This (XML-Only) Modlets adds two recipes to make solar panels and cells craftable within the workbench. Both items are locked behind the advanced engineering perk. For solar panels you'll need level four, while solar cells can be crafted after level 2. Quality will be depending on your perk level. Level 6 solar cells can still only be bought at traders.
To craft solar cells you will need broken glass, as there is no other glass material beside the bullet-proof glass block. Since it felt a bit "wrong" to use the bullet-proof glass block I've added another recipe to create broken glass inside the forge. Additionally you will need one acid bottle to make for more scarcity. The solar panel itself is crafted with regular materials (e.g. forged steel etc.) and steel- and robotics tools in order to increase scarcity.