A recent study submitted to Acta Astronautica and currently available on the arXiv preprint server explores the potential for using aerographite solar sails for traveling to Mars and interstellar space, which could dramatically reduce both the time and fuel required for such missions.
While a promising line of research it should be noted that 26 day headline only applies to rapid delivery of small payloads (sub-kilogram) throughout the solar system.
Quote:
For the study, the researchers conducted simulations on how fast a solar sail made of aerographite with a mass up to 1 kilogram (2.2 pounds), including 720 grams of aerographite with a cross-sectional area of 104 square meters, could reach Mars
So, this is more about sending micro-satellites to the outer planets than it is about sending human or cargo missions..
The researchers note that one major question of using solar sails is deceleration, or slowing down, upon arriving at the destination, specifically Mars, and while they mention aerocapture as one solution, they admit this still requires further study.
It can't really be scaled up to human carrying capacity. The density of solar wind is very sparce. Any sail large enough to accelerate a human habitat would itself become too heavy.