Advanced Materials Chemistry 2022-23
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Advanced Materials Chemistry 2022-23
Electronic Materials Assessment
*Upload coursework first to Turnitin for a plagiarism check and then to Gradescope for marking*
Introduction
The questions below are based on concepts you have learned from the lecture course and some parts require additional independent reading. If you wish to illustrate any of your answers using diagrams, you must draw them yourself (hand-drawn diagrams are also acceptable). Your answers should be submitted as a single PDF file, either hand-written or word processed.
Assessment
Part A – answer all parts.
1. Based on the publications listed in the bullet points below, comment on the potential application of the materials In2Se3 and InSe as the light-absorbing layer in a photovoltaic cell of structure shown in Figure 1, picking out and explaining only the information that is relevant. Your answer should be no more than 300 words. For this part, you will also be marked on the clarity, coherence and presentation (i.e. grammar and spelling) of your answer. [8]
Figure 1
• Synthesis of photo-responsive indium selenides (InSe and In2Se3 ) from tris(4,6- dimethyl-2-pyrimidylselenolato)indium(iii) as a molecular precursor, New J. Chem., 2022, 46, 3871
• Eco-friendly visible-wavelength photodetectors based on bandgap engineerable nanomaterials, J. Mater. Chem., 2011, 21, 17582
• First-principles investigation on electronic properties and band alignment of group III monochalcogenides, Scientific Reports, 2019, 9, 13289
calculate the Fermi Energy based on the free-electron model. [2]
3. Figure 2 shows an electronically delocalised molecule A, as well as an energy level diagram of its frontier orbitals including images of its LUMO, HOMO and HOMO-1 orbitals.
Figure 2: Left – Molecule A and Right – Frontier orbitals of Molecule A
(i) Based on the information in Figure 2, discuss whether Molecule A would be suitable to form the semiconductor in a near-infrared photodetector and explain your answer. [4]
(ii) Suggest a chemical modification to A that would make it a weaker electron donor and explain your answer. [2]
(iii) Suggest a chemical modification to A that would make it a weaker electron acceptor and explain your answer. [2]
(iv) Suggest a chemical modification to A that would make it more soluble in low-polarity solvents, without significantly altering its electronic properties. Explain your answer. [2]
Part B - Level 11 PGT students only should answer.
4. (i) For each of the following semiconductor materials, where x is a small number, identify whether its conductivity would be n-type, p-type or intrinsic and explain your answer. [4]
WS3-xSex Cu(Zn1-xSnx )S2 WO3-x Fx Cu2-xSe
5. (ii) Which of these semiconductors will have the largest bandgap. Explain your answer. [1]
2023-02-13