Turning a monitor using Windows built-in commands is not possible even if you use Windows Azure Powershell commands. Instead I recommend to use a simple and powerful application which could be easily embedded into a .bat file. The one I am talking about is Wizmo. This handy application allows you to perform multiple maintenance operations regarding your Windows environment plus the physical devices you have. Download the application from the developer's page and save it to a simple location like C:\utility\. Here is a little script I wrote for you to help you turn off your monitor using this utility. Please be aware that your monitor support Windows advanced power management (APM) in order for the application to work.
Open a notepad and paste the following code and save the file as example.bat. Change C:\Utility\" with a path of yours where you saved the application. Make sure the folder in the root of a partition is named without spaces.
@echo off
C:\utility\wizmo.exe monoff
exit
