You can totally use emojis as passwords. You can probably even make this a policy at your company.
Edit: I thought this was an obvious enough joke, but just to clear things up: Only do this if you hate your company and everyone working there.
And here I am avoiding even special characters because I worry about having to enter them on a French keyboard at some point.
I use only special characters that are on the same places with most layouts (at least english and finnish). I suppose passwords with ä or ö might be a bit more resistant to brute-force attacks, but it causes far more problems than it might theoretically solve.