Perl to convert normal letter to wide character

How for perl to convert from halfwidth to fullwidth form? In perl's term, from normal character to wide character.

E.g., from !abc ABC! to ！ａｂｃ　ＡＢＣ！.Arithmetically, the following should be correct

binmode STDOUT, ":utf8";$letter = 'A';$lw = chr($letter + 0xfee0);print "Hello $lw ($letter)!\n";

But the print out is not what I was hoping for, which should be Hello Ａ (A)!