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Graphene functionalized with photo - active units has become one of the most exciting topics of research in the last few years , which remarkably sustains and expands the graphene boom .
 Chemical: Graphene; Chemical: graphene
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Graphene; Chemical: graphene