Try Screenbright, Display Tuner for brightness adjustment or try powershell script for brightness control
function Set-MonitorBrighness { [CmdletBinding()] param ( [ValidateRange(0,100)] [int]$brightness ) $mymonitor = Get-WmiObject -Namespace rootwmi -Class WmiMonitorBrightnessMethods $mymonitor.wmisetbrightness(5,$brightness) } Set-MonitorBrighness -brightness 1