You started searching in the Phillips Library databases or even with a free search engine (like Google) and you retrieve 0 results.
You are writing a dissertation, you want your topic to be unique, so you hope nobody has written on your exact topic. How are you supposed to find resources on your topic AND find a unique topic to write about?
What aspects of your topic does have written research? Think about how research on each of the components of your topic would be valuable to your thesis. There may not be substantial research on your specific question, but there could be research on aspects of your topic.