Police say 20-year-old Andreas Acosta walked into the Bank of America branch on the 2800 block of Street Road in Bensalem and presented the teller with a demand note.
Acosta indicated that he was armed, by pulling up his shirt and displaying what appeared to be a gun.
Authorities later learned that the object was not a gun but a black cell phone.
Acosta was given an undisclosed amount of cash and fled to a nearby development.
The suspect was apprehended soon after and charged with robbery and related charges.