Extended structure

19 Jan 2015

Spacegroup visualizer

Submitted by Barbara Reisner, James Madison University
Description: 

This looks like a great resource to visualize the data contained in the international tables in 3D.

My colleague, John GIlje, recommended this resource to me. It's not something I'll use on a day to day basis because it requires a PC.

Prerequisites: 
Course Level: 
Topics Covered: 
Corequisites: 
Learning Goals: 

I haven't used this in class, but saw a brief demo and it looks like a great way to help students visualize and interpret the international tables.

15 Sep 2014

Fe2GeS4 Nanocrystals for Photovoltaics

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Methods: 

My student led a 20-minute class discussion of this article in the spring of 2014.  The other students in the class were asked to post two questions about the article to moodle before the class meeting, but they were not asked to complete the literature discussion questions due to assignment overload at the end of the semester.

Evaluation Results: 

The six students posted good questions about the article, some of which I have incorporated into the literature discussion. One student asked why Ge was used instead of Si.  (My guess is that Si is too prone to oxidation - it's consistent with redox potentials.)  Another student wanted to know if any articles had been published after this one describing further progress.  At least two asked how the authors could determine that the photocurrent was p-type.

Description: 

I asked the students in my junior/senior inorganic course to develop their own literature discussion learning objects and lead the rest of the class in a discussion of their article.  Student Johann Maradiaga chose this article describing the synthesis and characterization of Fe2GeS4 nanocrystals with potential applications in photovoltaic devices (Sarah J. Fredrick and Amy L. Prieto, “Solution Synthesis and Reactivity of Colloidal Fe2GeS4: A Potential Candidate for Earth Abundant, Nanostructured Photovoltaics” J. Am. Chem. Soc. 2013, 135, 18256-18259. DOI: 10.1021/ja408333y).  The article describes the synthesis in hexadecylamine/octadecene of Fe2GeS4 nanoparticles and their characterization using powder X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, and photocurrent measurements.  Building on Johann’s original set of questions, I developed this literature discussion, which is suitable for use in inorganic chemistry courses. Many thanks to article author Sarah Fredrick for reviewing the assignment and adding some great questions.

Corequisites: 
Course Level: 
Learning Goals: 

After reading and discussing this paper, a student will be able to:

  • Understand how variable growth rates along different crystal planes result in specific shapes, and predict a resulting shape given a particular set of growth rates
  • Compare the oxidation behavior of Fe and Ge over time using XPS data
  • Describe a photocurrent measurement experiment and compare the photocurrent behavior of p-type and n-type semiconductors.
  • Explain the value of a communication as compared to a longer research article

 

Implementation Notes: 

Students do not need to be experts to understand this article, but previous exposure to solid state concepts including semiconductor electronic structure, solid state phases, nanoparticle synthesis, and capping agents will be helpful to them.  Alternatively, the article could be used to introduce these topics.

This JACS communication is fairly short and written clearly, so it could make a good first literature discussion for students without previous experience reading journal articles.

I have included a large number of possible questions in the literature assignment, but as always, users should feel free to pick and choose from the options and/or add their own.

Time Required: 
45 minutes (approximately)
12 Sep 2014

Maggie's LOs

Submitted by Chip Nataro, Lafayette College
Corequisites: 
Prerequisites: 
24 Jan 2014

Student choice literature-based take home exam question

Submitted by Hilary Eppley, DePauw University
Evaluation Methods: 

This question was 30 points on a 100 pt take home exam (the year I did this, there was also a 100 point in class exam as well).   I've included the title page of the take home exam as well as this question.   

The grading scale allowed most of the points for the student chosen course content to highlight.   Of the 30 points, 10 focus on chemical information skills, 20 on summarizing the article and analyzing it using concepts from the class.   

Evaluation Results: 

I gave back a number of the exams before I was able to tally, but of the ones I had remaining: 

60% got full credit on the part a (those who missed neglected to include a summary) 

100% got full credit on part b

60% got full credit on part c (those who missed searched by formula rather than connectivity or provided an insufficient explanation of what they searched on 

100% got full credit on part d

On part e, answers varied widely from 7/17 to 15/17, with an average of 12/17 or a 70%.  

In some cases they lost points for just repeating things verbatim from the paper without explaining them to show they understood the concepts.   The main reason for loss of points however was just a lack of effort at picking apart the paper for parts that were relevant to the course content.   

They were able to successfully apply things such as electron counting and mechanism identification in a catalytic cycle, point groups, descriptions of sigma and pi bonding in ligands.   

