Issue 7, 2019

When defects become ‘dynamic’: halide perovskites: a new window on materials?

Abstract

Although Pb Halide perovskites (HaPs) can be prepared as organic electronic materials, they resemble top-quality inorganic semiconductors, especially with respect to their low defect densities, as derived from optical and electronic transport studies. Among causes for such low defect densities were ‘defect-tolerance’ (proposed) and ‘self-healing’ (experimentally identified). We show that HaPs are likely an example of a class of materials that cannot support static bulk defect densities significantly above thermodynamically-dictated densities. The reasons are (a) the free energy to form HaPs (from binary halides) is less than the formation energies of (static) defects in them and (b) the small kinetic stabilization of such defects. We summarize the evidence for such a situation and conclude that higher defect densities in polycrystalline films likely result from the (expected) smaller defect formation energy at surfaces and grain boundaries than in the bulk. This situation directly limits the options for doping such materials, and leads to the counter-intuitive conclusion that a low free energy of formation (from the binaries) can lead to self-healing and, consequently, to low densities of static defects, to be distinguished from dynamic ones. The latter can be benign in terms of (opto)electronic performance, because of their relatively short lifetimes. We propose that the conditions that we formulated can serve as search criteria for other low defect density materials, which can be of interest and beneficial, also for applications beyond optoelectronics.

Graphical abstract: When defects become ‘dynamic’: halide perovskites: a new window on materials?

Supplementary files

Article information

Article type
Focus
Submitted
21 Сәу. 2019
Accepted
28 Мау. 2019
First published
28 Мау. 2019

Mater. Horiz., 2019,6, 1297-1305

When defects become ‘dynamic’: halide perovskites: a new window on materials?

Y. Rakita, I. Lubomirsky and D. Cahen, Mater. Horiz., 2019, 6, 1297 DOI: 10.1039/C9MH00606K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements