So, not really a spacesuit at all. Designed to work in planetary gravity, with an atmosphere surrounding it, even if the atmosphere is not optimum pressure and unbreathable or even corrosive. Their standard vacuum suits could be used as a temporary expedient, but carry a lot of gadgets that are unnecessary or ill adapted to the different conditions, notably propulsion.
If they in advance knew they would be exploring another planet, they'd take planetary isolation suits with them, sealed against external environments but otherwise very much like tough outside overalls with gloves and an airtight hood. Air can be carried, power recycled or filtered from the exterior atmosphere (anything that can detect molecular differences to get the gas mix right will have no problem eliminating viruses or potential allergens), but I doubt whether solar energy would be sufficient to do the carbon dioxide breakdown. There again it might be; plants are not over efficient.
You'd keep a slight positive pressure inflating the suit, so in the case of a puncture, interior gas would leak out, rather than unknown external compounds seeping in (with an alarm; it could always diffuse in). The most difficult is actually the gloves; difficult retaining strength and sensitivity without being perforable.
The exact requirements for the suit will depend on local conditions; a cold, thin-atmosphered desert planet would be essentially simple, just a question of insulation, not much different from terrestrial polar gear, while a thick, hot layer of methane, water vapour and carbon dioxide, though more promising for future terraforming, would demand refrigeration, and that pushes you towards the limit of what you what you can get from solar power. Odd that you should need more energy to get rid of heat than to generate it, and we've got to work out breathable air yet, too.
One trouble with solar power planetside is that you have to stock it. There are periods of darkness, obstacles to the energy. So you need some pretty hefty batteries of some sort – quite likely electrochemical, but perhaps magnetic or capacitive – incorporated into the weave. I can see several means of cooling – if you have an adequate supply of water you could even use your body's thermostasis sweat evaporation, pumped past the airtight (=waterproof) fabric of the suit by muscular action, if not (as in Dune), you need to run a gas compressor or heat intensifier semiconductor junction to generate coolth, and the energy used to run this will end up as more waste heat.
If you are in a cold environment, you can make the sunward side of the suit colour itself dark, absorbent, while the shadeward side is reflective, radiating as little energy as possible. This mode is compatible with absorbing as much solar energy as available. Inverting this for a hot environment means your solar energy conversion becomes low efficiency, practically useless (as you're reflecting off all the sunlight) even while you're needing more for your cooling system. I strongly suggest that a supplementary power generator be available for hot (or extremely cold) environments.
All this gas storage, energy storage, waste retention and insulation (plus protective armouring of the cloth - gotta be tough, long wearing, next best thing to indestructible) has made the thing thicker and clumsier than I had wanted; I'd hoped to make something you would hardly notice you had on, but it rapidly became clear this was not going to be the case. Lights, communications, ray guns, telemetry and other such power-hungry applications are not included, and will presumably be carried in a back pack. However, a moisture condenser is, and the suit's fabric acts as a radar beacon, lasing at a standard frequency.
), which are tight compression mesh which you can sweat through to use the body's natural thermostasis and water cooling rather than relying on heat radiators, we might be able to use entirely solar energy, but don't forget solar cells, like any heat engine rely on difference in temperature to function.
