Enhanced performance of BiFeO3@nitrogen doped TiO2 core-shell structured nanocomposites: Synergistic effect towards solar cell amplification

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A core-shell nano-heterostructured perovskite BiFO3@nitrogen doped mesoporous TiO2 (BFO/n-TiO2) hydrothermally assembled via using citric acid and polyethlene glycol (PEG) was characterized through XRD, TEM, FTIR, UV–Vis diffuse reflectance, IPCE, N2 adsorption and impedance spectroscopy. It has been demonstrated that the photovoltaic yield of the 90%N-TiO2-10%BFO electrode achieves a power conversion efficiency (PCE) of 4.5%, which is 1.85, 2.5, 3 and 1202 times higher than those of 10%N-TiO2-90%BFO, 50%N-TiO2-50%BFO, n-TiO2 and pristine BFO, respectively. It is acknowledged that the former electrode exhibits a significant visible light harvesting capability, lowest band gap (Eg = 2.0 eV) as well as the highest IPCE% (36% at 460 nm) values. The EIS and capacitance results illustrated that 90%N-TiO2-10%BFO owns excessive charge carriers (e− − h+); compared to rest of nanocomposites, with a great sparation, to assist boosting the PCE value. This was highly aided by the surface defects seen on the core represented by BFO, which worked as a rational carrier trapper between the N719 dye and the n-TiO2 shell structure. The surface texturing properties of the nanocomposite forming the 90%N-TiO2-10%BFO electrode including SBET (Asahi et al., 2001) and pore volume (0.48 cm3 g−1) have shared significantly in improving the conversion efficiency of such p-n heterojunction based solar cells; which never achieved as such in all BFO-based solar cell devices, with acceptable tunability.