 

Description: 

During my junior/senior level inorganic course, we did several guided literature discussions over the course of the semester where the students read papers and answered a series of questions based on them (some from this site!).  As part of my take home final exam, I gave the students an open choice literature analysis question where they had the chance to integrate topics from the semester into their interpretation of a recent paper of their own choice from Inorganic Chemistry, this time with limited guidance.  I also included a number of questions that required them to make use of various literature search tools to show that they had mastered those skills.   I gave them a list of topics that they could incorporate, but based on the poor quality of the responses I received, I encourage you to be more specific in your instructions.  I'd love to see some new versions!      

Corequisites: 
Course Level: 
Prerequisites: 
Learning Goals: 
Students will
  • choose a recent paper that interests them from Inorganic Chemistry
  • summarize why a particular paper is important to the field of inorganic chemistry
  • use literature search tools including Web of Science, Cambridge Structural Database, and SciFinder Scholar to find information aobut cited references, structurally similar compounds, and the authors of the paper
  • integrate ideas such as bonding models, symmetry, spectroscopy structural data, and chemical reactivity from class into a detailed analysis of aspects of the paper

The instructor will

  • get up to date on new literature for possible new literature discussions
  • get a chance to stretch his/her own intellectual muscles on some papers perhaps outside of his/her area of expertise
Implementation Notes: 

The students were given the take home exam about 1 week before it was due (but that was during the final exam period).   The format of the chemical information questions were similar to things they did earlier in the class, however the analysis of the paper was much more open ended, giving them the freedom to choose a paper that interested them and to presumably focus on concepts from the class that they felt comfortable with.   I gave them a date range from April 1 - April 30, 2012 for their paper because those were the most recent issues at the time.  If you use this LO, you will probably want to change those dates to more recent ones.   

Time Required: 
at least an hour, possibly more depending on the student
7 Jan 2014

Solar-Powered Oxidation of Water

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Methods: 

I used this assignment in my half-credit nanomaterials chemistry course in the fall of 2013.  I graded the assignments on a 30-point scale, with all questions worth three points except for #1 (worth 7) and #4 (worth 8).

Evaluation Results: 

The average score on this assignment was 23.8 out of 30.  On the whole, the students found the article to be one of the most accessible of all the articles we read during the semester.

Description: 

Students in a half-credit nanomaterials chemistry course read an article describing the electrochemical deposition of BiVO4 (Kyoung-Shin Choi and Jason A. Seabold, “Efficient and Stable Photo-Oxidation of Water by a Bismuth Vanadate Photoanode Coupled with an Iron Oxyhydroxide Oxygen Evolution Catalyst” J. Am. Chem. Soc. 2012, 134, 2186-2192.  DOI: 10.1021/ja209001d).  The oxygen evolution driven by the bismuth vanadate was significantly enhanced by the addition of an iron oxide catalyst to the material’s surface.  This article is fairly easy to understand and can be used as an introduction to electrodeposition and photoelectrochemical cells.

Course Level: 
Prerequisites: 
Corequisites: 
Learning Goals: 

After reading and discussing this paper, a student will be able to:

  • Compare and contrast the experimental techniques used to gather the data presented in the article in terms of the type of information that can be obtained from each.
  • Describe the significance of this research in comparison to other types of materials used in the photo-oxidation of water
  • Describe the importance of solution pH in determining the feasibility of electrodepositing the BiVO4 material.
  • Outline the synthetic steps taken to achieve the final BiVO4 material and the FeOOH catalyst.
Implementation Notes: 

I used this assignment in my half-credit nanomaterials chemistry course in the fall of 2013.  The enrollment was seventeen students, including 14 chem majors, 2 biochem majors, and 1 physics major.  There were 4 seniors, 11 juniors, and 2 sophomores in the course.  Throughout the course, I assigned journal articles to read after we had done some introduction of the topic in lecture, but the assignments did not necessarily fall at the end of the topic.  Students brought their completed questions to lecture, handed them in, and then we discussed the article in detail as a class.  In this case, the students had already been introduced to solid state band structure using the “To Conduct or Not to Conduct” learning object in the previous week, when I had also introduced photovoltaics and the NREL solar efficiency graph.  In the lecture before this assignment was due, I explained that semiconductors can also be used to drive chemical reactions in photoelectrochemical cells.  I used TiO2 as an example of a photoanode and outlined the water splitting reaction.  We compared semiconductor band gap positions and water splitting redox potential positions.  I explained that even if these energies are aligned properly, a catalyst is often required. 

