Solution Processing of Bismuth Telluride and its Alloys

Solution Processing of Bismuth Telluride and its Alloys

Solution Processing of Bismuth Telluride and its Alloys for Improving Thermoelectric Properties Zhongfen Ding Department of Chemistry and Biochemistry And Exotic Materials Institute University of California, Los Angeles Introduction Bismuth telluride and its alloys are currently the best thermoelectric materials known at room temperature and are therefore used for solid-state refrigeration. If the thermal electric figure of merit ZT could be improved by a factor of

about 3, quiet and rugged solid-state devices could replace conventional compressor based cooling systems. In order to test a theory that improved two dimensional materials could enhance ZT due to lower thermal conductivity, we are developing solution processing methods. These solutions could also be used to create microthermoelectric devices. Bismuth telluride and its p-type and n-type alloys have layered structures consisting of 5 atom thick Te-Bi-Te-Bi-Te sheets. Lithium ions are intercalated into the layered materials using liquid ammonia. The lithium-intercalated materials are then exfoliated in water to form colloidal suspensions. The layers are then deposited on substrates forming highly c-axis oriented thin films, which can be annealed at low temperatures. The exfoliated layers can potentially be restacked with other ions or layered materials in between the sheets to form

novel structures. The materials are characterized by powder X-ray diffraction, atomic force microscopy (AFM) and dynamic light scattering. Structure of Bi2Te 3 A b C A a b

C Te B C a A c B

A Te Te B c Te

Te Te Bi Bi Bi Bi Te Bi 2Te3 =

Te Te Bi Bi Li Intercalation Exfoliation

Li ion Solvated Li ion Exfoliation Molecular ions Flocculation Polymers Restacking Synthesis of LixBi2Te 3

Stopcock Liquid NH3 Li Bi2Te 3 Bi2Te 3 Li xBi2Te 3

Line Profile Measurements of Bismuth Selenide Deposited on Mica 160.0 120.0 80.0 40.0 0.0 0 0.4

0.8 1.2 m Height Profile [B] Height Profile [A] 20.0 20.0

10.0 10.0 0.0 0 0.1 0.2

0.3 m 0.0 0 20.0 20.0

10.0 10.0 0 0.1 0.2 0.2

0.3 Height Profile [D] Height Profile [C] 0.0 0.1 0.3 m

0.0 0 0.1 0.2 m 0.4 m Vegards Law Plot for Bi2Te3-xSex x 3

Bi2Se3 Nanowire

Recently Viewed Presentations

  • Parliamentary Procedure - Weebly

    Parliamentary Procedure - Weebly

    For a Moderated Caucus. Used for structured debate about more specific issues within topic; a "break" from the speaker's list. Delegate specifies purpose of caucus, length of caucus, and speaking time. Needs a simple majority to pass. During a moderated...
  • Manufacturing and Nanotechnology Group

    Manufacturing and Nanotechnology Group

    Professors. IoanMarinescu Precision Micro-machining and . Advanced Manufacturing. SaritBhaduri Biomaterials/Ceramics. Hongyan Zhang Welding and Material Joining. Ahalapitiya Jayatissa Thin Films, Nanotechnology, . MEMS. Mathew Franchetti Industrial Engineering. Yong Gan Energy materials
  • Comprehensive Jeopardy Review

    Comprehensive Jeopardy Review

    Category A 300 What is the half-way covenant? Category A 300 This economic practice during the colonial period promoted a favorable balance of trade (export $>import $)for the "mother" country. Category A 400 What is merchantilism? Category A 400 This...
  • PowerPoint-Präsentation - Vorwerk

    PowerPoint-Präsentation - Vorwerk

    Mit Vorwerk Thermomix lassen sich Speisen schneller und einfacher frisch zubereiten. So bringt der Thermomix viel Spaß beim Kochen von gesunden und geschmackvollen Gerichten.
  • Spelling is a tool for writing - Broken Bay Literacy Access Page

    Spelling is a tool for writing - Broken Bay Literacy Access Page

    Spelling is a tool for writing. Virginia Outred and Jane Denny (CSO) From David Hornsby lecture 4.6.12. ... 5 developmental stages of spelling. Stage. characteristics. Pre communicative. ... Spelling Activities only help students to contextualise strategies they do not specifically...
  • Purpose of Socratic Seminar - Pennsylvania State University

    Purpose of Socratic Seminar - Pennsylvania State University

    Closing Should connect student lives to text. Purpose of Socratic Seminar Provokes thought, dialogue, and ownership for learning Allows students to speak (97% of the time) Leads to self-knowledge and understanding Puts ownership of learning on students Gives students confidence...
  • Overview - Weebly

    Overview - Weebly

    Privately circle your level of agreement with the 8 statements. Mindset Survey. INTENT: Participants will become aware of their own Mindset. Refer to the handout, "Mindset Survey and Scoring Guide."
  • The Stefan-Boltzmann Law - Beverley High School

    The Stefan-Boltzmann Law - Beverley High School

    The Stefan-Boltzmann Law Calculating with Stefan's Law The Sun has surface temperature of 5800K. It's radius is 6.96 x 108m. Calculate its power output. ( the Stefan constant is 5.7 x 10-8 Wm-2K-4) Calculating with Stefan's Law A star has...