12537
Carbon nanotube - silicon solar cells are a recently investigated photovoltaic architecture with demonstrated high efficiencies .
 Chemical: Carbon; Chemical: silicon
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: Carbon, silicon 
Answer:
 Chemical: Carbon; Chemical: silicon