The hybrid halide perovskite methyl ammonium lead iodide thiocyanate – (CH3NH3)Pb(SCN)2I2 – is synthesized both as a powder and as a thin film. The crystal structure and key optical properties (band gap) are determined by diffuse reflectance spectra and X ‐ray diffraction (Rietveld refinement) measurements and compared to density functional theory (DFT) state‐of‐the‐art calculations. It is found that the refined orthorhombic crystal structure presents 2D‐layer confinement, and that the optical band gap presented in this work does confirm some previous reports and rebuts other results, too.
En el presente trabajo se sintetizaron, caracterizaron y estudiaron una serie de capas delgadas de molibdeno metálico, optimizando sus propiedades para ser usadas como contactos eléctricos en celdas sola- res tipo tándem. Se estableció el dispositivo experimental adecuado para la preparación de las películas delgadas ya mencionadas, y a través de medidas de resistencia eléctrica, difracción de rayos X, microscopía de fuerza atómica y perfilometría en 2D, se encontraron los parámetros de síntesis que aseguran para los materiales propiedades óptimas en términos de cristalinidad, espesor de película y resistencia de hoja RS. Se logró optimizar las películas presentando la resistencia eléctrica, espesor y cristalinidad apropiadas para ser usadas como contacto eléctrico inferior en celdas solares tipo tándem.
Herein, mixed CH3NH3PbI3/(CH3NH3)2PbI2(SCN)2 (MAPI/MAPSI) thin films are synthesized. Arising from X‐ray diffraction measurements, the composite material is found to be consisting of two crystalline domains, one for each MAPI and MAPSI constitutent materials. Optical analysis from diffuse reflectance spectroscopy shows optical onsets for both the MAPI and MAPSI domains, making the fabricated material an interesting one for multi‐bandgap absorber composite for solar cell devices. Scanning electron microscopy studies yield a noticeable morphology enhancement for the MAPI/MAPSI films when treated with a toluene dripping technique, and then show films with uniform, compact grains in contrast to an initial porous, dendritic growth morphology for the untreated films. A question about the actual geometry for the thiocyanate anions in MAPSI is answered as being of axial configuration around the Pb cation, enlightened by the results of state‐of‐the‐art density functional theory computational modelling within the framework of the Quantum Espresso software package suite, also in‐depth studying of the MAPSI structure through bond indicators such as crystal orbital Hamilton population, non‐covalent interactions analysis, and electron localization function.
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