Migration of photogenerated charge carriers in silver halides: small polaron transport

TL;DR

This paper investigates the transport mechanism of photogenerated charge carriers in silver halides, providing evidence that small polarons, specifically Jahn-Teller polarons, are responsible for charge diffusion, advancing understanding of photodecomposition processes.

Contribution

It introduces the idea that small polarons, particularly Jahn-Teller polarons, are the primary charge carriers in silver halides, based on diffusion data analysis.

Findings

Diffusion data suggest small polaron formation.

Jahn-Teller distortions are involved in charge transport.

Supports the small polaron model for photocarrier mobility.

Abstract

Nearly half a century ago, I joined an ambitious research project aimed at establishing the mechanism of photodecomposition of ionic salts. We measured the mobilities and lifetimes of photoelectrons and photoholes in silver bromide in order to get an early-stage knowledge of the process. The last pairs of quantities to study were the diffusion coefficients for which we got results, highly controversial at that time. Now we show that the diffusion data suggest the formation of itinerant Jahn Teller small polarons as the next-stage photo-carriers in silver halides.