ADO.NET :: How To Find Record Between Specific Date

I m using ASP.NET and access as back end. I want to fatch a record between two specific date for that i

private void btnsearch_Click(object sender, EventArgs e)
{
cn.Open();
string str = "select Date1,Item,Rs,Payment from Books where Date1 BETWEEN '" + dateTimePicker1.Text + "' AND '" + dateTimePicker2.Text + "'";
cm = new System.Data.OleDb.OleDbCommand(str, cn);
System.Data.OleDb.OleDbDataReader r1;
r1 = cm.ExecuteReader();
while (r1.Read())
{
dataGridView1.Rows.Add();
dataGridView1.Rows[i].Cells[0].Value = r1[0].ToString();
dataGridView1.Rows[i].Cells[1].Value = r1[1].ToString();
dataGridView1.Rows[i].Cells[2].Value = r1[2].ToString();
dataGridView1.Rows[i].Cells[3].Value = r1[3].ToString();
i++;
}
cn.Close();
}

but it gives error Data type mismatch in criteria expression. table name is "book" fields are date1,item,rs,payment