If you're interested in saving the planet while also making a profit, this app may be a good option for you.

As impact investing, also known as socially responsible investing, becomes more popular, financial experts say millennials seem to be drawn to funds that support the humanitarian or environmental missions they believe in. And the easiest way to do that may be with the click of a button on a device they use daily — their smartphone.

Some "socially conscious" portfolios use a set of 17 sustainable development goals as defined by the United Nations. The goals, according to the U.N., "address the global challenges we face, including those related to poverty, inequality, climate, environmental degradation, prosperity, and peace and justice."

Thanks to smartphones and social media, people now have information literally dropped into the palm of their hand. As a result, they are organizing more quickly and advocating for change, said Dave Fanger, CEO and founder of impact investing platform Swell. It's helping fuel a sense of purpose, he said, and makes people more proactive.

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A person may say, "I want to see a different world, and I can do something about it," Fanger added.

Why not bring that passion into finance?

Investing for impact isn't likely to diminish your financial returns, as CNBC has previously reported. Last year, sustainable funds outperformed a number of market benchmarks and most were in the top half of their categories, according to data from Morningstar.

And financial services firms such as Swell, Betterment and Acorns allow people to invest in some socially responsible companies.

At Swell, the hope is to pique people's interest at a young age, to get them thinking about moving money from a low-interest savings account into a market portfolio.