The Complex Interplay of Lead Halide Perovskites with Their Surroundings

Abstract

Photoexcitation of lead halide perovskites induces a restructuration of the material that simultaneously enhances its emission properties and triggers its degradation. These concomitant processes are strongly dependent on the surroundings of the perovskite, both while and after being processed, underlining the relevance the environment and the interfacial design have in the stability and performance of these materials and the devices based on them. This shocking observation reveals that when subjected to external illumination, lead halide perovskites undergo a number of photophysical processes that strongly modify their structure and thus their optoelectronic properties. Such photoinduced instability stems from a defective structure directly linked to the low‐temperature and solution‐processed fabrication routes generally employed to build perovskite solar cells with efficiencies comparable to state‐of‐the‐art values. On the other hand, these same inexpensive and unsophisticated procedures make this material a promising component in energy conversion devices. Here, an analysis is provided regarding the different impact on the perovskite structure, hence on its optoelectronic performance, that the interaction with its surroundings has, providing specific examples that highlight this interplay, describing the kind of modification it induces, and listing the related effects on the optoelectronic properties that should be accounted for when characterizing them.

Optoelectronic Devices Based on Scaffold Stabilized Black‐Phase CsPbI3Nanocrystals

“…The precursor ratio has an impact not only on crystal size, which can be explained by the different nucleation and precipitation rates occurring under excess or lack of one of the reagents, but also on the quality (i.e., defect density) of the crystals. The relation between the stoichiometry and the surface chemistry of the bulk perovskite grains have been reported in previous studies, [32][33][34] which propose that crystals with less defect density are attained due to the selfpassivation produced by the CsIrich media in the solution precursor. This has been demonstrated to be crucial in the stabilization of CsPbI 3 opti cally active phases, since the (100) surface with CsI termination of the alpha phase shows the lowest Gibbs free energy.…”

New Approach toward Dual-Emissive Organic–Inorganic Hybrids by Integrating Mn(II) and Cu(I) Emission Centers in Ionic Crystals

“…It should be emphasized that the SHG effect is extremely rare for Mn­(II) compounds, and complex 2 is likely just a third example endowed with such remarkable feature. Overall, several organic–inorganic metal halides endowed with the SHG effect have been reported previously. , …”

Unveiling the Interaction Mechanisms of Electron and X‐ray Radiation with Halide Perovskite Semiconductors using Scanning Nanoprobe Diffraction

“…[ 1 ] Heterogeneity, particularly on the nano‐ and microscale, is key to understanding some of the critical questions on performance and stability. [ 1–3 ] Scanning nanoprobe characterization techniques, such as scanning electron diffraction (SED) or nanoprobe X‐ray diffraction (nXRD), are particularly advantageous as they can access both the relevant nano‐ and microscales. [ 4,5 ]…”

“…[1] Heterogeneity, particularly on the nanoand microscale, is key to understanding some of the critical questions on performance and stability. [1][2][3] Scanning nanoprobe characterization techniques, such as scanning electron diffraction (SED) or nanoprobe X-ray diffraction (nXRD), are particularly advantageous as they can access both the relevant nano-and microscales. [4,5] Both techniques use focused radiation, which interacts with the material and can impact its structure and chemistry, especially for materials with complex stoichiometries such as hybrid halide perovskites that mix organic and inorganic ions.…”