The resulting layer is so flexible that would be possible to layer it onto a soap bubble (although it will make the bubble wall much thicker, since a bubble wall is anywhere between 0.01 and 1 µm). As shown in the picture they actually embedded a solar cell into a soap bubble. Notice that it was not “printed” on the bubble, it was first printed and then included in the formation of the bubble by just placing it in the soapy liquid and blowing several bubbles till one got it embedded.
The solar cells is printed onto a polymer layer (PEDOT:PSS) and covered by the same polymer once printed. In addition it is sealed in a parylene coating (all this makes that first thin layer a bit thicker but it still remains very very thin).
It is clearly an amazing feat but what is more interesting is that it can have practical applications (not to power soap bubbles). The resulting solar cells have a low yield, 3.6% of actual conversion power (compare this with the best products you can buy today that have a 20% efficiency), but still can deliver a very high value of power in terms of weight, 6.3 W/g.
Such a thin layer can be used to cover a variety of objects, including smartphones and sensors. It has been shown to be water resistant for up to 6 hours and its flexibility makes it possible to fit the contour of any object. You may want to start with the table top in your garden. You cover it with these solar cells, a bit of electronics and an antsna and you can recharge your phones as you lay them on the table!
Another interesting field of application is bio-engineering. Such a thin film can cover implants (using a bio-compatible encasing layer) and skin grafts. It can also be used for robotic skin to power sensors.