DOCSLIB.ORG

The Path to Perovskite on Silicon PV

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Path to Perovskite on Silicon PV REVIEW https://doi.org/10.32386/scivpro.000004 The Path to Perovskite on Silicon PV Henry J. Snaith1*, Samuele Lilliu2 Henry J. Snaith is Professor of Physics in the Clarendon Laboratory at the University of Oxford and Fellow of the Royal Society. He has pioneered the field of perovskite solar cells and published more than 300 papers. He is the founder and Chief Scientist Officer of Oxford Photovoltaics, which holds the largest perovskite patent portfolio worldwide and focuses on developing and commercialising perovskite PV technology. In this interview, he discusses the present status and future prospects of perovskite PV. The interview is available at https://youtu.be/sbe9Z5oEs5o. Notable Achievements Samuele Lilliu (SL): How did you become one of the most influen- tial scientists in perovskite solar cell research and what have been the most notable achievements to date? Henry Snaith (HS): Perovskite solar cells are simply solar cells containing metal halide perovskites (Figure 1).1,2 I first became aware of metal halide perovskites in 2009, when visiting some colleagues and collaborators in Japan.1 The first paper using metal halide perovskites in solar cells had just been published by the group of Prof. Tsutomu (Tom) Miyasaka (Toin University of Yokohama, Japan).3 Tom gave a presentation on this work and it was very impressive. The most remarkable aspect was that he just took two salts, led bromide (PbBr2) and methylammonium bromide Figure 1 | Prof. Henry Snaith holding a 6 inch perovskite on Si wafer. (CH3NH3Br), put them together in a solvent, and spin coated a film, which crystallized immediately during spin coating.3 At the same time, back in Oxford, I would been playing around with quantum crystallizing the perovskite material, what we were getting was not dots led sulphide (PbS) nanoparticles.4 They were extremely tedious just small nano-crystals but more of a polycrystalline material, to synthetize and it took a long time, weeks of work, to make devic- with very long range crystalline order. We had a suspicion that we es. Whereas this perovskite material appeared to just form instantly. were also getting charge conduction in the perovskite material, so That was something that I found quite interesting. we made some test cells swapping out the porous TiO2, which is an 10 I subsequently returned to the UK and managed to get a collabo- electron conductor, with porous alumina (Al2O3). We tested these rative grant with one of my colleagues Takurou Murakami and I sent cells to see how they worked under the sunlight. We were not ex- a PhD student back to Japan to learn how to make these perovskite pecting highly functional solar cells because they had an insulator materials. Back in Oxford we managed to integrate them into what in place of one of the semiconductors, but surprisingly they actually 5-9 we were working on at the time: dye sensitized solar cells (DSSCs). worked better than the cells without TiO2 and we got a very big im- The device that Tom Miyasaka had developed3 was based on a po- provement in voltage.10 This was the first real breakthrough, where rous TiO2 anode, where the anode is sensitized, typically with a dye. we realized the perovskite material did not just act as a light absorb- He used small perovskite nano-crystals and then infiltrated the de- er but it also acted as a charge conductor in the cell.11 vice with an electrolyte.3 The big problem with this device was that Following on from that work, in close succession, we started in- the electrolyte dissolves the perovskite crystals, so the device lasted vestigating whether we really needed this porous alumina scaffold. seconds. I think this is probably one of the reasons why that work By making it thinner and thinner we improved current and device was not instantly followed. It looked like it was quite interesting, but efficiency at extracting charge.12 When we looked at a cross section just led to unstable cells. of these devices, they had a solid absorber layer of perovskite on top Whereas, in contrast, when we replaced the electrolyte with a of a thin porous scaffold of alumina.12 This told us already that the solid-state organic hole-conductor into the perovskite device, we solid perovskite material could conduct charge out of the device. obtained films that would be stable for a thousand hours under sun- Now that might not seem very surprising, but at the time the light, which was a massive step change. paradigm was that as a solid absorber material you could either have The big shock, if you like, or the first shock, was