Photovoltaic cells and DSSCs answers
1. (a) Metals have relatively low ionization energies and their outer electrons are delocalized so can move freely as the metal conducts electricity. In non-metals the outer electrons are normally held in fixed positions forming covalent bonds between atoms so are unable to move. (b) Adding gallium (a group 13 element) causes a ‘hole’ in the silicon layer as it has one outer electron less than silicon. This ‘hole’...