Ion-icon not showing in my app

Hi all, in my app I try to use ion-icon in a list, item combination but it does not work and no icon appear with items. I tried to change icon for example from briefcase to home or something else but the problem still.
Here is the code:

Now the question is that: it need to install any module to activate ion-icon or there are any special configuration for it (perhaps)?
Thanks in advancedPreformatted text