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The accurate determination of the work function of graphene is of significant importance to the engineering of graphene - based devices , and the measurement technique we have advanced in this Letter will have significant impact on numerous applications for emerging graphene - like 2 - dimensional material systems .
 Chemical: graphene; 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; Chemical: graphene