Storing the energy available from the sun as a fuel that can be used anytime is a major global challenge. Organic materials synthesised from abundant elements that can harness solar energy are being widely researched. Our approach is to use some of these materials (perylene bisimides) in a photo-electrochemical cell to split water into oxygen and hydrogen that can be stored as a gas and used whenever necessary. These materials are made using self-assembly to form gels that can either be used directly as wet materials or dried and re-hydrated for better stability. Using small angle neutron scattering we will investigate where and how well water is located in the gel and dried gel materials. Neutrons can detect the difference between water and heavy water, which we will exploit to obtain information about where the water is located when the gel is re-hydrated.