How can i get my gameobject as a sprite from its collider name?

i want to apply fade effect on my gameobject(in this case,the game object is sprite) only if i touched the object. Im confused how to cast my collider.name to gameobject(sprite)…I can detect the collider name but i cant apply fade effect on them because the parameter in my IEnumerator function is Spriterenderer…please help me

using UnityEngine;
using System.Collections;

public class Touch : MonoBehaviour
{
public SpriteRenderer sprite;

//Update is called once per frame
void Update ()
{
		if (Application.platform == RuntimePlatform.WindowsEditor) // Else if Desktop
		{ 
			if (Input.GetMouseButtonDown (0)) 
			{
				//StartCoroutine(Fade(/*what should i write here*/));
			rayCol();
			}
		}
	}

private void rayCol()
{
	Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
	RaycastHit hit = new RaycastHit();
	if(Input.GetMouseButtonDown(0))
	{
		if(Physics.Raycast(ray, out hit)) 
		{
			//what should i write here
			Debug.Log(hit.);
		}
	}

}

IEnumerator Fade(SpriteRenderer spriteName)
{
	for (float f = 1f; f > -0.01f; f -= 0.1f)
	{
		Color c = spriteName.material.color;
		c.a = f;
		spriteName.material.color = c;
		yield return null;
	}
}

}

Use GetComponent