I've never met anyone touring who has successfully used solar to keep up with modern smart phones, they generally tend to use it to delay the inevitable, they still need to plug in sometimes (not saying you can't do it, just that I haven't met them). In order to get enough charge the panels need to be quite large as the robust panels are generally amorphous silicon, which is much less efficient. Then there is the security risk, solar panels are pretty attractive to thieves.
Hub dynamos will keep up with a smart phone in conjunction with something like a Forumslader that maximises output, for most touring but will struggle if the phone is doing something high drain, like being a WiFi hotspot.