just our first a very expensive crystalline semiconductor with low defect density, batch of devices were already 6% power conversion efficiency. At or a cheap material that was easy to process from solution at low the time, DSSCs had hit a plateau of about 5% and for 3-5 years temperature, but with a lot of electronic disorder.13 The cheap ma- we could not get them any better. These perovskite devices were al- terials would not work as well as the expensive materials, and to ready more efficient on the first attempt and of course they rapidly get them to work you had to blend multiple materials, typically one stepped up. The first real surprise was that they worked instantly. material that would conduct electrons and one that would conduct Usually when trying a new material if you can get 1% efficiency you holes.14,15 In the case of the DSSC, the absorber was sandwiched are pretty happy. between these two materials in a rather complex meso-struc- Following on from that, with the way we were processing and tured or nano-structured device.16-20 The way of thinking was that 1*Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK. Contact Henry. J. Snaith. 2The UAE Centre for Crystallography, UAE SCIENTIFIC VIDEO PROTOCOLS | www.scivpro.com REVIEW SCIENTIFIC VIDEO PROTOCOLS materials either fell into a category of high disorder, but needed to be and the grain boundaries. nano-structured, or low disorder and would work in a solid crystal- The other component in the efficiency improvement, has been line film. The perovskites had the best of both worlds. They worked controlling the crystallization,34-37 working out good ways to process as a solid crystalline film and they were very easy to process at low these perovskite materials. temperature; so they were clearly in a different category, a league of The perovskite absorber itself in principle has a pretty low defect their own. density.38 There are not many defects and the defects that exist are Moving on from that, we demonstrated quite clearly that they not absolutely detrimental.39,40 They do not kill the performance, but could work as a solid thin film and in fact now the embodiment of limit the open circuit voltage.41 One way to improve the voltage is a perovskite solar cell is that on one side you have a charge selective to passivate the crystal. Here the term ‘passivation’ is used in a very material, maybe an n-type organic material, you have the perovskite broad term, because we do not really understand what is happen- absorber as a solid polycrystalline film (about 1 micron in thick- ing chemically. There are lots of routes of post-processing the films ness), then you have a p-type material (an organic charged conduc- that improve, for instance, the radiative efficiency and the fraction of tor or a metal oxide), and an electrode on the top. So it is a very sim- light re-emitted from the perovskite material.42-46 What we indicate ple sandwich structure device that we call a planar heterojunction or with the term ‘passivation’ could be recrystallization of the surface, double heterojunction.21,22 for example.47 Understanding the surface chemistry, the exact chem- Since those first few publications in the end of 2012, starting istry at the grain boundaries and in the buried interface is really im- from 2013, the research field of perovskite solar cells has absolutely portant, because this has in part driven the performance improve- exploded. To put it into context, in 2012 there were four publications ments.48 However, there is still a massive scope for further advances. on perovskite solar cells, in 2013 there were about sixty, last year in We are currently at 23% efficiency for record cells in labs, but actu- 2017 there were about 2,500, and this year there is probably going to ally there is nothing stopping us towards 30% efficiency in a single be 5,000 by the end of the year.23 Publications in the field are growing junction cell. That will happen by achieving better control of the sur- exponentially now. We were very fortunate to be there right at the face properties, in my view, of the perovskite absorber. beginning and we have managed to stay in the front pack, ahead Coupled with that, there has been a lot of tuning and optimiza- in certain aspects of the research. Obviously we have been lucky to tion of the contact materials.49,50 What is quite surprising is that we be riding this wave and hopefully we will be still riding this wave have not had to develop new contact materials. We just had to select through to fruition. So, the explosion of the field is the reason why materials that were already available either from the organic elec- we get so many citations for the work that we do.
