Error in Laravel join

I am trying to get results from 2 table using join, where i want result between time range from those 2 tables,

here is my code

$final_trade = DB::table('finaltrade')
        ->join('exchanges', function($join)
        {
            $join->on('exchanges.id', '=', 'finaltrade.exchange_id')
                ->where('finaltrade.user_id', '=', Auth::user()->id)
                ->whereTime('finaltrade.created_at', '=', 'exchanges.start_time');
        })
        ->get();

when i add hardcoded time value instead of 'exchanges.start_time' it gives correct result but i want to add values from column,

via Chebli Mohamed