Not to discourage you from trying to make this happen, but a bit of perspective might help. Currently android/java developers are in great demand, where I live the average salary is around $110,000/yr or roughly $2100/week. Having done a bit of contract/outsourcing work myself, I can tell you the experienced contractors/developers intended to lose as much as a weeks time on any project just trying to understand what needs to happen and working with the stake holders to make changes along the lines of "one more simple thing". The take away is there's going to be a minimum price/complexity to justify taking on a project for a skilled/competent developer and if your app doesn't meet that benchmark you're going to have hard time finding a U.S. based competent developer interested in it.
This doesn't mean it's a bad idea or you shouldn't do it, just keep in mind that while you may be really passionate about your idea to developers it's one of many offers to work on a contract for an individual offering below market rates. That's a great fit for contractors in India, students or a dev trying to expand her skill set (web dev still learning mobile apps, etc.) but not so appealing to established professionals.