Load more

Recommended publications
  • Nanosolar Is Leading the “Third Wave” of Solar Power Technology: the First
    Nanosolar is leading the “Third Wave” of solar power technology: ▪ The First Wave started with the introduction of silicon-wafer based solar cells over three decades ago. While ground-breaking, it is visible until today that this technology came out of a market environment with little concern for cost, capital efficiency, and the product cost / performance ratio. Despite continued incremental improvements, silicon-wafer cells have a built-in disadvantage of fundamentally high materials cost and poor capital efficiency. Because silicon does not absorb light very strongly, silicon wafer cells have to be very thick. And because wafers are fragile, their intricate handling complicates processing all the way up to the panel product. ▪ The Second Wave came about a decade ago with the arrival of the first commercial "thin-film" solar cells. This established that new solar cells based on a stack of layers 100 times thinner than silicon wafers can make a solar cell that is just as good. However, the first thin-film approaches were handicapped by two issues: 1. The cell's semiconductor was deposited using slow and expensive high-vacuum based processes because it was not known how to employ much simpler and higher-yield printing processes (and how to develop the required semiconductor ink). 2. The thin films were deposited directly onto glass as a substrate, eliminating the opportunity of ▪ using a conductive substrate directly as electrode (and thus avoiding bottom-electrode deposition cost), ▪ achieving a low-cost top electrode of high performance, ▪ employing the yield and performance advantages of individual cell matching & sorting, ▪ employing high-yield continuous roll-to-roll processing, and ▪ developing high-power high-current panels with lower balance-of-system cost.
    [Show full text]
  • New and Sustainable Photovoltaics
    New and Sustainable Photovoltaics The EPSRC Centre for Doctoral Training 2017 Review 2 The Centre for Doctoral Training New and Sustainable Photovoltaics 3 The EPSRC Centre for Doctoral Training in New and Sustainable Photovoltaics Contents All future energy forecasters agree on one thing: solar 03 - Director’s Foreword photovoltaics is now at the brink of mass adoption. But questions 04 - Partners remain. Where can the technology go from here? What’s in store 06 - How the Centre operates for the future of solar energy? The principal ambition of the 07 - The Cohort approach EPSRC Centre for Doctoral Training in New and Sustainable 08 - Research vision and key Photovoltaics, (known as CDT-PV), is to provide the future leaders themes who can answer these questions. Case Studies Led by the Universities of Liverpool and Bath, the Centre comprises seven leading academic institutions, the partners being Cambridge, Loughborough, 10 - SUPERGEN SuperSolar Hub 2[IRUG6KHIÀHOGDQG6RXWKDPSWRQ7KH&HQWUHLVDOVRVXSSRUWHGE\(LJKW Secondments LSA, NSG, Ossila, Oxford PV, M-Solv, Semimetrics and Silicon CPV. 11 - Research Cluster on We are training 60 of the best graduate students to guide PV in industry Perovskites and in universities. Students are registered for PhDs at each of the partner universities. In contrast to many CDTs, the research that will form their PhD 12 - Collaboration with a Large thesis is started at the beginning of the studentship. The principal skills Industrial Partner, NSG developed by our students are established by undertaking these projects. In 13 - Collaboration with a Small addition, each of our students undertakes a formal PV training course during WKHLUÀUVW\HDUYLVLWLQJHDFKRIWKHVHYHQSURJUDPPHQRGHVIRUWZRZHHNV Business, Ossila HDFK,QWKLVZD\WKH\GHYHORSQRWRQO\WKHVSHFLÀFNQRZOHGJHIRU39UHVHDUFK 14 - The CDT Student Community but experience the research environments of some of the UK’s leading 15 - Student Driven Training labs.
