I think the solar cells must be made from the highest efficeincy solar cells with the highest resistance against space radiation. The power supply of the vehicle must be of highest reliability to grantee the electricity supply for the it and its pay load. One has to choose the best space solar cells without compromise. So, i would use GaAs solar cells or single crystal silicon solar cells.
Polymer solar cells are not yet well approved solar cell technology and may suffer from the hard environmental effects in the space. I think they are not space qualified.
Yes it is. The GaAs solar cells and single crystal silicon solar cells are most suitable for work in an open space. However, these are very heavy structures and are unlikely they was used by the Chinese.
According to the information published about the Chinese rover, it weighs 140 kg. This is an appreciable weight. This is one thing. The second thing, it that not the silicon or Ga As wafers weight which makes out the weight of the solar cell modules. The encapsulation materials, are much heavier than solar cells themselves. As an example the glass superstrate and the metal frame. I think these materials are substituted with less weight material such as plexiglass instead of simple aluminum frame. Specially the planned mission lifetime is 3 months which is relatively short time.
For using organic solar cells, i think they till now are even not commercialized to be used for terrestrial applications.
Thanks for the answer. I asked why this question, because it is the Chinese who succeed in creating polymer solar cells. By the time the Yutu was launched, their efficiency was 12-15%. It's about publicly available sources of information.