The development of synthetic systems for the conversion of solar energy into chemical fuels is a
research goal that continues to attract growing interest owing to its potential to provide renewable and
storable energy in the form of a ‘solar fuel’. Dye-sensitised photocatalysis (DSP) with molecular catalysts
is a relatively new approach to convert sunlight into a fuel such as H2 and is based on the self-assembly
of a molecular dye and electrocatalyst on a semiconductor nanoparticle. DSP systems combine
advantages of both homogenous and heterogeneous photocatalysis, with the molecular components
providing an excellent platform for tuning activity and understanding performance at defined catalytic
sites, whereas the semiconductor bridge ensures favourable multi-electron transfer kinetics between
the dye and the fuel-forming electrocatalyst. In this tutorial review, strategies and challenges for the
assembly of functional molecular DSP systems and experimental techniques for their evaluation are
explained. Current understanding of the factors governing electron transfer across inorganic-molecular
interfaces is described and future directions and challenges for this field are outlined.