    [Show full text]
  • Blueprint Staff Magazine for the University of Oxford | September 2016
    blueprint Staff magazine for the University of Oxford | September 2016 Chemistry’s organic growth | Secrets of successful spelling | Oxford time News in brief u Oxford has topped the Times Higher research fellow at the college, set off at 6.30am Education World University Rankings for and arrived at Homerton, Harris Manchester’s 2016–17 – the first time in the 13-year history of twin college, in the afternoon. OxfordUniversity Images/Rob Judges the rankings that a UK institution has secured the top spot. The rankings judge research-intensive u The University’s phone system is being universities across five areas: teaching, research, replaced by a new service called Chorus. citations, international outlook and knowledge The service is being rolled out on a building- transfer. In total UK institutions took 91 of the by-building basis between autumn 2016 and 980 places, with the University of Cambridge spring 2018. Chorus will deliver replacement (fourth) and Imperial College London (eighth) phones together with access to a web portal, also making the top ten. which will provide additional functionality such as managing your voicemail, accessing u The University and local NHS partners have your call history, and sending and receiving won £126.5m to support medical research. instant messages. Details at https://projects.it. The money, from the National Institute for ox.ac.uk/icp. Health Research, includes £113.7m for the existing University of Oxford/Oxford University u The University has opened a new nursery Hospitals Biomedical Research Centre, and on the Old Road Campus in Headington, £12.8m for a new Biomedical Research Centre bringing the total number of University-owned specialising in mental health and dementia, nurseries to five.
    [Show full text]
  • Deciphering Photocarrier Dynamics for Tuneable High-Performance Perovskite-Organic Semiconductor Heterojunction Phototransistors
    Deciphering photocarrier dynamics for tuneable high-performance perovskite-organic semiconductor heterojunction phototransistors Item Type Article Authors Lin, Yen-Hung; Huang, Wentao; Pattanasattayavong, Pichaya; Lim, Jongchul; Li, Ruipeng; Sakai, Nobuya; Panidi, Julianna; Hong, Min Ji; Ma, Chun; Wei, Nini; Wehbe, Nimer; Fei, Zhuping; Heeney, Martin; Labram, John G.; Anthopoulos, Thomas D.; Snaith, Henry J. Citation Lin, Y.-H., Huang, W., Pattanasattayavong, P., Lim, J., Li, R., Sakai, N., … Snaith, H. J. (2019). Deciphering photocarrier dynamics for tuneable high-performance perovskite-organic semiconductor heterojunction phototransistors. Nature Communications, 10(1). doi:10.1038/s41467-019-12481-2 Eprint version Publisher's Version/PDF DOI 10.1038/s41467-019-12481-2 Publisher Springer Nature Journal Nature Communications Rights Archived with thanks to Nature Communications Download date 26/09/2021 06:46:47 Link to Item http://hdl.handle.net/10754/658584 ARTICLE There are amendments to this paper https://doi.org/10.1038/s41467-019-12481-2 OPEN Deciphering photocarrier dynamics for tuneable high-performance perovskite-organic semiconductor heterojunction phototransistors Yen-Hung Lin 1,10*, Wentao Huang2,10, Pichaya Pattanasattayavong 3, Jongchul Lim 1, Ruipeng Li4, Nobuya Sakai1, Julianna Panidi 2, Min Ji Hong5, Chun Ma6, Nini Wei7, Nimer Wehbe7, Zhuping Fei8,9, Martin Heeney 8, John G. Labram 5, Thomas D. Anthopoulos 6* & Henry J. Snaith 1* 1234567890():,; Looking beyond energy harvesting, metal-halide perovskites offer great opportunities to revolutionise large-area photodetection technologies due to their high absorption coeffi- cients, long diffusion lengths, low trap densities and simple processability. However, suc- cessful extraction of photocarriers from perovskites and their conversion to electrical signals remain challenging due to the interdependency of photogain and dark current density.
