Abstract:
Three-(3D) and two-dimensional (2D) layered halide perovskites are highly promising candidates for optoelectronic applications, and this has sparked new investigations of these materials from the synthetic, physicochemical and applications point of view. The 3D versions of these compounds adopt the three-dimensional ABX3 perovskite structure, which consists of a network of corner-sharing BX6 octahedra, where the B atom is a divalent metal cation (typically Ge2+, Sn2+ or Pb2+) and X is a monovalent anion (typically Cl?, Br?, I?); the A cation is selected to balance the total charge and it can be a Cs+ or a small molecular species. Such perovskites afford several important features including excellent optical properties that are tunable by controlling the chemical compositions, they exhibit ambipolar charge transport with high mobilities. Another class of materials gaining significance are the two-dimensional (2D) perovskites -a blend of perovskites with layered crystal structure- (Ruddlesden-Popper type) offer a greater synthetic versatility and allow for more specialized device implementation due to the directional nature of the crystal structure. A remarkable advantage of the 2D perovskites is that their functionality can be easily tuned by incorporating a wide array of organic cations into the 2D framework, in contrast to the 3D analogues which have limited scope for structural engineering. We also present the new homologous series, (C(NH2)3)(CH3NH3)nPbnI3n+1 (n = 1, 2, 3), of layered 2D perovskites which is different from Ruddlesden-Popper type. Structural characterization by single-crystal X-ray diffraction reveals that these compounds adopt an unprecedented structure type which is stabilized by the alternating ordering of the guanidinium and methylammonium cations in the interlayer space (ACI). The these 2D perovskites combine structural characteristics from both Dion-Jacobson (DJ) and Ruddlesden-Popper (RP) structure archetypes. Compared to the more common Ruddlesden-Popper (RP) 2D perovskites, the perovskites we describe here have a different stacking motif and adopt a higher crystal symmetry.
 
Bio
Summary of Career: Since 2006 Charles E. and Emma H. Morrison Professor of Chemistry, NU. 2001/5: Distinguished Professor; 1997-2000 Distinguished in Chemistry, MSU. 1992: Full Professor of Chemistry 1990/7: Associate Professor of Chemistry, Michigan State University. 1987/91: Assistant Professor Michigan State University.
Publication Summary: No. of Papers: 1100 (h-Index=110), 51,000 citations, No. of Patents: 35
Honors/ Prizes / Awards / Medals: Presidential Young Investigator Award, National Science Foundation, 1989-1994; ACS Inorganic Chemistry Division Award, EXXON Faculty Fellowship in Solid State Chemistry, 1990; Beckman Young Investigator , 1992-1994; Alfred P. Sloan Fellow, 1991-1993; Camille and Henry Dreyfus Teacher Scholar, 1993-1998; Sigma Xi 2000 Senior Meritorious Faculty Award; John Simon Guggenheim Foundation Fellow, 2002; Alexander von Humboldt Prize, 2003; Morley Medal, American Chemical Society, Cleveland Section, 2003; Charles E. and Emma H. Morrison Professor, Northwestern University, 2006; MRS Fellow, Materials Research Society, 2010; AAAS Fellow, American Association for the Advancment of Science, 2012; Chetham Lecturer Award, University of California Santa Barbara, 2013; Einstein Professor, Chinese Academy of Sciences, 2014; International Thermoelectric Society Outstanding Achievement Award 2014; MRS Medal 2014; Royal Chemical Society DeGennes Prize 2015; Elected Fellow of the Royal Chemical Society 2015; ENI Award for the "Renewable Energy Prize" category; ACS Award in Inorganic Chemistry 2016; American Physical Society 2016 James C. McGroddy Prize for New Materials; APS Fellow 2016; Samson Prime Minister’s Prize for Innovation in Alternative Fuels for Transportation, 2016.
Service to the profession and synergistic activities: Editorial Advisory Board Inorganic Chemistry, 1994-1998; Editorial Advisory Board Chemistry of Materials, 1993-2000; Editorial Advisory Board J. of Alloys and Compounds; Editorial Advisory Board Z. für anorganische und allgemeine Chemie; Editorial Advisory Board Bulletin Korean Chemical Society 1998-; Editor-in-Chief: J. of Solid State Chemistry 1997-; Editorial Advisory Board Energy and Environmental Science 2012-; Editorial Advisory BoardJournal of Materials Chemistry A 2013-; Chairman Solid State Chemistry Subdivision, American Chemical Society 1998-1999; Organizer of Gordon Research Conference in Solid State Chemistry, 2008; American Chemical Society, Div. of Chemical Education, Examinations Institute Committee; 1996 and 2003 Inorganic Chemistry Committee; Co-organizer International Symposium on Advanced Nanoporous and Nanostructured Materials Heraklion, Crete, September 2016. Organizer of over 15 other international symposia in thermoelectric topics and inorganic materials topics.
PhD and Postdoctoral Students: >150 in total, 50 PhD Theses, >80 pursuing academic careers.