Replications are available online, can't seem to spot any of the original material as of now. http://exo-science.com/phantomleaf.html (!!Woo-woo warning, just take what you need and exit stage!!).

Reverse search off above leads to "The Phantom Leaf Effect: A Replication, Part 1" "https://journals.sagepub.com/doi/abs/10.1089/acm.2013.0182". I have not had the time to examine the claims therein.