Yesterday, I discovered a new solar cell that has some benefits and drawbacks:

As you might be able to see, one of the benefits is that there are no lines on the top of the solar cell. This ties into the second benefit, which is that both the positive and negative connections are on the bottom of the cell. This greatly aides in turning this solar cell into a solar panel:

They're also very efficient -- partly because the entirety of the cell can absorb light energy -- with the panel in the first image acheiving 21.8% efficiency. I'd also imagine that, for a consumer DIY project, it would make Tetent look more professional since solder joints would be hidden on the back. There's also some 3.6W solar cells for a similar price but have visual defects:

I'm not sure the extra 0.3W is worth it over having to see a defect for the lifetime of the device. This 3.7W panel is the highest efficiency solar panel I've found in this size:

The main drawback for my application is that the smallest square is 125 x 125mm, and the solder pads are at the right edges of the cell, meaning that it can only be cut into 1/2 or 1/3 segments:

I will admit that, ergonomically speaking, the increased space would be more comfortable. Additionally, the larger the solar absorbing area, the more likely it would actually make a noticable difference to battery life, especially in sub-ideal lighting conditions; a 125mm panel would generate 56% more power than a 100mm one.

I'm just concerned because the final dimensions of Tetent would be sometihng like 190 x 190mm.

[25 Aug] This is a render with the panel: