21019
Inverted CdSe / CdS / ZnS quantum dot light emitting devices with titanium dioxide as an electron - injection contact .
 CdSe, CdS, ZnS, titanium dioxide
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 CdSe, CdS, ZnS, titanium dioxide