Synthesis of perovskite [KNbO₃]_0,9[BaNi_0,5Nb_0,5O_3-δ]_0,1 by solution combustion

The development of visible-light-absorbing ferroelectric perovskite materials, particularly KBNNO – [KNbO₃ ]_0.9[BaNi_0.5Nb_0.5O_3-δ ]_0.1 (band-gap E_g = 1.39 eV), has provided encouragement for the use of such materials in photoactive layers. When applied in photovoltaic devices, these materials might generate above-bandgap photovoltages and a more efficient separation of charge carriers. The synthesis of this oxide as a powder with high surface area might be a strategy to further incorporation in solar cells composed of low-temperature processing materials. This work reports for the first time the application of the solution combustion as an alternative route for the synthesis of KBNNO. Characterization by XRD, SEM, EDS, TG/DSC and diffuse reflectance UV-vis spectroscopy confirmed the success of the synthesis. The optical properties showed the visible-light absorption contribution and band-gap close to the ideal magnitude for solar applications. (author)