From tandem cell to double absorber for 34.45% performance

• Researchers in the United States theorize that a 'double absorber' cell comprising 2 energetic thin-film layers within one cell stack can achieve impressive efficiencies, whilst removing a lot of the obstacles intrinsic to the style of tandem cells. For now however, it's only on paper.

Tandem cells have been a hot subject amongst PV researchers for a number of years now, and also are concerned by numerous as 'the future of solar cell innovation'. Yet we are still yet to see business tools comprising this innovation, and also while perovskite-silicon is in the lead, there is a range of different gadget frameworks vying for the attention of researchers.

One usual concern among those working on tandem cell designs is whether a two-terminal or a four-terminal style is the far better option. In a two-terminal set up the cells can limit each other's performance otherwise very carefully 'tuned' per various other, while a four-terminal device would certainly call for more complex wiring to take care of each cell independently. Essentially there is an integral complexity to tandem gadgets, as well as the question is whether to manage this within the cell or at the module level.

Scientists led by Pennsylvania State University in the U.S., however, suggest a various strategy that might get rid of a lot of this complexity. In a paper published in Applied Physics Letters, they theorize that piling 2 absorber layers into one cell, as opposed to piling two full cells on top of each other, might lead to both remarkable performance achievements as well as low manufacturing prices.

For such a gadget to work, both absorber layers need to have rather a comparable structure. The group at Penn State designed such a device incorporating both copper-indium-gallium-selenide (CIGS) and also copper-zinc-tin-sulfide/ selenide (CZTS) layers into one cell, noting that these 2 products have a comparable lattice structure and can be transferred making use of the very same vapor deposition strategies. Their optoelectronic designs showed that with optimization of bandgaps in both layers, such a tool could achieve 34.45% efficiency.

For now however, this is only a theory. The group brought its modeling based upon a perfect CZTS cell calculated to have 21.74% performance--, which could be referred to as a little positive contrasted to what has thus far been achieved with this material at the lab scale.

" Fabrication of this double-absorber thin-film solar cell, or an approximative alternative thereof, will certainly call for the attention of experimentalists for cautious compositional grading and also may not perform along with forecasted by a detailed optoelectronic design," the team ends. "Nevertheless, this solar cell is guaranteeing for ubiquitous in-device microwatt-scale generation of electrical energy."