Search

Imaging mechanisms in contact Kelvin probe force microscopy (cKPFM) are explored via information theory-based methods. Gaussian processes are used to achieve super-resolution in the cKPFM signal, effectively extrapolating across the spatial and parameter space. Tensor factorization is applied to reduce the multidimensional signal to the tensor convolution of the scalar functions that show a clear trending behavior with the imaging parameters. These methods establish a workflow for the analysis of the multidimensional datasets that can then be related to the relevant physical mechanisms. We also provide an interactive Google Colab notebook that goes through all the analyses discussed in the paper. [ABSTRACT FROM AUTHOR]

Hybrid organic–inorganic perovskites are one of the promising candidates for the next‐generation semiconductors due to their superlative optoelectronic properties. However, one of the limiting factors for potential applications is their chemical and structural instability in different environments. Herein, the stability of (FAPbI3)0.85(MAPbBr3)0.15 perovskite solar cell is explored in different atmospheres using impedance spectroscopy. An equivalent circuit model and distribution of relaxation times (DRTs) are used to effectively analyze impedance spectra. DRT is further analyzed via machine learning workflow based on the non‐negative matrix factorization of reconstructed relaxation time spectra. This exploration provides the interplay of charge transport dynamics and recombination processes under environment stimuli and illumination. The results reveal that in the dark, oxygen atmosphere induces an increased hole concentration with less ionic character while ionic motion is dominant under ambient air. Under 1 Sun illumination, the environment‐dependent impedance responses show a more striking effect compared with dark conditions. In this case, the increased transport resistance observed under oxygen atmosphere in equivalent circuit analysis arises due to interruption of photogenerated hole carriers. The results not only shed light on elucidating transport mechanisms of perovskite solar cells in different environments but also offer an effective interpretation of impedance responses. [ABSTRACT FROM AUTHOR]

Organic electron‐transporting materials (ETMs) with low‐temperature solution processability and high electron‐transfer/transport characteristics have received significant attention for their use in high‐performance perovskite solar cells (PSCs). In contrast to widely investigated fullerene‐based organic ETMs for PSCs, only a few types of non‐fullerene‐based ETMs have been developed. In this Concept article, a representative design concept for non‐fullerene ETMs is described for use in normal (n‐i‐p) and inverted (p‐i‐n) type PSCs. On the basis of a discussion on ETM requirements for PSCs, recently developed non‐fullerene polymeric and small‐molecule‐based ETMs for PSCs are highlighted, alongside various other approaches for enhancing PSC device performance, such as using additional dopants and introducing amine terminal groups in the ETMs and ETM‐based interlayers. This Concept provides a basic design concept for non‐fullerene‐based ETMs in PSCs. A place in the sun: This Concept article describes the representative design concept of non‐fullerene organic electron‐transporting materials (ETMs) for normal‐ and inverted‐structured perovskite solar cells (PSCs). A discussion of the requirements of ETMs for PSCs is also discussed (HTM=hole‐transporting material; TCO=transparent conducting oxide). [ABSTRACT FROM AUTHOR]

The Front Cover shows high performance perovskite solar cells (PSCs) based on non‐fullerene organic electron transporting materials (ETMs). Organic ETMs are very attractive for high performance PSCs due to their efficient electron transporting characteristics and low‐temperature solution processability. In their Concept, S.‐K. Jung, D. S. Lee et al. discuss representative design concepts of non‐fullerene polymeric and small molecular‐based ETMs for normal and inverted PSCs and their ETM requirements. More information can be found in the Concept by S.‐K. Jung, D. S. Lee et al. on page 3882 in Issue 22, 2018 (DOI: 10.1002/cssc.201801908). [ABSTRACT FROM AUTHOR]

Invited for this month′s cover is the collaborative team of the groups of O‐Pil Kwon and Jong H. Kim at Ajou University and Sang Hyuk Im at Korea University. The image shows non‐fullerene organic electron transporting materials for perovskite solar cells. The Concept itself is available at 10.1002/cssc.201801908. "ETMs are very attractive for PSCs..." This and more about the story behind the research that inspired the Cover image is presented in the Cover Profile. Read the full text of the corresponding article at 10.1002/cssc.201801908. View the Front Cover here: 10.1002/cssc.201802623. [ABSTRACT FROM AUTHOR]