Trying to make object turn red OnTriggerEnter

I am trying to make a cube where if an object with powered tag collides with trigger collider of the cube it turns red and gets powered tag. If no powered tag objects are touching it it should be gray and unpowered. Unity does not return an error but it doesn't do anything regardless.

 void OnTriggerEnter(Collision collision)
 {
     if (collision.rigidbody.tag == "powered")
     {
         this.tag = "powered";
         this.GetComponent<Material>().SetColor("_Color", Color.red);
     }
     else
     {
         this.tag = "unpowered";
         this.GetComponent<Material>().SetColor("_Color", Color.gray);
     }
 }