Split Chinese Character problem using tocharArray()

Question

I am writing a C# program to split Chinese Character input like this

textbox input ="大大大"
expected output =
大
大
大

And the code is like this

string aa="大大大";
foreach (char c in aa.ToCharArray()){
     Console.WriteLine(c);
}

It works fine for most of the characters. However, for some characters such as "𧜏", I got the result like this

textbox input = 𧜏大
output =
口
口
大

It looks like that the program fail to handle this character

Is there any solution to solve this?