17325
Using this approach the activation energy of the hole hopping transport within the undoped spiro - MeOTAD film was determined to be 0 . 34 +/- 0 . 02 and 0 . 40 +/- 0 . 02 eV for the mesoporous TiO2 and ZrO2 systems , respectively .
 Chemical: spiro - MeOTAD; Chemical: TiO2; Chemical: ZrO2
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: spiro - MeOTAD; Chemical: TiO2; Chemical: ZrO2