart(a)mit.edu<mailto:ajhart@mit.edu> Refreshments Provided Thank you, Emilie Heilig Massachusetts Institute of Technology 77 Massachusetts Ave, 3-359 (32 Vassar St, 3-359 for packages) Cambridge, MA 02139 P: 617-253-2883

6 years, 5 months

[Aspuru-Guzik Group List] Vacation

by Felixander Negron

Good afternoon, Just wanted to give you all a heads up that I will be out of the office beginning this Thursday afternoon and will return on Monday, December 11th. If you need anything from me, please be sure to contact me before my departure. Thanks, Felix *Felixander Negron* *Laboratory Administrator * *Aspuru-Guzik Group* *Harvard University * *Department of Chemistry and Chemical Biology* *12 Oxford St. M 136* *Cambridge, MA 02138* *P:** (617) 496-9964** F: **617-496-9411*

6 years, 5 months

[Aspuru-Guzik Group List] Practice GAC meeting

by Jennifer Wei

Hi all, I'm going to give a practice GAC meeting on Wednesday, Nov. 29 at 11am in the Division Room. Title and abstract are below. If you'd like to come and help me practice, or are interested in hearing about the current state of molecular autoencoders, feel free to come. Thanks! Jennifer Title: Semi-supervised learning for Molecular Autoencoders Abstract: Molecular autoencoders are capable of encoding molecules into a continuous vector representation. This encoding can then be used to map to properties, and even to optimize for properties. However, this autoencoder requires a large dataset in order to learn an accurate encoding. I will describe how semi-supervised learning can be used to help the molecular autoencoder learn from a smaller dataset.

6 years, 5 months

[Aspuru-Guzik Group List] Exctionics Seminar: Tomorrow, Nov 28 at 4:30pm in 34-401A

by Catherine M Bourgeois

Please post and forward to your groups. Center for Excitonics Seminar Series presents: Exciting Metal-organic Frameworks: Electrons, Phonons, and Photons November 28, 2017 at 4:30pm/rm: 34-401A Aron Walsh Department of Materials, Imperial College London [http://www.rle.mit.edu/excitonics/wp-content/uploads/2017/10/1Walsh-Aron-27…] Metal-organic frameworks (MOFs) are porous ordered arrays of inorganic clusters supported by organic linking units. They have attracted attention for gas storage, separation and catalysis, which rely on weak chemical bonding with an absorbate. The recent focus has shifted to physical responses, with examples of magnetic, optical, ferroelectric, and photovoltaic compounds. I will discuss progress in the understanding of how hybrid frameworks interact with charge, heat, and light. The optical response of MOFs can be tuned by chemical modification of the organic and inorganic building blocks[1]. The control of electrical conductivity and redox activity in MOF thin-films is opening a new dimension of applications[2,3]. The combination of chemical diversity, mechanical flexibility, and electronic control in a single family of compounds could enable metal-organic frameworks to become the semiconductors of the future. Beyond porous frameworks, I will also discuss progress in the understanding of organic-inorganic halide perovskites, such as methylammonium lead iodide, which have attracted significant attention for solar energy conversion. These compounds have been termed ‘plastic crystals’ owing to the rotational-vibrational activity of the molecular components, as well as the large anharmonic thermal displacements of the inorganic framework. We have been developing models to describe the temporal behaviour of hybrid perovskites that have been validated through a combination of quasi-elastic neutron scattering, time-resolved vibrational spectroscopy, and inelastic X-ray scattering. There remains significant challenges relating to the fundamental chemistry and physics of this growing family of hybrid compounds. This research has been supported by the Royal Society and the European Research Council, with a wide collaboration network including simulations by Drs. Katrine Svane, Jarvist Frost, and Jonathan Skelton. 1. “Chemical principles for electroactive metalâ€“organic frameworks” MRS Bulletin 41, 870 (2016) 2. “Metallic conductivity in a two-dimensional cobalt dithiolene metalâˆ’organic framework” J. Am. Chem. Soc. 139, 10863 (2017) 3. “Is iron unique in promoting electrical conductivity in MOFs?” Chemical Science 8, 4450 (2017) 4. â€œAtomistic origins of high-performance in hybrid halide perovskite solar cellsâ€ Nano Lett., 14, 2584 (2014) 5. “Direct observation of dynamic symmetry breaking above room temperature in methylammonium lead iodide perovskite” ACS Energy Lett. 1, 880 (2016) Aron Walsh is a Royal Society University Research Fellow and Full Professor in the Department of Materials. Aron joined Imperial College London in October 2016. He was awarded his PhD in Chemistry from Trinity College Dublin. He then worked for the US Department of Energy at the National Renewable Energy Laboratory (NREL), followed by a Marie Curie Fellowship hosted at University College London, and a European Research Council Fellowship held at the University of Bath. His research involves cutting-edge materials theory and similation applied to problems across solid state chemistry and physics, including materials for solar cells and solar fuels, information storage, batteries, thermoelectrics and solid-state lighting. He has a particular expertise in the theory of semiconductors and dielectrics, and is developing innovative solutions for materials data, informatics and design. The Center For Excitonics Is An Energy Frontier Research Center Funded By The U.S. Department Of Energy, Office Of Science And Office Of Basic Energy Sciences LIGHT REFRESHMENTS WILL BE SERVED!

