Concussive Smite

The caster directs an explosive shockwave toward the target

The target hit by this attack takes 3d6 Force damage. The creature is forced to make a Strength saving throw. 

On a failed save, a shockwave propels them 10 feet backwards. This effect can stack with weapon or spell attacks that push (Weapon Mastery, Eldritch Blast etc).  If the target is pushed into a structure, it takes an additional 1d6 damage from the impact.

Using a Higher-Level Spell Slot. For every additional level the spell damage increases by 1d6.