Accentuating files in directory reading

I created a simple directory reading in PHP, but when I upload files with accents, they appear with strange characters and then I can not open those files.

How to correctly read the accent?

I've tried a lot of things changing to UTF8 in HTML, but so far nothing.

 <?php
    //diretorio
    $base = 'files/';
    $abreDir = ($_GET['dir'] != '' ? $_GET['dir'] : $base);
    $openDir = dir($abreDir);            
    //voltar
    $strrdir = strrpos(substr($abreDir,0,-1),'/');
    $voltar = substr($abreDir,0,$strrdir+1);

    $openDir = dir($abreDir);                 
       while($arq = $openDir -> read()):
            if($arq != '.' && $arq != '..'):
                if(is_dir($abreDir.$arq)):
                    //pastas                                                        
                    echo'<li class="folders"><a href="discovirtual?dir='.$abreDir.$arq.'/">'.$arq.'</a></li>';          
                else:
                    //arquivos     
                    echo'<li class="files"><a href="'.$abreDir.$arq.'">'.$arq.'</a></li>';                              
                endif;                      
            endif;              
       endwhile;
    if($abreDir != $base):
        echo '<a href="discovirtual?dir='. $voltar.'">Voltar</a>';
    endif;
    $openDir -> close();
?>