Yes, there is more solar energy available in the tropics because
(i) The sun’s rays are more concentrated there.
(ii) The sun’s rays have less atmosphere to pass through, so less energy is lost in absorption and reflection by the atmosphere.
(iii) Tropical rainforest area absorbs radiations due to presence of dense vegetation.
Availability of more solar energy in tropics contributes to higher productivity which in turn might contribute towards greater biodiversity.