The characters in 'Persian Letters' are often in situations that are both relatable and comical at the same time. They struggle with things like adapting to new environments, dealing with different social norms, and all these scenarios are presented in a humorous way that makes the novel stand out as a comic novel.
They might be used to create an exotic or alien feel. For instance, if the story is set on a planet with a civilization inspired by Persian culture, the letters could be part of their written language for everything from daily communication to scientific research.
Well, I'm not sure specifically which 'Persian letters' in science fiction are most notable. However, in general, science fiction often uses unique symbols or alphabets to create a sense of otherworldliness. It could be that in some Persian - inspired science - fiction settings, certain letters are used to denote alien languages or ancient scripts that hold the key to some mystery in the story.
You can start by choosing a unique font style that suits the comic's theme. Then, play with the size, boldness, and color to make the letters stand out.