reading a string and converting to datetime

Hi All,
I have the following string
20140618:143357 I am trying to convert this to dateTime and I keep getting an error saying its not a valid datetime. Below is the way I am trying to convert it to dateTime:
DateTime.Parse(value.Value.Substring(0, 4) & "-" & value.Value.Substring(4, 2) & "-" & value.Value.Substring(6, 2) & " " & value.Value.Substring(9)) any help will be appreciated.