23059
The lifetime of dopant emission from transition - metal ion or lanthanide ion - doped QDs is generally longer than that of the bandgap or defect - related emission of host , and that of biological background fluorescence , providing great opportunities to eliminate background fluorescence for biosensing and bioimaging .
 Chemical: lanthanide
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: lanthanide