Screen-printed heterojunction solar cell with 20.48% performance

• Researchers from the United States have utilized new passivated get in touch with styles to show a screen-printed silicon heterojunction solar cell on 40 micron thick standalone wafers.

A study team from the Solar Power Laboratory of the Arizona State University case to have shown a screen printed 40 micron thick silicon heterojunction solar cell, with an efficiency of 20.48%.

The cell, described in the paper Improving surface area passivation on really thin substratums for high efficiency silicon heterojunction solar cells, published in Solar Energy Materials as well as Solar Cells, is based upon an optimized thin intrinsic hydrogenated amorphous silicon layer, which is transferred onto the wafer via a brand-new speculative treatment.

The scientists initially produced silicon heterojunction samples on 200 micron thick n-type Czochralski wafers, which was then decreased to 40 μm making use of a potassium hydroxide (KOH) remedy. The examples were textured through alkaline damp etching, followed by an acidic cleaning process. "A three-chamber plasma-enhanced chemical vapor deposition (PECVD) collection device was utilized to deposit 6-- 15 nm thick intrinsic and n/p-doped hydrogenated amorphous silicon (a-Si: H) layers, forming a p-i/c-Si/i-n stack," the research study team discussed. "The p-i stack was first transferred on one side of the wafer followed by the i-n pile beyond."

The a-Si: H layer was treated with an in-situ hydrogen plasma to boost chemical passivation. Indium tin oxide (ITO) was transferred on both the cell's front as well as rear surface areas making use of a sputtering strategy, as well as a silver get in touch with was sputtered on the rear side. Still, front contacts were display printed with silver paste. The tool was then annealed for 30 min at 200 levels Celsius.

According to the group, this process generated a thicker intrinsic a-Si: H layer, which is stated to deliver better surface area passivation leading to higher minority provider lifetime as well as open circuit voltage. This is accomplished by a boosted diffusion of hydrogen to the intrinsic a-Si: H/c-Si-interface, which subsequently boosts the surface passivation.

" In this work, a bilayer of intrinsic a-Si: H was developed by first transferring a 6 nm of inherent a-Si: H, complied with by hydrogen plasma, and also lastly a 7 nm of inherent a-Si: H was transferred," the scientists said. "The ideal performance on a 40 ± 2 micron thick wafer utilizing the maximized procedure and SiOx: ITO ARC pile was 20.48%.".

According to the group, the open-circuit voltage of the cell boosts with a rise of intrinsic a-Si: H density and suggested voltage at maximum power as well as open circuit boosted by approximately 21 mV and also 8 mV, specifically. "We successfully demonstrated experimentally the potential to exceed 21% effectiveness using screen published 40 micron thick silicon heterojunction solar cells," they wrapped up.