We use known colloidal chemistry methods to discover and make nanoscale crystals of new materials. By controlling the crystals composition shape and size we introduce quantum effects that change the material properties, such as increased light matter interactions through excitons and to drive impossible phase transitions. Large surface to volume ratio in nanomaterials naturally separates between surface and bulk processes, for example emphasizing the role of interfaces in charge transfer. These properties, position nanomaterials as an effective model system for the study of light matter interactions and charge extraction in existing and new materials, creating possibilities for the discovery of novel physical effects to face upcoming energy challenges.