There are a couple issues to note:
DateTaken is a Windows properties, not a tag in a file. Windows fills the DateTaken value from a variety of tags.
PNG files do not support EXIF metadata. There is a non-standard way of inserting EXIF metadata but it isn't supported by Windows. You could copy
XMP:DateCreated, but Windows doesn't read XMP metadata from PNG files.
In the case of PNG files, Windows fills the DateTaken property from the
PNG:CreationTime tag. So you'll need to copy
PNG:CreationTime. You can do that with this command
exiftool -TagsFromFile SourceFile "-PNG:CreationTime<DateCreated" TargetFile
This is pretty much a special case for PNG files. Most other filetypes, Jpgs, Tiffs, RAW files, support EXIF metadata and you could use this command in those cases
exiftool -TagsFromFile SourceFile -DateCreated TargetFile
Actually, I suggest that you use either
CreateDate instead of
DateCreated is an IPTC legacy tag, is less likely to be in your file, and only holds the Date value and not the Time value.
CreateDate are EXIF tags that are much more likely to be in most files. PNG files still need to use PNG:CreationTime.