Perovskite solar cells containing a mixture of A-site cations show increased activation energies for iodide diffusion.

Organic–inorganic hybrid perovskite solar cells (PSC) are promising third‐generation solar cells. They exhibit good power conversion efficiencies and in principle they can be fabricated with lower energy consumption than many more established technologies. To improve the efficiency and long‐term stability of PSC, organic molecules are frequently used as “interlayers.” Interlayers are thin layers or monolayers of organic molecules that modify a specific interface in the solar cell. Here, the latest progress in the use of interlayers to optimize the performance of PSC is reviewed. Where appropriate interesting examples from the field of organic photovoltaics (OPV) are also presented as there are many similarities in the types of interlayers that are used in PSC and OPV. The review is organized into three parts. The first part focuses on why organic molecule interlayers improve the performance of the solar cells. The second section discusses commonly used molecular interlayers. In the last part, different approaches to make thin and uniform interlayers are discussed.

Hybrid organic-inorganic perovskites have been established as good candidate materials for emerging photovoltaics, with device efficiencies of over 22 % being reported. There are currently only two organic cations, methylammonium and formamidinium, which produce 3D perovskites with band gaps suitable for photovoltaic devices. Numerous computational studies have identified azetidinium as a potential third cation for synthesizing organic-inorganic perovskites, but to date no experimental reports of azetidinium containing perovskites have been published. Here we prepare azetidinium lead iodide for the first time and show that it is a stable, bright orange material that can be successfully used as the absorber layer in solar cells.We also show that it is possible to make mixed cation devices by adding the azetidinium cation to methylammonium lead iodide. Mixed azetidinium-methylammonium cells show improved performance and reduced hysteresis compared to methylammonium lead iodide cells.

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We report the surface nucleated growth of self-assembled dipeptide films. The seeding-layer was a thin dipeptide film with a globular structure. Placing the seeding-layer in contact with dipeptide led to growth of fibres overnight. Active enzymes were incorporated into the gel by adding them to the growth solution.

Perovskite nanocrystals prepared at room temperature using a simple flow reactor.

We present a method for the polymerization of low molecular weight hydrogelators to form polymers with unique structures. Carbazole-protected amino acids are shown to form hydrogels by self-assembly into fibrous structures. We show that is possible to directly electropolymerize the hydrogels. This results in the formation of microporous electrochromic polymers with distinctive structure. Polymers formed from the same gelator without the pregelation step show more compact structures. This method opens the possibility of creating polymers templated from pre-assembled gels that have the potential to be used in a wide range of applications.

Here we describe preliminary studies into the synthesis structural characterisation and thermal properties of a family of calcium xanthate precursors for application in the deposition of CaS thin films. The straightforward, low‐temperature syntheses are detailed along with characterisation of the resulting compounds by 1H and 13C NMR and elemental analysis. Solid state molecular structures of all compounds, obtained from single‐crystal X‐ray diffraction, are presented and discussed in detail. The decomposition behaviour of the precursors has been probed through TGA, TGA‐MS and thermal annealing experiments, indicating that the compounds decompose cleanly into CaS.