A numerical examine by researchers at Chitkara College in India exhibits the improved efficiency of the best machine in a tandem photo voltaic cell based mostly on copper indium gallium selenide (CIGS). The design has a better open-circuit voltage, with the highest cell performing as a present limiting cell.
Researchers at Chitkara College in India designed and simulated a two-terminal, monolithically stacked tandem photo voltaic cell based mostly on a backside cell product of perovskite with an power bandgap of 1.68 eV. The highest cell relies on CIGS, with a bandgap of 1.1 eV.
“Our patented design can stop contact recombination and related reverse saturation present to extend VOC,” mentioned researcher Rahul Pandey. pv journal.
The researchers carried out a numerical simulation to foretell the efficiency and habits of the machine, use SCAPS-1D photo voltaic cell capability sFOR essentially the most halfwhich is a simulation device for thin-film photo voltaic cells developed on the College of Ghent in Belgium.
They designed the underside cell with an indium zinc oxide (IZO) clear conductive oxide movie, a tin(IV) oxide (SnO2) buffer layer, a perovskite layer, and a layer on methyl-substituted carbazole (Me-4PACz) as a hole-transport layer. For the highest cell, they advised utilizing an indium tin oxide (ITO) substrate, a cadmium sulfide (Cds) layer, and a CIGS absorber.
“Within the prime cell, the perovskite layer acts as an absorber to soak up high-energy photons. Equally, the underside cell makes use of the CIGS layer to soak up low-energy photons,” mentioned the scientists, which signifies that the 2 cells are linked by way of an intermediate layer of ITO to supply present matching for the tandem configuration.
They examined completely different CIGS absorber layer thicknesses from 0.5 micrometers (μm) to five μm and located that there was a rise in present density resulting from larger photon absorption, in a 2.3 μm thick absorber layers. In addition they decided that there’s saturation of the present density for thicknesses larger than 2.3 μm.
With an optimized absorber thickness of two.3 μm, the decrease cell exhibits within the simulation it could possibly obtain an influence conversion effectivity of 16.26%, an open-circuit voltage of 0.64 V, a short- circuit present of 35.98 mA/cm2, and a fill. reason behind 70.51%.
“The voltage drop of the tandem photo voltaic cell is the sum of the voltage drop of the identical subcell individually, the scientists mentioned, including that the highest cell provides much less present than the underside one cell in standalone configuration and acts as a container that limits the present cell.
The tandem machine prime/underneath cell thickness of 347 nm/2.0 μm exhibits an effectivity of 29.72%, an open-circuit voltage of 1.92 V, a short-circuit present of 20.04 mA/cm2, and a fill issue of 77%.
The scientists launched the cell know-how in “Perovskite-CIGS Monolithic Tandem Photo voltaic Cells with 29.7% Effectivity: A Numerical Research,” which was just lately printed in Vitality Fuels.
“The primary limitation of the adopted filtered spectrum methodology is that it ignores interface reflection losses and interference results,” they concluded. “The switch matrix methodology (TMM) can be utilized sooner or later to calculate a extra correct filtered spectrum.”
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