On the day the assignment was due, we reviewed the questions.  I created a chart on the board comparing the strengths and weaknesses of the different analysis techniques used in the article.  The students don’t have their assignments in front of them for this discussion, but they do hold onto their copy of the article, and their answers seem to be fresh in their minds.

Time Required: 
45 minutes
27 Jun 2013
Evaluation Methods: 

Written responses will be graded as well as an evalution of student participation in class discussion.

Evaluation Results: 

Evaluation results will be added after this learning object has been implemented in a course.

Description: 

This literature discussion activity is designed to highlight the use of different instrumentation and what details can be gained from each instrument.  It should also help the students review their knowledge of crystal structure, types of crystals, and amorphous solids.  The paper is from Chemistry of Materials, 2013, 25, 2394-2403 (DOI: 10.1021/cm303490y).  The paper should be given one week prior to class discussion, ideally after covering some of the instrumentation in class including X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). 

Corequisites: 
Prerequisites: 
Learning Goals: 

Students should be able to:

  • apply their knowledge of crystal structure, types of crystals, and amorphous solids to scientific literature.   
  • elucidate the hypothesis of a paper.
  • gain a greater understanding of the instrumentation used to determine the structural details of nanoparticles.    
Implementation Notes: 

Currently I am scheduled to teach inorganic chemistry every other year and have not yet taught the course.  I plan to use several literature papers throughout the course to introduce students to the current literature and relate the concepts to the course material we cover. 

Time Required: 
One class period
27 Jun 2013

Solid state, Semiconductors, Electrochemistry, and Nanowires for Solar Cells

Submitted by Jeremiah Duncan, Plymouth State University
Evaluation Methods: 

This learning object has not yet been tested.

Evaluation Results: 

This learning object has not yet been tested.

Description: 

This Literature Discussion learning object (LO) is based on the paper “Template Electrodeposition of Single-Phase p- and n-Type Copper Indium Diselenide (CuInSe2) Nanowire Arrays,” Emil A. Hernández-Pagán, Wei Wang, and Thomas E. Mallouk, ACS Nano, 2011, 5 (4), pp 3237–3241. DOI: 10.1021/nn200373k

This paper is about the synthesis and characterization of CuInSe2 nanowires using templates and electrodeposition. It is found that varying the potential of the electrodeposition influences the relative stoichiometry of the Cu and In atoms. Lower (more negative) potentials result in In-rich, n-type nanowires and higher potentials result in Cu-rich, p-type nanowires. These materials may find utility in solar cells, and nanowire geometry is predicted to result in more efficient solar-to-electrical conversion.

This paper covers topics in the following four categories: 1) electrochemistry, 2) nanomaterials, 3) semiconductors, and 4) solid state structures (including diffraction). Because these topics may be covered in different orders by different instructors, this LO has been designed to be modular to allow this Literature Discussion to occur at various points in the curriculum. Learning goals and relevant guiding questions have thus been grouped under each of these categories to help focus discussions. This LO may serve as a good review at the end of a course that covers all of these categories, though there is more here than can likely be covered in a single class. Therefore, it is assumed that, when implemented, instructors will choose to use individual learning goals/guiding questions or entire categories. Please implement and post any handouts or modifications that you create!

The creators of this learning object gratefully acknowlege Tom Mallouk (The Pennsylvania State University) for his contributions and insights to our group's discussions.

Prerequisites: 
Corequisites: 
Learning Goals: 

In reading this paper and participating in the literature discussion, students will:

Electrochemistry

  1. Calculate concentrations of electrolyte components based on stoichiometry.
  2. Rank elements in order of ease of reduction.
  3. Apply knowledge from the electrochemical series to understanding the synthesis of CuInSe2.
  4. Relate understanding of standard reduction potentials to topics in the current literature.

Nanomaterials

  1. Use TEM images to describe the dimensions of the synthesized nanowires.
  2. Describe a unique property of nanowires relative to the bulk material that may improve their utility in solar cells.
  3. Apply the relationship between grain size and peak broadening in XRD patterns using the Scherrer equation.

Semiconductors

  1. Define p-type and n-type semiconductors.
  2. Understand band diagrams for p-type and n-type semiconductors and for p-n junctions and use these to explain the unique properties of a p-n junction.
  3. Apply basic electron count process to predict doping type in extrinsic semiconductors.
  4. Distinguish the properties of direct and indirect band gap semiconductors.
  5. Describe quantitatively and qualitatively the relationships between semiconductor band gap energy and the absorption and reflection of visible light.
  6. Describe the four-probe method and distinguish between resistance and resistivity.

