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Hybrid Perovskite Materials and Their Applications
Published in Song Sun, Wei Tan, Su-Huai Wei, Emergent Micro- and Nanomaterials for Optical, Infrared, and Terahertz Applications, 2023
The two-step process, also known as the sequential deposition method, involves (i) the deposition of Pb halide or Pb-based adduct onto a substrate, (ii) exposure to a liquid, vapor, or solid of organic salt, and (iii) formation of perovskite film by heat-assisted diffusion reaction. This process allows for better control of the reaction between Pb halide and organic salt, which induces the crystallization of perovskite materials. The detailed deposition process, such as the speed of spin coating, the time socking in the methylammonium iodide (MAI) solution, the substrate heating, could have a strong influence on the grain size and converge of perovskite film that are critical to its performance. Mixed halide materials, such as FA- and MA-based perovskite materials, could also be synthesized using the two-step process, yielding an efficiency as high as 14.9% with superior light-harvesting and charge-collection performance. It is also found that the first intramolecular exchange process, in which the PbI2·DMSO film was first deposited, flowed by the deposition of (CH5IN2)FAI and post-annealing could enable a high PCE of 20.1%.
New Approaches: Testing the Limits in Organic Solar Cells
Published in Theodore Goodson, Solar Fuels, 2017
While we have given many important details of the preparation and properties of all organic solar materials, it is now important in this chapter to relate some of the basic structural properties of perovskites. As mentioned earlier, the structure of these interesting materials follow the repeating formula of ABX3, where X is either oxygen or a halogen, and A and B are cations that have 12 and 6 coordination with the X halogen. The structural motif is characterized by a tolerance factor, which is a measure of the stability of the final structure in the presence of distortions.46 In practice, the formation of perovskites used for solar cells have included lead (Pb) and tin (Sn) as the “A” cation and a methylammonium ligand (CH3NH3) as the “B” cation. The halide or “X” is typically iodine (I) or bromine (Br).47 For the typical case of iodine-containing perovskites, one initially starts with a methylamine (CH3NH2) in EtOH and adds to this an equimolar amount of hydroidic acid at 0°C for several hours in order to make the methylammonium iodide.48 The crystallization of CH3NH3I can be accomplished through evaporation procedures by adding a small amount of heat over time.49 In order to obtain the precursor, CH3NH3I is mixed with lead iodide (PbI2) dissolved in solvent and stirred for several hours with heat. The precursor CH3NH3PbI3 has been demonstrated to provide a good yield when the preparation is carried out in this manner.48Similar procedures can be carried out for the formation of the Br precursor as well (Figure 6.7).50 It should be noted that this relatively straight forward approach to synthesis of the pervoskites makes for an excellent educational excercise.
Processing of Nanocomposite Solar Cells in Optical Applications
Published in Kaushik Pal, Hybrid Nanocomposites, 2019
Recently, Jen et al. achieved a PCE as high as 17.74% by using a combustion method to prepare a Cu-doped NiOx hole contact for PSCs [89]. High-quality perovskite films were made by Burschka et al. (2013), who identified the value of perovskite films for highly efficient PSCs. They developed spin coating of methylammonium iodide with a two-step deposition technique and subsequent submerging into a lead halide solution.
Homogeneous and highly controlled deposition of low viscosity inks and application on fully printable perovskite solar cells
Published in Science and Technology of Advanced Materials, 2018
Simone M. P. Meroni, Youmna Mouhamad, Francesca De Rossi, Adam Pockett, Jennifer Baker, Renán Escalante, Justin Searle, Matthew J. Carnie, Eifion Jewell, Gerko Oskam, Trystan M. Watson
The effectiveness of the RbM technique was compared to a conventional manual drop deposition method in terms of performance and stability on 1 devices. A 2-step deposition method, where lead iodide () is dropped into the film and converted by immersion of the whole film in a methylammonium iodide (MAI) solution to form methylamine lead iodide (, MAPI) perovskite, was adopted following the method of Han et al. [16]. The use of , bright yellow, allows a visual monitoring of its infiltration through the mesoporous layers. The homogeneity of the deposition was determined by X-ray diffraction (XRD) sampling and Raman mapping. This mechanised infiltration method has the potential to automate the final stages of device fabrication. This means that from the introduction of the substrate through to the completion of an encapsulated device, the sequential layering by screen printing, infiltration using the RbM, and a final dip process are all mechanised and uniform. This has significant potential for unlocking high-volume continuous manufacture.