    [Show full text]
  • © Copyright 2017 Sarah M. Vorpahl
    © Copyright 2017 Sarah M. Vorpahl Correlating nanoscale optoelectronic and mechanical properties of solution processable thin film photovoltaic materials using scanning probe microscopy Sarah Marie Vorpahl A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Washington 2017 Reading Committee: David Ginger, Chair Brandi Cossairt Xiaosong Li Program Authorized to Offer Degree: Chemistry University of Washington Abstract Correlating nanoscale optoelectronic and mechanical properties of solution processable thin film photovoltaic materials using scanning probe microscopy Sarah Marie Vorpahl Chair of the Supervisory Committee: Professor David S. Ginger Chemistry Solution processable materials present a competitive alternative to traditional silicon solar cells based on inexpensive processing and flexible form factors. Several competing technologies have entered the market in the past few years, including cadmium telluride and copper, indium, gallium, sulfur (CIGS) alloys. In addition to this nascent commercialized product, several emerging technologies also offer promising alternatives. Copper, zinc, tin, sulfur (CZTS) kesterite materials offers an earth abundant option, moving away from more price volatile minerals such as the indium used in CIGS. Hybrid perovskites (HPs) have been revealed as one of the most exciting new solution processable materials, with efficiency improving exponentially in just the past several years. This dissertation explores the underlying electrical
    [Show full text]
  • How Founders Use External Advice to Improve Their Firm's Chance of Succeeding
    The dynamics of forming a technology based start-up: How founders use external advice to improve their firm's chance of succeeding by Nick Cravalho B.S. Mechanical Engineering University of California, Berkeley, 2000 Submitted to the System Design and Management Program in Partial Fulfillment of the Requirements for the Degree of Master of Science in Engineering and Management at the Massachusetts Institute of Technology May 2007 2007 Nick Cravalho. All rights reserved The author hereby grants to MIT permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part in any medium not known or hereafter created. Signature of Author Nick Cravalho System Design and Management Program May 2007 Certified by Diane Burton Thesis Supervisor Sloan School of Management Certified by _ Patrick Hale Director OASSACHUSETTS INS System Design and Management Program OF TECHNOLOGY FEB 0 1 2008 BARKER LIBRARIES The dynamics of forming a technology based start-up: How founders use external advice to improve their firm's chance of succeeding by Nick Cravalho Submitted to the System Design and Management Program on May 11, 2007 in Partial Fulfillment of the Requirements for the Degree of Master of Science in Engineering and Management Abstract External advice can be a valuable resource for founders of high technology startup companies. As with any resource, the pursuit and efficient use of the external advice resource is one of the greatest challenges for founders. This thesis examines how the founders of eleven US venture-backed high-tech companies leveraged external advice to their advantage.
    [Show full text]
  • Solar Energy: a New Day Dawning?: Silicon Valley Sunrise Oliver Morton Oliver Morton Is Nature's Chief News and Features Editor
    Solar energy: A new day dawning?: Silicon Valley sunrise Oliver Morton Oliver Morton is Nature's chief news and features editor. Abstract Sunlight is a ubiquitous form of energy, but not as yet an economic one. In the first of two features, Oliver Morton looks at how interest in photovoltaic research is heating up in California's Silicon Valley. In the second, Carina Dennis talks to Australian researchers hoping to harness the dawn Sun's heat. The Sun provides Earth with as much energy every hour as human civilization uses every year. If you are a solar­energy enthusiast, that says it all. No other energy supply could conceivably be as plentiful as the 120,000 terawatts the Sun provides ceaselessly and unbidden. If the tiniest fraction of that sunlight were to be captured by photovoltaic cells that turn it straight into electricity, there would be no need to emit any greenhouse gases from any power plant. Thanks to green thoughts like that, and to generous subsidies from governments in Japan and Germany, the solar­cell market has been growing on average by a heady 31% a year for the past decade (see chart, below). One of the most bullish industry analysts, Michael Rogol, sees the industry increasing from about US$12 billion in 2005 to as much as $70 billion in 2010. Although not everyone predicts such impressive growth, a 20–25% annual rise is widely expected. The market for shares in solar­energy companies is correspondingly buoyant. And yet in the projections of energy supply made by policy analysts and climate wonks, solar remains so marginal as to be barely on the map at all.
