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.
Do be aware that a single emoji is often composed of multiple Unicode characters (e.g. base emoji + gender modifier + skin tone modifier). Entering that on the command line is going to be fun.