Polymer/Inorganic Hole Transport Layer for Low-Temperature-Processed Perovskite Solar Cells

In the search for improvements in perovskite solar cells (PSCs), several different aspects are currently being addressed, including an increase in the stability and a reduction in the hysteresis. Both are mainly achieved by improving the cell structure, employing new materials or novel cell arrangements. We introduce a hysteresis-free low-temperature planar PSC, composed of a poly(3-hexylthiophene) (P3HT)/CuSCN bilayer as a hole transport layer (HTL) and a mixed cation perovskite absorber. Proper adjustment of the precursor concentration and thickness of the HTL led to a homogeneous and dense HTL on the perovskite layer. This strategy not only eliminated the hysteresis of the photocurrent, but also permitted power conversion efficiencies exceeding 15.3%. The P3HT/CuSCN bilayer strategy markedly improved the life span and stability of the non-encapsulated PSCs under atmospheric conditions and accelerated thermal stress. The device retained more than 80% of its initial efficiency after 100 h (60% after 500 h) of continuous thermal stress under ambient conditions. The performance and durability of the PSCs employing a polymer/inorganic bilayer as the HTL are improved mainly due to restraining perovskite ions, metals, and halides migration, emphasizing the pivotal role that can be played by the interface in the perovskite-additive hole transport materials (HTM) stack

The development of water-based primers for coil coating applications.

In the search for improvements in the environmental credentials of the organic coatings industry, several different aspects are currently being addressed, including the reduction of volatile organic compounds, development of UV curable coatings and the reduction of potentially hazardous components in the coatings formulations. The aim of this work was to develop the water based primers for coil coating applications as a substitution for chromate conversion coatings. The performance and durability of three novel water based systems applied on alkali cleaned HDGS has been investigated; XPS and ToF-SIMS have been employed to analyse the failure interfaces generated by various test methods designed to assess the performance and durability of each of the systems. In depth analysis has been carried out using ULAM for sample preparation, and XPS and ToF-SIMS were employed to analyse the buried metal/ primer interface, in order to investigate the interface chemistry. A method of post processing data, obtained by surface analysis techniques, was invented to gain a clear understanding of the possible chemical interactions occurred at the metal/primer interface. Adsorption studies were also carried out to encode the interfacial chemistry. The method was used to understand the role of adhesion promoter in the primer formulation, particularly the manner in which it interacts with the substrate and the topcoat and the way it improves the performance and durability; also to determine the role of anti-corrosive additives, especially the manner in which it prevents the corrosion and therefore its contribution toward the performance and durability. The distribution of these components across the primer layer was also investigated considering the possible opportunities of such components enhancing the primer interaction at either interfaces. The finding has been used for re-adjustment of some of process parameters in coil coating systems and specifically water based primers