header('content-type:text/html; charset=utf-8');
echo urldecode('t%C3%BCrk%C3%A7e%20karakterler%20%C3%B6rn%3A%20%C3%B6%C3%A7%C5%9Fi%C4%9F%C3%BC%C4%B1');

echo urldecode(utf8_encode('t%C3%BCrk%C3%A7e%20karakterler%20%C3%B6rn%3A%20%C3%B6%C3%A7%C5%9Fi%C4%9F%C3%BC%C4%B1'));

türkçe karakterler örn: öçşiğüı