Thiazolidinone-Based Electron-Collecting Monolayers for n-i-p Perovskite Solar Cells.

The development of efficient electron-collecting monolayer materials is desired to lower manufacturing costs and improve the performance of regular (negative-intrinsic-positive, n-i-p) type perovskite solar cells (PSCs). Here, we designed and synthesized four electron-collecting monolayer materials based on thiazolidinone skeletons, with different lowest-unoccupied molecular orbital (LUMO) levels (rhodanine or thiazolidinedione) and different anchoring groups to the transparent electrode (phosphonic acid or carboxylic acid). These molecules, when adsorbed on indium tin oxide (ITO) substrates, lower the work function of ITO, decreasing the energy barrier for electron extraction at the ITO/perovskite interface and improving the device performance.

Molecular Design of Hole-Collecting Materials for Co-Deposition Processed Perovskite Solar Cells: A Tripodal Triazatruxene Derivative with Carboxylic Acid Groups.

High-performance and cost-effective hole-collecting materials (HCMs) are indispensable for commercially viable perovskite solar cells (PSCs). Here, we report an anchorable HCM composed of a triazatruxene core connected with three alkyl carboxylic acid groups (). In contrast to the phosphonic acid-containing tripodal analog (), molecules can form a hydrophilic monolayer on a transparent conducting oxide surface, which is beneficial for subsequent perovskite film deposition in the traditional layer-by-layer fabrication process.

Single-isomer bis(pyrrolidino)fullerenes as electron-transporting materials for tin halide perovskite solar cells.

Although fullerene bisadducts are promising electron-transporting materials for tin halide perovskite solar cells, they are generally synthesized as a mixture of isomeric products that require a complicated separation process. Here, we introduce a phenylene-bridged bis(pyrrolidino)fullerene, Bis-PC, which forms only a single isomer due to geometrical restriction. When used in a tin perovskite solar cell with a PEAFASnI (PEA: phenylethylammonium and FA: formamidinium) light absorption layer, the resulting open-circuit voltage ( ) was 0.

Steering perovskite precursor solutions for multijunction photovoltaics.

Multijunction photovoltaics (PVs) are gaining prominence owing to their superior capability of achieving power conversion efficiencies (PCEs) beyond the radiative limit of single-junction cells, where improving narrow bandgap tin-lead perovskites is critical for thin-film devices. With a focus on understanding the chemistry of tin-lead perovskite precursor solutions, we herein find that Sn(II) species dominate interactions with precursors and additives and uncover the exclusive role of carboxylic acid in regulating solution colloidal properties and film crystallisation, and ammonium in improving film optoelectronic properties. Materials that combine these two function groups, amino acid salts, considerably improve the semiconducting quality and homogeneity of perovskite films, surpassing the effect of the individual functional groups when introduced as part of separate molecules.