23610
For the PbSe QD / ZnO solar cells , where fewer intragap states are observed in the quantum dots , the interfacial recombination channel does not limit device performance .
 PbSe, ZnO
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 PbSe, ZnO