You sure can. Peppers and Tomatoes are probably the only vegetables that I can think of that I do freeze without blanching them first. Just remember that they will be no good in salads as they become soft. I usually cut them the way I want them and freeze them on a tray in the freezer. After they are frozen I throw them into a freezer bag and only have to take out what I need
when I use them because they are not stuck together.