29603
In this work , we report over 100 times modulation of light emission efficiency of these two - dimensional semiconductors by physical adsorption of O2 and / or H2O molecules , while inert gases do not cause such effect .
 Chemical: O2; Chemical: H2O
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: O2; Chemical: H2O