22754
Self - assembly of conjugated 2 , 5 - dialkoxy - phenylene - thienylene - based oligomers on epitaxial monolayer graphene was studied in ultrahigh vacuum by low - temperature scanning tunneling microscopy ( STM ) .
 Chemical: 2 , 5 - dialkoxy - phenylene - thienylene; Chemical: graphene
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: 2 , 5 - dialkoxy - phenylene - thienylene, graphene 
Answer:
 Chemical: 2 , 5 - dialkoxy - phenylene - thienylene; Chemical: graphene