Just to throw one more in...

https://youtu.be/ycFTxCoNAQk

Also, while I've known Big Clive to be a bit dismissive of the 'joule thief' concepts suitability in applications beyond that of momentary hobbyist flashlight fascinations, I think there may be merit in using a particularly beefy one with a massive smoothing-cap setup and a regulator of some basic sort, to power something like this. It would not be hard to cobble together a sort of 'doomsday supply' with such, along with a few scavenged solar panels, an old motorcycle battery or two, and a 'vibrator' regulator, to get a crude but effective power supply for a portable PC if the power demands were kept reasonable.

Hey, sorry for the long delay in response. I have looked into capacitor backups as well as for primary power supply- In my other project, a laptop is the goal and to lower the power consumption overall so much that a tiny 40mAh battery wouldn't be a terrible sin, but I totally see the benefit of not needing one- Jasper Sikken recently released a Lithium Ion Capacitor https://twitter.com/jrsikken/status/1367958907361107970 - seems useful in some instances where lots of power isn't constantly needed, but a battery would still be needed for most conventional laptops.

I kind of get the impression there's a language barrier at work here... there is no shame in Google Translate! The rest of this (including this sentence) is written in a style that I find helps with machine translators and eg eBay sellers that are somewhat challenged with their English, but won't use online translation tools... apologies, by the way, if I've misunderstood something there.

Regardless... what I was describing was more like this:

Extra-powerful "Joule Thief" circuit + smoothing capacitor (not for storage, but for noise and jitter) + boosted voltage regulator circuit.

For the "Joule Thief" circuit... I forget what they did with it, but I remember reading on the Hackaday Blog about a MOSFET-based variant that was unusually capable. While it could provide quite high current, given its nature, it was (as I recall) quite slow, even for a Joule Thief circuit! This was a few years ago...

Regarding the capacitor... look at very old power supplies for industrial equipment... power supplies from the 1960s and 1970s. Often they were little more than a transformer and two capacitors as large as ceramic mugs (!!) with screw terminals at the top. You probably won't need anything that big, but their spiritual successors (about the size of an energy drink can) will be your new friends here ;)

The usual method, for us hobbyists, with a need for a higher-current (a few amps, but not many - 3a to 5a at most) voltage regulator circuit, is to use a 78xx regulator (eg 7805, 7812) with a bipolar power transistor of roughly 2x the current rating needed. It seems to need to be twice the rating, although I'm not sure why -- all the designs I've seen consistently choose a transistor that is rated for approximately double the required output current -- and it absolutely *has* to be a bipolar power transistor for reasons that are extremely complicated and involve how the 78xx regulators work. I don't understand those things yet.

Minimal efficiency. "The purpose of this project is to simply brainstorm a variety of configurations, even ones that aren't even designed to produce power." 

My other project is designed for efficacy: https://hackaday.io/project/177716-the-open-source-autarkic-laptop

This LoFi project is more of a gallery for the other project- parts that haven't been tested yet to power a microcontroller, or have been tested and aren't capable of producing enough power. 

Some of these panels will be tested with two power managers that I will be receiving soon: a BQ25570-based manager:

https://www.powerfilmsolar.com/media/cms/Indoor_Solar_Development_Kit_LLDev1_083F9A3BC60A6.pdf 

and an AEM10941-based one. They are more likely to work with them, since the AM-1454CA has less than 4V open-circuit which is required. But it would most likely be wired in parallel with additional panels of the same model if is able to able to power the intended microcontroller. 

The other panels, like the AM-5412CAR, only works outside. It's not a current focus, and would most likely involve a different project which is more a of a hybrid laptop designed for quicker charging. The AM1816CA has an open circuit voltage of 4.9V and may not work with the BQ25570 or AEM10941.

Minimal or maximal efficiency? Or did you intend some other word like effectiveness or efficacy?