Function Follows Form: Correlation between the Growth and Local Emission of Perovskite Structures and the Performance of Solar Cells

Abstract

Understanding the relation between the growth and local emission of hybrid perovskite structures, and the performance of the devices based on them demands attention. In this study, we have investigated the local structural and emission features of CH 3 NH 3 PbI 3 , CH 3 NH 3 PbBr 3 and CH(NH 2 ) 2 PbBr 3 perovskite films deposited under different yet optimized conditions using X-ray scattering and cathodoluminescence spectroscopy, respectively. X-ray scattering shows that CH 3 NH 3 PbI 3 film involving spin coating of CH 3 NH 3 I instead of dipping is composed of perovskite structures exhibiting a preferred orientation with [202] direction perpendicular to the surface plane. The device based on the CH 3 NH 3 PbI 3 film composed of oriented crystals yield a higher photovoltage. In case of CH 3 NH 3 PbBr 3 , while the crystallinity decreases when the HBr solution is used in a single-step method, the photovoltage enhancement from 1.1 to 1.46 V seems largely stemming from the morphological improvements, i.e. a better connection between the crystallites due to a higher nucleation 2 density. Furthermore, a high photovoltage of 1.47 V obtained from CH(NH 2 ) 2 PbBr 3 devices could be attributed to the formation of perovskite films displaying uniform cathodoluminescence emission. The comparative analysis of the local structural, morphological, and emission characteristics of the different perovskite films support the higher photovoltage yielded by the relatively better performing devices.

Formamidinium‐Based Lead Halide Perovskites: Structure, Properties, and Fabrication Methodologies

“…FAPbBr 3 films have a wider bandgap in comparison to FAPbI 3 , which makes them less suitable for photovoltaic applications due to the reduced overlap with the solar spectrum. However, FAPbBr 3 ‐based devices commonly exhibit a very high open‐circuit voltage of ≈1.5 V . In addition, FAPbBr 3 ‐based devices also exhibited good stability .…”

Reduced Graphene Oxide as a Stabilizing Agent in Perovskite Solar Cells

“…In this regard, improving the long‐term stability of perovskite solar cells requires focusing on adjacent layers . However, modification of the perovskite absorption layer is one of the most challenging tasks in tuning the performance of thin‐film PSCs . This is particularly owing to its sensitivity to hydrophobic additives that can affect the crystallinity of the material, morphology of the films, and consequently performance of the devices .…”

CsxFA1–xPb(I1–yBry)3 Perovskite Compositions: the Appearance of Wrinkled Morphology and its Impact on Solar Cell Performance

“…26 Also, the film morphology itself plays a significant role in the corresponding performance metrics of perovskite solar cells. 33,[35][36][37][38] Thus, we herein investigate key parameters that influence the formation of wrinkled perovskite films and compare their optoelectronic properties to perovskite layers of the same composition exhibiting a flat morphology. By carefully tuning the film processing parameters we can generate deliberately flat and wrinkled films (Figure 1b-g).…”