Introduction

The urgency of increasing the use of renewable energy sources to feed our energy-intensive society sets the light (including solar) energy conversion among the most promising alternatives. The harvesting of the nearly-ubiquitous light in indoor environments is almost overlooked and it may contribute to a sustainable powering of the autonomous smart devices that are expected to be installed inside buildings in the coming years, as an alternative to or in combination with batteries, thus increasing their sustainability. The presented synthetic method provides access to a novel class of semiconductor nanomaterials that efficiently absorb indoor light and do not contain toxic elements, of capital importance due to the proximity with the end-users. In addition, our nanomaterials can also be used for manufacturing photoelectrodes, thus potentially opening new horizons for solar batteries and for artificial photosynthetic processes.

Technical features

Our process is based on the controlled nucleation and growth of the nanocrystals in the solution phase, which are prepared by the hot-co-injection of the anion precursors in a metal complex solution. Our method permits to fully explore the ternary metal-chalcogen-halogen phase diagram, providing access to a class of unexplored nanomaterials. Our synthetic method can be scaled up. Our materials do not contain toxic or scarce chemical elements. Our materials show high chemical stability (as opposed to, for example, lead halide perovskites) and superior light absorption properties. Our materials are dispersible in several media and can be used to formulate inks, pastes, and composites thus compatible with simple and cheap processing techniques (such as printing). Our materials can be processed into robust, conductive thin solid films capable of producing a stable current upon light irradiation.

Possible Applications

• Production of V-VI-VII semiconductor nanomaterials;
• Indoor photovoltaics;
• Photo(electro)chemical synthesis – artificial photosynthesis;
• Photo(electro)chemical storage – solar batteries.

Advantages

• High reliability of the process
• High versatility of the process
• Processability of the materials
• Rather reduced costs
• Scalability.