Solid state

  1. Understand ionic solid unit cells and how similar unit cells relate to each other:
    1. describe the zinc blende structure.
    2. describe the relationship of the zinc blende structure to the chalcopyrite structure.
    3. determine the coordination environments of atoms in the unit cell of chalcopyrite, specifically CuInSe2.
    4. understand the concept of solid solutions and how different ions can occupy the same lattice sites in an extended ionic solid.
  2. Define the nomenclature of Miller indices for lattice planes. Relate a particular set of Miller planes for a material to the unit cell and observed peaks in X-ray powder diffraction patterns.
  3. Calculate and interpret mole ratios from elemental analysis data.
27 Jun 2013

Tuning the band gap of CZT(S,Se) nanocrystals by anion substitution

Submitted by Benny Chan, The College of New Jersey
Evaluation Methods: 

We have not attempted to evaluate this LO.  As we use the LO, we will post the assessment data.

The writers of this LO also wanted to assess the effectiveness of the Concept Map LO of this article (Linked on website) when answering the same set of questions.  We want to assess whether concept mapping of the article would aid in the comprehension of a literature article.  If the students have a measureable increase in understanding, we believe concept mapping an article would be a good, transferable strategy for students to dissect and to understand an article.  

 

Description: 

The paper from the Prieto group, Riha, S. C.; Parkinson, B. A.; Prieto, A. L. J. Am. Chem. Soc. 2011, 133, 15272-15275, is proposed to be an excellent literature article for achieving several learning goals in the understanding of fundamental solid state and materials chemistry. The learning object was developed as a part of the 2013 VIPEr workshop and has not been tested in the classroom. We have developed a set of discussion questions that can be used as a guide for the students. We have also developed a complementary LO, that uses a concept map to help understand the article. We provide additional questions for assessing the concept map. We would appreciate help in testing the effectiveness of the discussion questions with and without the concept map.

The paper in discussion describes the synthesis of CZT(S, Se) nanoparticles that have potential application in the manufacturing of low-cost and environmentally responsible thin-film solar cells. The article reviews the previous literature and explicitly develops testable hypotheses. The as-synthesized nanoparticles are carefully studied by a suite of instrumental techniques including X-ray diffraction, high resolution transmission electron microscopy, and UV-vis spectroscopy. The data from the paper can be used to help students understand the synthesis, characterization, and properties of semiconducting nanomaterials. Furthermore, the paper explains the implications of their finding to further the scientific study of multicomponent chalcogenide nanocrystals.

Prerequisites: 
Corequisites: 
Learning Goals: 

LG1: Find a specific scholarly article and its supporting information from a library resource.

LG2: Explain the effects of solid solution formation on material properties including changes in the empirical formula, unit cell, lattice parameters, and energy band gap.

LG3: Compare multiple analytical techniques that are needed to complete a scientific study.

LG4: Use data to justify the goals of the article.

LG5: List the advantages and disadvantages of CZT(S,Se) nanoparticles as components in next generation photovoltaic devices.

LG6: Evaluate the usefulness of a concept map to connect multiple ideas in this primary literature article.

Implementation Notes: 

We have not attempted to implement this LO.  We imagine that this LO could be used in conjunction with the concept map LO.  We would assume that students could work in small groups to discuss the literature.

 

27 Jun 2013
Evaluation Methods: 

We have currently not evaluated this method.  We believe that this method could be generalized to examine any literature article.  As we test this LO, we will post our assessment data.

The related LO, Tuning the band gap of CZT(S,Se) nanocrystals by anion substitution, contains discussion questions on the article that can be used for additional evaluation.  We have also developed questions that we believe would use this concept map specifically.  We would enjoy comments on how these two related LOs are being used and assessing whether concept mapping helps students understand literature articles.

Description: 

Concept maps are a visual way to organize and represent information. In this literature discussion, we introduce a novel technique for teaching literature analysis to students where concept maps are used for establishing relationships between the key ideas, theories, procedures, and methods of a proposed literature article. Using the article “Compositionally Tunable Cu2ZnSn(S1-xSex)4 Nanocrystals: Probing the Effect of Se-Inclusion in Mixed Chalcogenide Thin Films” (Riha, S.C.; Parkinson, B.A.; Prieto, A.L. J. Am. Chem. Soc., 2011, 133, 15272-15275.) as a case study, students are asked to identify the key terminology related to the synthesis, properties, analysis, and application of semiconductor nanoparticles and are tasked to develop a concept map interrelating important conceptual ideas and results.