    [Show full text]
  • Solar PV Technology Development Report 2020
    EUR 30504 EN This publication is a Technical report by the Joint Research Centre (JRC), the European Commission’s science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication. For information on the methodology and quality underlying the data used in this publication for which the source is neither Eurostat nor other Commission services, users should contact the referenced source. The designations employed and the presentation of material on the maps do not imply the expression of any opinion whatsoever on the part of the European Union concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Contact information Name: Nigel TAYLOR Address: European Commission, Joint Research Centre, Ispra, Italy Email: [email protected] Name: Maria GETSIOU Address: European Commission DG Research and Innovation, Brussels, Belgium Email: [email protected] EU Science Hub https://ec.europa.eu/jrc JRC123157 EUR 30504 EN ISSN 2600-0466 PDF ISBN 978-92-76-27274-8 doi:10.2760/827685 ISSN 1831-9424 (online collection) ISSN 2600-0458 Print ISBN 978-92-76-27275-5 doi:10.2760/215293 ISSN 1018-5593 (print collection) Luxembourg: Publications Office of the European Union, 2020 © European Union, 2020 The reuse policy of the European Commission is implemented by the Commission Decision 2011/833/EU of 12 December 2011 on the reuse of Commission documents (OJ L 330, 14.12.2011, p.
    [Show full text]
  • Nanosolar & U.S. Department of Energy Solar America Initiative
    Securing our Energy Independence and Sustaining our Environment March 2011 1 Our High-Speed Solar Cell and Panel Factories Can Be Built Cost Effectively Anywhere in the World We Do Not Need to Manufacture in Asia to Be Competitive: We can build in San Jose! San Jose, California, Global Headquarters & Solar Cell Production Factory, 200,000 sq ft Luckenwalde, Germany, Panel Assembly Factory, 500,000 sq ft 2 We Print Nanotechnology-enabled Ink on Rolls of Very Inexpensive Aluminum Foil Rapid processing using low cost equipment and the lowest cost metal substrate 3 Our Flexible Foil Cells Are Built in San Jose, CA . Rolls of printed foil processed and thin film layers added to complete electrical structure . Foil cut into individual, rectangular cells . Flexibility to tune cells’ power output for Utility, Commercial and Residential solar markets 4 We then Assemble these Cells into Utility-scale Panels . 84 cells welded together to form one solar panel . Cells sandwiched between two tempered glass plates . Glass plate edges sealed to protect against weather Specifically designed from the start to make Nanosolar utility-scale solar power plants competitive with fossil fuels 5 Nanosolar Power Plants Are Built in Municipal Areas Connection to Distribution Voltage Lowers Delivery Costs Nanosolar power plants can be constructed on landfills, brown fields and green fields, as well as on flat rooftops 6 Nanosolar CA Factory Expansion Can Create Thousands of Skilled Solar Jobs Each Year For every 100 MW of production: . Navigant: 1,000 downstream jobs in system integration, installation, and O&M . Deutsche Bank : 3,700 downstream jobs in system integration, installation, and O&M .
    [Show full text]
  • July 2015 IEEE EDS Newsletter
    JULY 2015 VOL. 22, NO. 3 ISSN: 1074 1879 EDITOR-IN-CHIEF: M.K. RADHAKRISHNAN TABLE OF CONTENTS TECHNICAL BRIEFS . 1 T ECHNICAL B RIEFS • Reliability Trends of Nano-scaled CMOS Devices • Report on 2015 IEEE International Reliability Physics Symposium • Wide Bandgap Semiconductors, They’re Special RELIABILITY TRENDS OF UPCOMING TECHNICAL MEETINGS . 10 • 2015 IEEE International Integrated Reliability NANO-SCALED CMOS DEVICES Workshop (IIRW) • 2015 IEEE Compound Semiconductor IC GUIDO GROESENEKEN Symposium (CSICS) IMEC AND KU LEUVEN, BELGIUM • 2015 IEEE Bipolar/BiCMOS Circuits and Technology Meeting (BCTM) SOCIETY NEWS . 13 With the continuous downscaling of CMOS technologies, reliability • EDS Vision and Mission Statements is more and more becoming a major bottleneck and this for several • EDS President’s Message reasons. First of all the electric fields and current and power densi- • Message from EDS Vice President of Regions/ Chapters ties have increased continuously and are now reaching the maxi- • Message from Newsletter Editor-in-Chief mum values that can be allowed for reliable operation. At the same • EDS Governance Meeting Summary time an impressive effort is taking place introducing new materi- • Call for EDS Board of Governors Nominations • EDS Board of Governors Election Process als and novel device architectures to maintain the effective perfor- • IEEE Election Reminder mance scaling. New materials like high k dielectrics and metal gates • EDS Compound Semiconductor Devices and for both logic and memory technologies and novel device concepts Circuits Technical Committee Report • 2015 William R. Cherry Award Winner such as Multiple gate FET’s have already been introduced, while Ge • 42nd Photovoltaic Specialists Conference (PVSC) or III-V materials for high mobility devices are under investigation.
