Abstract

Persistent luminescent materials are compounds capable of temporarily storing sunlight in metastable traps and subsequently releasing it in the form of photons. Some of these materials can exhibit prolonged emission that may last for several hours. The DELPHI project aims to design persistent luminescent nanocrystals for use in converting sunlight within photovoltaic devices, with a view to overcoming their inherent discontinuity – that is, enabling them to operate even at night.

To overcome this challenge, the project aims to fabricate persistent luminescent nanocrystals through targeted synthesis strategies, designed to maximise sunlight absorption, increase storage capacity, control the duration of the phenomenon and achieve high emission. In particular, DELPHI proposes a new strategy in which the emission centre and the traps — that is, the two key factors for persistent luminescence — are located in two different materials. To this end, DELPHI will create nano-heterostructures to move the traps responsible for the phenomenon outside the material responsible for emission. This revolutionary strategy will make it possible to control the persistence of the emission at will, increasing both its intensity and duration.

The synthesis phase will be accompanied by an in-depth optical and structural investigation to confirm the beneficial effect of the heterostructure’s growth. The innovative nanocrystals will be used to assemble a prototype photovoltaic device capable of operating 24 hours a day. Overall, DELPHI aims to expand our understanding of the phenomenon of persistent luminescence, significantly improve the performance of nanoscale materials, and revolutionise photovoltaic devices and solar-powered technologies.