Over many years of infrared photography I've never heard of other manufacturers producing special IR versions of photographic lenses. On the other hand, scientific suppliers such as Edmund Optics in the U.S. produce many lenses designed for particular wavebands including the near IR and shortwave IR. Caution is needed because many of these lenses are for small-format sensors and/or may only have enough resolution for machine vision uses. These lenses are not optimized for photography-as-art and may or may not give a pleasing rendition when used for that purpose.
Bill, Daniel's purpose is to find the partial failure of solar panels. Not for the IR art photography in which some of our folks here are interested.
Having said that, I mistakenly assumed that the sample image of the solar panel Daniel posted was a microscopic closeup. If the image was taken at a rather normal distance, chances could be that an older single-coated MF Nikkor would serve you.
I have no idea of the requirement of the image quality for your purpose, so this could be totally pointless. Nevertheless, there are some old MF Nikkors known to perform nicely without hot spot. I've used a single coated preAi Nikkor 28mm f3.5 used with an IR90 filter that cuts at 900nm.
The first image was shot with D2H and the second one, with D40. Both cameras were stock.