6 years, 5 months

[Aspuru-Guzik Group List] Talk by Postdoc Candidate Zhenpeng Yao (Today, 4 pm, Division Room)

by Daniel Tabor

Hi everyone, Today we have postdoc candidate Zhenpeng Yao from Northwestern giving a talk. His talk is at 4 pm in the division room. See the attachment for the title and abstract. Best, Danny

6 years, 5 months

[Aspuru-Guzik Group List] Excitonics/Perovskite Seminar: TODAY at 4:30 pm, RM 35-520

by Catherine M Bourgeois

TODAY AT 4:30! Center the Excitonics/Perovskite Seminar Series presents: Historic Overview and Design Principles for Optoelectronic Perovskite Materials* November 22, 2017 at 4:30pm/rm: 35-520 Michael Saliba École polytechnique fédérale de Lausanne (EPFL) Station 6, 1015 Lausanne [http://www.rle.mit.edu/excitonics/wp-content/uploads/2017/11/saliba_1.jpg] This presentation gives a general overview of the rapidly evolving field of perovskite solar cells (PSCs). Reasons why perovskite solar cells have triggered such enthusiastic feedback from research groups all over the world are discussed. The current challenges and approaches of the field are exemplified using a high-performance model systems for PSCs (a triple cesium (Cs), methylammonium (MA), formamidinium (FA) cation perovskite). The triple-cation composition achieves power conversion efficiencies (PCEs) close to 21% and stabilized power outputs at 18% under operational conditions over 250 hours (maximum power point tracking under full illumination held at room temperature). Adding Cs to MA/FA mixtures, which are currently among the highest performing compositions, suppresses yellow phase impurities and induces uniform perovskite grains extending from electron to hole collecting layer consistent with seed-assisted crystal growth. The triple cation perovskites are more robust to subtle variations during the fabrication process enabling a breakthrough in terms of reproducibility where PCEs > 20% were reached on a regular basis (in contrast to the MA/FA only devices). The principle of mixing cations can be taken further. Through multication engineering, the seemingly too small rubidium (Rb) can be integrated (despite never showing a black phase as a single-cation perovskite). The composition containing Rb, Cs, MA and FA results in a stabilized efficiency of 21.6% as well as an electroluminescence of 3.8%. The open-circuit voltage of 1.24 V at a band gap of 1.63 eV leads to one of the smallest losses-in-potential (of 0.39 V) ever measured for any PV material. Polymer-coated cells maintained 95% of their initial performance at 85°C for 500 hours under full solar illumination and maximum power point tracking. This is a crucial step towards industrialisation of PSCs. Dr. Michael Saliba is a Marie Curie Fellow at EPFL working with the Grätzel and Hagfeldt groups. He completed his Ph.D with Prof. Henry Snaith at Oxford University in 2014 working on crystallization behavior and plasmonic nanostructures in hybrid organic-inorganic perovskite thin films. He holds a BSc in mathematics and physics from Stuttgart University. His research focuses on a deeper understanding and improvement of optoelectronic properties of emerging photovoltaic technologies with an emphasis on perovskites for a sustainable energy future. In 2016, he was awarded the "Young Scientist Award" of the German University Association. In 2017, the MIT Technology Review named him as one of the World's "35 Innovators under 35". Light refreshments will be served *This talk is part of the Perovskites Seminar Series organized by Juan-Pablo Correa-Baena from MIT's PV Lab and sponsored by the Center for Excitonics. For more info contact Juan-Pablo: jpcorrea(a)mit.edu<mailto:jpcorrea@mit.edu> The Center for Excitonics is an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science and Office of Basic Energy Sciences

6 years, 5 months

[Aspuru-Guzik Group List] [qip] talk on Thursday Nov 30:Thomas Barthel- Efficient Simulation of 1d Q. systems

