# There is plenty of room at the top: generation of hot charge carriers and their applications in perovskite and other semiconductor-based optoelectronic devices

## TL;DR

This paper reviews hot charge carriers in optoelectronic devices and strategies to improve their efficiency for future technologies.

## Contribution

The paper provides a comprehensive review of strategies to delay hot carrier cooling and enhance their extraction in semiconductor materials.

## Key findings

- Materials like perovskites exhibit slow cooling of hot charge carriers.
- Plasmonic nanostructures can enhance light coupling and optical absorption for generating hot carriers.
- Designing plasmonic structures enables tunable energy conversion of incident photons.

## Abstract

Hot charge carriers (HC) are photoexcited electrons and holes that exist in nonequilibrium high-energy states of photoactive materials. Prolonged cooling time and rapid extraction are the current challenges for the development of future innovative HC-based optoelectronic devices, such as HC solar cells (HCSCs), hot energy transistors (HETs), HC photocatalytic reactors, and lasing devices. Based on a thorough analysis of the basic mechanisms of HC generation, thermalization, and cooling dynamics, this review outlines the various possible strategies to delay the HC cooling as well as to speed up their extraction. Various materials with slow cooling behavior, including perovskites and other semiconductors, are thoroughly presented. In addition, the opportunities for the generation of plasmon-induced HC through surface plasmon resonance and their technological applications in hybrid nanostructures are discussed in detail. By judiciously designing the plasmonic nanostructures, the light coupling into the photoactive layer and its optical absorption can be greatly enhanced as well as the successful conversion of incident photons to HC with tunable energies can also be realized. Finally, the future outlook of HC in optoelectronics is highlighted which will provide great insight to the research community.

In photoactive materials, the fundamental understandings of hot charge carriers and a successful device design are the current challenges for the development of highly efficient hot carrier optoelectronic devices.