KBiFe₂O₅ (KBFO) is a perovskite‐like inorganic material that has great potential as an absorber material for active layers of photovoltaic devices; however, the synthesis conditions reported until now (pressure and temperature) are inappropriate for its direct deposition on the usual substrates of solar cells. Being able to synthesize these materials directly on the substrate avoids a second stage of deposition of this material, besides improving joining properties and consequently improving energy conversion efficiency. To decrease the synthesis temperature of KBFO, the sol‐gel method was used at different times and temperatures with poly(vinylpyrrolidone) (PVP) as an accelerating agent for the kinetics of formation of the phase. Thus, the formation of the KBFO phase as powder at temperatures below 550°C and atmospheric pressure with the use of PVP as a synthesis additive is reported for the first time; however, the phase was obtained with impurities and the lower the synthesis temperature the greater the presence of impurities, but the smaller the crystallite size. Two band gaps were found for the samples: one around 2.41 and 2.07 eV and the other one around 1.76 eV. Samples synthesized at higher temperatures had a paramagnetic behavior, while samples synthesized at lower temperatures had weak ferromagnetic behavior.

中文翻译：

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使用PVP作为添加剂的溶胶-凝胶法合成的KBiFe2O5的结构，光学和磁性

溴化钾₂ O ₅（KBFO）是一种钙钛矿型无机材料，具有巨大的潜力，可以用作光伏器件有源层的吸收材料。然而，迄今为止报道的合成条件（压力和温度）尚不适合直接沉积在太阳能电池的常规基板上。能够直接在基板上合成这些材料避免了该材料沉积的第二阶段，除了改善了接合性能并因此提高了能量转换效率。为了降低KBFO的合成温度，在不同时间和温度下使用溶胶-凝胶法，并以聚（乙烯基吡咯烷酮）（PVP）为促进剂来形成相动力学。从而，首次报道了在低于550°C的温度和大气压下使用PVP作为合成添加剂形成KBFO相的粉末；然而，获得的相具有杂质，并且合成温度越低，杂质的存在越多，但微晶尺寸越小。对于样品发现两个带隙：一个在2.41和2.07 eV附近，另一个在1.76 eV附近。在较高温度下合成的样品具有顺磁行为，而在较低温度下合成的样品具有弱铁磁行为。一个大约在2.41和2.07 eV之间，另一个大约在1.76 eV附近。在较高温度下合成的样品具有顺磁行为，而在较低温度下合成的样品具有弱铁磁行为。一个大约在2.41和2.07 eV之间，另一个大约在1.76 eV附近。在较高温度下合成的样品具有顺磁行为，而在较低温度下合成的样品具有弱铁磁行为。