by Iman Marvian

Dear quanta, Thomas Barthel will be giving a seminar on Thursday, Nov 30th, at 2pm in Room 6C-442. Here is the title and abstract. ---------------------------------------------------- ---------------------------------------------------- Speaker: Thomas Barthel (Duke University) Date/time: Thursday Nov 30th, 2 PM Location: 6C-442 *Title: *Typical 1d quantum systems at finite temperatures can be simulated efficiently on classical computers *Abstract:* It is by now well-known that ground states of gapped one-dimensional (1d) quantum-many body systems with short-range interactions can be studied efficiently using classical computers and matrix product state techniques. A corresponding result for finite temperatures was missing. For 1d systems that can be described by an appropriate 1+1d field theory, I show that the cost for the classical simulation at finite temperatures grows in fact only polynomially with the inverse temperature and is system-size independent -- even for quantum critical systems. In particular, the thermofield double state (TDS), a purification of the equilibrium density operator, can be obtained efficiently in matrix-product form. The argument is based on the scaling behavior of Rényi entanglement entropies in the TDS. At finite temperatures, they obey the area law. For quantum critical, conformally invariant systems, the Rényi entropies are found to grow only logarithmically with inverse temperature. For gapped systems, they converge to a constant. The field-theoretical results are confirmed by quasi-exact numerical simulations for integrable and non-integrable spin systems, and interacting bosons. Ref: T. Barthel, arXiv:1708.09349 (2017) _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

6 years, 5 months

[Aspuru-Guzik Group List] Postdoc Candidate Zhenpeng Yao Visiting Monday November 27

by Daniel Tabor

Dear group, On Monday, November 27, Zhenpeng Yao will be visiting us. He is in the Wolverton group at Northwestern and has experience with materials screening, mostly with solid systems. Please let me know if you would like to meet with him on that day or if you would like to go out to lunch. He is interested in machine learning, so ML subgroup members should definitely try to sign up for a meeting if they are in town. Attached is the abstract for his talk, titled "Anionic redox reactivity and high-energy density cathode materials for Li-ion battery", which will be at *4 pm *in the *Division Room*. Cheers, Danny

6 years, 5 months

[Aspuru-Guzik Group List] Excitonics/Perovskite Seminar: Wed. Nov 22 at 4:30 pm, RM 35-520

by Catherine M Bourgeois

Please post and forward to your groups: Center the Excitonics/Perovskite Seminar Series presents: Historic Overview and Design Principles for Optoelectronic Perovskite Materials* November 22, 2017 at 4:30pm/rm: 35-520 Michael Saliba École polytechnique fédérale de Lausanne (EPFL) Station 6, 1015 Lausanne [http://www.rle.mit.edu/excitonics/wp-content/uploads/2017/11/saliba_1.jpg] This presentation gives a general overview of the rapidly evolving field of perovskite solar cells (PSCs). Reasons why perovskite solar cells have triggered such enthusiastic feedback from research groups all over the world are discussed. The current challenges and approaches of the field are exemplified using a high-performance model systems for PSCs (a triple cesium (Cs), methylammonium (MA), formamidinium (FA) cation perovskite). The triple-cation composition achieves power conversion efficiencies (PCEs) close to 21% and stabilized power outputs at 18% under operational conditions over 250 hours (maximum power point tracking under full illumination held at room temperature). Adding Cs to MA/FA mixtures, which are currently among the highest performing compositions, suppresses yellow phase impurities and induces uniform perovskite grains extending from electron to hole collecting layer consistent with seed-assisted crystal growth. The triple cation perovskites are more robust to subtle variations during the fabrication process enabling a breakthrough in terms of reproducibility where PCEs > 20% were reached on a regular basis (in contrast to the MA/FA only devices). The principle of mixing cations can be taken further. Through multication engineering, the seemingly too small rubidium (Rb) can be integrated (despite never showing a black phase as a single-cation perovskite). The composition containing Rb, Cs, MA and FA results in a stabilized efficiency of 21.6% as well as an electroluminescence of 3.8%. The open-circuit voltage of 1.24 V at a band gap of 1.63 eV leads to one of the smallest losses-in-potential (of 0.39 V) ever measured for any PV material. Polymer-coated cells maintained 95% of their initial performance at 85°C for 500 hours under full solar illumination and maximum power point tracking. This is a crucial step towards industrialisation of PSCs. Dr. Michael Saliba is a Marie Curie Fellow at EPFL working with the Grätzel and Hagfeldt groups. He completed his Ph.D with Prof. Henry Snaith at Oxford University in 2014 working on crystallization behavior and plasmonic nanostructures in hybrid organic-inorganic perovskite thin films. He holds a BSc in mathematics and physics from Stuttgart University. His research focuses on a deeper understanding and improvement of optoelectronic properties of emerging photovoltaic technologies with an emphasis on perovskites for a sustainable energy future. In 2016, he was awarded the "Young Scientist Award" of the German University Association. In 2017, the MIT Technology Review named him as one of the World's "35 Innovators under 35". Light refreshments will be served *This talk is part of the Perovskites Seminar Series organized by Juan-Pablo Correa-Baena from MIT's PV Lab and sponsored by the Center for Excitonics. For more info contact Juan-Pablo: jpcorrea(a)mit.edu<mailto:jpcorrea@mit.edu> The Center for Excitonics is an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science and Office of Basic Energy Sciences

6 years, 5 months

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aspuru-list November 2017