Researchers at Martin Luther University Halle-Wittenberg (MLU) have discovered a new method to increase the efficiency of solar cells by a factor of 1,000. The team of scientists achieved this breakthrough by creating crystalline layers of barium titanate, strontium titanate, and calcium titanate, which were alternately placed on top of one another in a lattice structure. Their findings, which could revolutionize the solar energy industry.
Solar cells currently in use are mostly silicon-based, but their efficiency is limited. This has led researchers to explore new materials, such as ferroelectrics like barium titanate, which is a mixed oxide made of barium and titanium. Ferroelectric materials have spatially separated positive and negative charges, which leads to an asymmetric structure that generates electricity from light. Unlike silicon, ferroelectric crystals do not require a pn junction to create the photovoltaic effect, making it easier to produce solar panels.
However, pure barium titanate does not absorb much sunlight, resulting in a relatively low photocurrent. The new research has shown that combining extremely thin layers of different materials significantly increases the solar energy yield.
This new development has far-reaching implications for the solar industry. Solar panels made with this new material would be significantly more efficient, and the cost of producing them would be lower than silicon-based solar cells. Furthermore, they would require less space to generate the same amount of electricity, making them ideal for use in urban areas where space is limited.
Abstract :
Ever since the first observation of a photovoltaic effect in ferroelectric BaTiO3, studies have been devoted to analyze this effect, but only a few attempted to engineer an enhancement. In conjunction, the steep progress in thin-film fabrication has opened up a plethora of previously unexplored avenues to tune and enhance material properties via growth in the form of superlattices. In this work, we present a strategy wherein sandwiching a ferroelectric BaTiO3 in between paraelectric SrTiO3 and CaTiO3 in a superlattice form results in a strong and tunable enhancement in photocurrent. Comparison with BaTiO3 of similar thickness shows the photocurrent in the superlattice is 10^3 times higher, despite a nearly two-thirds reduction in the volume of BaTiO3. The enhancement can be tuned by the periodicity of the superlattice, and persists under 1.5 AM irradiation. Systematic investigations highlight the critical role of large dielectric permittivity and lowered bandgap.
Solar cells currently in use are mostly silicon-based, but their efficiency is limited. This has led researchers to explore new materials, such as ferroelectrics like barium titanate, which is a mixed oxide made of barium and titanium. Ferroelectric materials have spatially separated positive and negative charges, which leads to an asymmetric structure that generates electricity from light. Unlike silicon, ferroelectric crystals do not require a pn junction to create the photovoltaic effect, making it easier to produce solar panels.
However, pure barium titanate does not absorb much sunlight, resulting in a relatively low photocurrent. The new research has shown that combining extremely thin layers of different materials significantly increases the solar energy yield.
This new development has far-reaching implications for the solar industry. Solar panels made with this new material would be significantly more efficient, and the cost of producing them would be lower than silicon-based solar cells. Furthermore, they would require less space to generate the same amount of electricity, making them ideal for use in urban areas where space is limited.
Abstract :
Ever since the first observation of a photovoltaic effect in ferroelectric BaTiO3, studies have been devoted to analyze this effect, but only a few attempted to engineer an enhancement. In conjunction, the steep progress in thin-film fabrication has opened up a plethora of previously unexplored avenues to tune and enhance material properties via growth in the form of superlattices. In this work, we present a strategy wherein sandwiching a ferroelectric BaTiO3 in between paraelectric SrTiO3 and CaTiO3 in a superlattice form results in a strong and tunable enhancement in photocurrent. Comparison with BaTiO3 of similar thickness shows the photocurrent in the superlattice is 10^3 times higher, despite a nearly two-thirds reduction in the volume of BaTiO3. The enhancement can be tuned by the periodicity of the superlattice, and persists under 1.5 AM irradiation. Systematic investigations highlight the critical role of large dielectric permittivity and lowered bandgap.
