In this work, nickel silicide was applied to tandem solar cells as an interlayer. By the process of thermal evaporation, a layer of NiOx, hole transport layer (HTL) was deposited on n+ poly-Si layer directly. Nickel silicide was simultaneously formed by nickel diffusion from NiOx to n+ poly-Si layer during the deposition and annealing process. The I–V characteristics of NiOx/n+ poly-Si contact with nickel silicide showed ohmic contact and low contact resistivity. This structure is expected to be more advantageous for electrical connection between perovskite top cell and TOPCon bottom cell compared to the NiOx/TCO/n+ poly-Si structure showing Schottky contact. Furthermore, nickel silicide and Ni-deficient NiOx thin film formed by diffusion of nickel can improve the fill factor of the two sub cells. These results imply the potential of a NiOx/nickel silicide/n+ poly-Si structure as a perovskite/silicon tandem solar cell interlayer.
Perovskite-based tandem solar cells
are promising candidates for
industrial applications. This study demonstrated perovskite/silicon
tandem devices based on a conventional Si homojunction device configuration
employing a tunnel oxide passivating contact to improve the voltage.
Moreover, we fabricated it without the deposition of a recombination
layer on a large area while showing the possibility of applying the
industry market. This solar cell exhibited a power conversion efficiency
of 17.3% and a high voltage of 1783 mV on a 25 cm2 active
area.
Monolithic perovskite–silicon tandem solar cells with MoOx hole selective contact silicon bottom solar cells show a power conversion efficiency of 8%. A thin 15 nm-thick MoOx contact to n-type Si was used instead of a standard p+ emitter to collect holes and the SiOx/n+ poly-Si structure was deposited on the other side of the device for direct tunneling of electrons and this silicon bottom cell structure shows ~15% of power conversion efficiency. With this bottom carrier selective silicon cell, tin oxide, and subsequent perovskite structure were deposited to fabricate monolithic tandem solar cells. Monolithic tandem structure without ITO interlayer was also compared to confirm the role of MoOx in tandem cells and this tandem structure shows the power conversion efficiency of 3.3%. This research has confirmed that the MoOx layer simultaneously acts as a passivation layer and a hole collecting layer in this tandem structure.
Tandem solar cells, based on perovskite and crystalline silicon absorbers, are promising candidates for commercial applications. Tin oxide (SnO2), applied via the spin-coating method, has been among the most used electron transfer layers in normal (n-i-p) perovskite/silicon tandem cells. SnO2 synthesized by chemical bath deposition (CBD) has not yet been applied in tandem devices. This method shows improved efficiency in perovskite single cells and allows for deposition over a larger area. Our study is the first to apply low-temperature processed SnO2 via CBD to a homojunction silicon solar cell without additional deposition of a recombination layer. By controlling the reaction time, a tandem efficiency of 16.9% was achieved. This study shows that tandem implementation is possible through the CBD method, and demonstrates the potential of this method in commercial application to textured silicon surfaces with large areas.
Tunnel oxide passivated contact (TOPCon) solar cells are key emerging devices in the commercial silicon-solar-cell sector. It is essential to have a suitable bottom cell in perovskite/silicon tandem solar cells for commercial use, given that good candidates boost efficiency through increased voltage. This is due to low recombination loss through the use of polysilicon and tunneling oxides. Here, a thin amorphous silicon layer is proposed to reduce parasitic absorption in the near-infrared region (NIR) in TOPCon solar cells, when used as the bottom cell of a tandem solar-cell system. Lifetime measurements and optical microscopy (OM) revealed that modifying both the timing and temperature of the annealing step to crystalize amorphous silicon to polysilicon can improve solar cell performance. For tandem cell applications, absorption in the NIR was compared using a semitransparent perovskite cell as a filter. Taken together, we confirmed the positive results of thin poly-Si, and expect that this will improve the application of perovskite/silicon tandem solar cells.
Current density plays a substantial role in monolithic tandem solar cells; however, it is difficult to control because subcells and auxiliary layers are stacked and serially connected vertically to obtain higher voltages. The vertically stacked structure intrinsically triggers inevitable parasitic absorption. In current typical perovskite/silicon two-terminal (2-T) tandem solar cells, 5−10 layers are placed on the light path, even though they are not current generating layers. These layers usually include transparent window layers, buffer layers, carrier extraction layers, and recombination layers. Therefore, the development of top contact-free architectures to reduce parasitic absorption in 2-T tandem solar cells is required for achieving high efficiency. In this study, a top contact-free perovskite/silicon 2-T tandem solar cell with quasi-interdigitated intermediate electrodes (Q-IDIEs) is reported for the first time. Several layers placed above the perovskite layer in conventional devices are relocated to the backside of the perovskite. The Q-IDIE, composed of a patterned Ni/NiO X shell above the full-deposited TiO 2 , was fabricated by the following processes: photolithography, lift-off, and oxidation. The device results in 4.23% efficiency with an open-circuit voltage of 1.54 V. This tandem architecture is expected to be a breakthrough for overcoming the theoretical efficiency limit of single-junction solar cells with further optimization.
We performed molecular dynamics simulations of the systems consisting of C 60 molecules and dipalmitoylphosphatidylcholine (DPPC) monolayer membranes to study the penetration of C 60 into lung surfactant (LS) membranes. The potential of mean force of the C 60 penetration through the LS membrane was calculated as a function of the distance of a C 60 molecule from the DPPC monolayer membrane. The free energy minimum of around 43 kcal/mol is located in the DPPC tail region, indicating that the C 60 molecules can accumulate in the LS membrane region. The energy decomposition shows the main driving force of the C 60 accumulation in the lipid tail region is the van der Waals interaction with the hydrocarbon tails of DPPC lipids. Finally, we observed that the water evaporation rate can be significantly enhanced by the accumulation of C 60 molecules in the membrane tail region. K E Y W O R D S dipalmitoylphosphatidylcholine (DPPC), fullerene (C 60 ), lung surfactant membrane, molecular dynamics (MD) simulation, potential of mean force (PMF), umbrella sampling
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