Preparation and characterization of narrow bandgap ferroelectric (K,Ba)(Ni,Nb)O_3−δ films for mesoporous all-oxide solar cells

Abstract

Ferroelectric (K,Ba)(Ni,Nb) d -O 3 films have triggered intense studies for applications in photovoltaic device due to their efficient ferroelectric polarization-driven carrier separation and above-bandgap generated photovoltages. However, they are suffered from a challenge of preparation limiting novel device architectures. Meanwhile, the bandgap for most of ferroelectric materials reported so far is still too large to be considered for desirable spectral absorption. Here, we propose a unique strategy to successfully synthesize the (K,Ba)(Ni,Nb) d -O 3 films with the lower bandgap of about 1.45 eV. A new cell structure of utilizing (K,Ba)(Ni,Nb) d -O 3 as a active layer is explored to interface with electrontransporting TiO 2 . Such mesoporous-ferroelectric combination solar cell is beneficial for facilitating the extraction of photocarriers. Under standard AM 1.5G irradiation, the optimized (K,Ba)(Ni, Nb) d -O 3 film solar cell exhibits a higher open-circuit voltage of 1.27 V than those of previous reports on ferroelectrics. Furthermore, a fill factor of 64% and a power conversion efficiency of 0.2% are achieved via the polarization switching modulation. The present results provide a novel synthetic approach toward developing high performance solar cells based on lead-free ferroelectric films.

Highly Sensitive and Tunable Self-Powered UV Photodetectors Driven Jointly by p-n Junction and Ferroelectric Polarization

“…As shown in Figure a, the NiO/PLZT heterojunctions were constructed on FTO-coated glass substrates. NiO was selected as the p-type semiconductor layer for its low cost, good stability, and high mobility (25 cm 2 V –1 s –1 ) . According to our previous study of UPS on PLZT, it is an n-type semiconductor, , which leads to the formation of a p-n junction at the NiO/PLZT interface.…”

“…NiO was selected as the p-type semiconductor layer for its low cost, good stability, and high mobility (25 cm 2 V −1 s −1 ). 35 According to our previous study of UPS on PLZT, it is an ntype semiconductor, 30,36 which leads to the formation of a p-n junction at the NiO/PLZT interface. Combining the p-n junction with E dp that arises from the PLZT can promote efficient separation of photo-generated carriers.…”

Connecting Experimental Synthetic Variables with the Microstructure and Electronic Properties of Doped Ferroelectric Oxides Using High-Throughput Frameworks

“…This approach only considers the polarization due to atom displacements with respect to their centrosymmetric positions, but it is accurate enough to predict the KNbO 3 bulk P , 35 µC cm −2 , compared to experimental values, 37-41 µC cm −2 [78][79][80]. [11,81]. This solid solution has been widely studied because it fulfils the main requirements to be used in photovoltaic devices, exhibiting ferroelectricity and a customizable band gap in the visible region [11,23] However, the properties of this solid solution are highly dependent on dopant concentration [23,27,82], synthesis method [83][84][85][86] and temperature [25,87,88].…”

Unleashing the Potential of Strain-Engineered Ferroelectric Oxynitrides for Optimal Photovoltaic Performance

“…Unlike their conventional counterparts, the exceptional photovoltaic effect exhibited by ferroelectrics can surpass the Shockley–Queisser limitation and deliver an above-band gap open-circuit voltage. , The observed above-band gap voltage of approximately 16 V in BiFeO 3 films by Yang et al, along with subsequent observations of switchable photovoltaic response , and diode effects in ferroelectrics, have sparked a heightened interest in these materials for optoelectronic devices. Several ferroelectric materials, including BaTiO 3 , , BiFeO 3 , , Li­(K)­NbO 3 , , NaNbO 3 , and Pb­(ZrTi)­O 3 , , have been extensively studied for their photovoltaic effects. The maximum PCE achieved in ferroelectric photovoltaic devices to date is 8.1% in Bi 2 FeCrO 6 thin films .…”