    [Show full text]
  • Structure Prediction, Growth, and Characterization of Perovskites
    STRUCTURE PREDICTION, GROWTH, AND CHARACTERIZATION OF PEROVSKITES A Dissertation Presented to the Faculty of the Graduate School of Cornell University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by Eva Helena Smith August 2017 c 2017 Eva Helena Smith ALL RIGHTS RESERVED STRUCTURE PREDICTION, GROWTH, AND CHARACTERIZATION OF PEROVSKITES Eva Helena Smith, Ph.D. Cornell University 2017 The heart of materials science is understanding the relationship between structure (how molecules are connected at the atomic level, as well as in hierarchical building blocks) and properties. Historically this has been achieved by studying the properties of materials in hand, either found in nature or synthesized in the laboratory. As the understanding of the relationship between structure and properties has grown, and our ability to calculate and in particular to solve Schrodinger’s¨ equation for solids has improved, so too has our desire and ability to predict structures with enhanced properties through computation. In this thesis I do each of those three tasks – prediction, synthesis, and characterization – on a system that is of interest in its own right and which I hope may yield results that can be applied to other materials systems as well. All of these systems are materials in the highly-versatile perovskite structure, which can accommodate most of the elements of the periodic table. Perovskites have been the object of much study in the laboratory as well as being used extensively in industrial applications, with such properties as ferroelectricity, piezoelectricity, ferromagnetism, and superconductivity. First, I delineate the chemical factors that determine the ground-state structure of CsPbF3.
    [Show full text]
  • Ch3nh3pbbr3 Perovskite Solar Cells for Tandem Application – Demonstrations and Characterizations Rui Sheng
    CH3NH3PbBr3 Perovskite Solar Cells for Tandem Application – Demonstrations and Characterizations Rui Sheng A THESIS IN FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY School of Photovoltaic and Renewable Energy Engineering Faculty of Engineering The University of New South Wales March 2017 1 Supervisor Dr. Anita Ho-Baillie*, Prof. Martin Green* Co-supervisor Dr. Shujuan Huang*, Dr. Xiaojing Hao* * School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, Australi 2 THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: SHENG First name: RUI Other name/s: Abbreviation fordegree as given in the University calendar: Ph.D School: SCHOOL OF PHOTOVOLTAIC AND Faculty: ENG [NEERING RENEWABLE ENERGY ENGINEERING Title: CH3NH3Pb8r3 PEROVSKITE SOLAR CELLS FOR TANDEM APPLICATION - DEMONSTRATIONS AND CHARACTERZA TIONS Abstract 350 words maximum: Perovskite solar cells based on organometal halides have experienced an unprecedentedly rapid development since 2012, when the first efficient perovskite-based solar device with solid-state structure was reported. Increasing amount of research interests are focusing on characterizing material properties, developing deposition methods, resolving the instability and toxicity, as well as designing tandem structure. This thesis will present a comprehensive study of CH3NH3PbBr3 perovskite-based solar cell, including a novel deposition method for high efficiency CH3NH3Pb8r3 solar cells, which shows substantial improvement over conventional one-step solution process, not only in the power conversion efficiency (1.7% vs 9.1 %), but also in hysteresis. In the material characterization section, a study using one-photon and two-photon microscopy was conducted to reveal additional insight in the understanding of grain formation and carrier extraction.
    [Show full text]