 

Learning Goals: 

LG1:  Identify key words that describe aspects synthesis, applications, properties, and analysis

LG2:  Create a concept map by identifying how the key words are related

Corequisites: 
Prerequisites: 
Implementation Notes: 

Supplies Needed:

- packs of sticky notes

- 3’x5’ poster paper or large sticky note pads

- markers

 

Before class

Students will be asked to read the paper before class and write down some key words and terms. There is an attached student handout to facilitate this process; this document briefly describes concept maps to students and gives three larger categories for students to begin grouping their key terms.

(The in-class activity may be implemented in a variety of ways to meet your classroom needs. Here we suggest a model conducive for small group work.)

In class

Begin with a class discussion about the terms or ideas that were found while reading the paper. As a group you might want to place these ideas into one of the three categories: synthesis, analysis, or properties. (Perhaps come up with several more at this point.) Students may then break into smaller groups and focus on one category (if you have a large class, you may choose to have multiple groups for each category). Provide each group with sticky notes and instruct them to write one term on each sticky note (a dry-erase board or large poster paper can also be used in place of sticky notes). They should begin constructing a concept map for this category. Ask students to consider the relationship between any concepts that are connected by lines and perhaps to write a short phrase that describes this relationship.

When these groups have developed the section of the concept map in some detail, bring the class back together to construct the larger concept map integrating the individual maps prepared by each group. Begin to think about the inter-connection of concepts within different categories.

There is a related learning object with discussion questions related to this paper, which may be used as a problem set for homework, guidance for discussion, or a wrap-up activity.

**NOTE** The goal of this learning object is to create a concept map for this article. One example of a concept map for this article has been provided in the instructors information. However, it must be noted that the map generated by your class will not necessarily be identical to the one that has been provided. It is expected that there will be variations between the different concept maps generated.

26 Jun 2013

Synthesis and Characterization of Magnetic Spinel Nanoparticles

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Methods: 

I have not used this literature discussion in its full form yet, but have used part of it as a final exam problem. 

Evaluation Results: 

On the spring 2013 final exam, a question based on these concepts was worth 22 points.  My students averaged 14.8/22, which was about the same as their average score on the entire exam.

Description: 

This learning object centers around an article published fairly early on in the history of nanoscience (Sun, et al. “Monodisperse MFe2O4 (M = Fe, Co, Mn) Nanoparticles” J. Am. Chem. Soc. 2004, 126, 273-279. http://dx.doi.org/doi:10.1021/ja0380852).  The article describes what has become a standard non-aqueous route to synthesize monodisperse spinel nanoparticles.  The assignment asks students to analyze the solid-state spinel structure, count 3d electrons for the various metal ions involved, and compare the particles' magnetic properties.  Students learn how to interpret a magnetic hysteresis loop and compare ferromagnetic and superparamagnetic behaviors.  

As written, this literature discussion is best for students who already have some familiarity with d-electron counting and solid state structures.  Anyone looking to extend the assignment could use the article to discuss X-ray diffraction, X-ray absorption, and nanoparticle ligand exchange.

Prerequisites: 
Corequisites: 
Learning Goals: 

After reading and discussing this paper, a student should be able to:

  • diagram the crystal packing of oxide ions and the coordination environment of metal ions in the spinel structure
  • identify the reducing agent and capping agents used in the synthesis of magnetic iron oxide spinel nanoparticles in organic solvents
  • compare the magnetization behavior of superparamagnets and ferromagnets
Implementation Notes: 

In the spring of 2011, I used this literature discussion in my junior/senior level inorganic course as part of reviewing for the final exam.  I also have used some of these concepts in an inorganic final exam question about the spinel structure and LFSE. 

The assignment assumes students already know how to diagram solid state structures using a "layer diagram" (e.g. z = 0, z = 1/2...).  Students should also be familiar with trends in the sizes of tetrahedral and octahedral holes in a solid state structure and trends in ionic radii.  Students do not necessarily need previous exposure to magnetism concepts.

In the final exam question (not included here), I ask students to calculate the LFSE (in terms of the octahedral splitting parameter) for each of the ions in the structure. (The individual LFSE's will vary based on d-electron count and the geometry of the surrounding oxide ions.)  One could also then introduce the concept of an "inverse spinel" in which the 2+ ion is in an octahedral hole and the 3+ ions are in octahedral and tetrahedral holes.  Students can sum up the total LFSE for each structure and predict which structure will be more energetically favored.

I do not have a completely satisfying answer for the last question on the literature discussion.  The answer centers around the concept of magnetic anisotropy.  If there is anyone in the VIPEr community who knows more about this than I do, please leave a comment.

 

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