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Finally , we highlight the properties and advantages of single - , few - , and many - layer 2D materials in field - effect transistors , spin - and valley - tronics , thermoelectrics , and topological insulators , among many other applications .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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