Vapor-Phase Formation of a Hole-Transporting Thiophene Polymer Layer for Evaporated Perovskite Solar Cells.

Homogeneous layer formation on textured silicon substrates is essential for the fabrication of highly efficient monolithic perovskite silicon tandem solar cells. From all well-known techniques for the fabrication of perovskite solar cells (PSCs), the evaporation method offers the highest degree of freedom for layer-by-layer deposition independent of the substrate's roughness or texturing. Hole-transporting polymers with high hole mobility and structural stability have been used as effective hole-transporting materials (HTMs) of PSCs.

Anti-Oxidizing Radical Polymer-Incorporated Perovskite Layers and their Photovoltaic Characteristics in Solar Cells.

A small amount of a radical-bearing redox-active polymer, poly(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl methacrylate) (PTMA), incorporated into the photovoltaic organo-lead halide perovskite layer significantly enhanced durability of both the perovskite layer and its solar cell and even exposure to ambient air or oxygen. PTMA acted as an eliminating agent of the superoxide anion radical formed upon light irradiation on the layer, which can react with the perovskite compound and decompose it to lead halide. A cell fabricated with a PTMA-incorporated perovskite layer and a hole-transporting polytriarylamine layer gave a photovoltaic conversion efficiency of 18.