CdTe breakthrough might lead to more reliable solar cells, UK scientists say

Aug 24, 2021 02:21 PM ET
  • New insight into exactly how chlorine improves the efficiency of cadmium telluride (CdTe) cells could result in also higher performances, according to a group of researchers at Loughborough University in the UK.
CdTe breakthrough might lead to more reliable solar cells, UK scientists say
Image: First Solar

The group is aiming to understand the role of chlorine in both boosting cell performance as well as additionally in eliminating defects referred to as stacking faults.

A previous study from the group showed that grain borders, where crystals of various orientation join together, are responsible for bad cell efficiency. These grain boundaries have problems that can function as catches for electrons, making these areas 'energetic'.

In a procedure called passivation, the scientists showed chlorine can shut down several of the catches and make the grain boundaries less energetic-- consequently increasing the effectiveness of CdTe.

While the missing out on piece was claimed to be understanding just how the stacking faults vanish, the new research shows that if there is enough chlorine in the grain borders, a waterfall mechanism is set off that structurally removes these stacking faults.

" Although the piling faults' loss is not what causes the enhanced performance, if they have actually disappeared then that is the signal that the CdTe cell is mosting likely to have excellent performance. This has never been revealed prior to," claimed Loughborough University's Dr Pooja Goddard.

She claimed the following step will certainly be to see how further improvements can be made by taking a look at doping the CdTe with various other aspects to promote effectiveness above 25%. "Each tiny gain in effectiveness implies the modern technology is ending up being much more affordable versus the current silicon innovation."

More than 25GW of CdTe modules have been set up around the world, according to Loughborough University, which stated the modern technology has the possible to be affordable on effectiveness but at a reduced manufacturing cost than silicon-based modules.

Without treatment CdTe has extremely reduced effectiveness and is generally around only 1%. Nonetheless, when CdTe modules go through a chlorine therapy-- which involves treating CdTe with cadmium chloride at 420oC for 20 mins-- their effectiveness jumps substantially.

The document performance for a laboratory CdTe solar cell is 22.1% and also was attained by First Solar back in 2016. The US-based supplier last year delivered 5.5 GW of its CdTe thin movie modules as well as is presently broadening its footprint with a brand-new module manufacturing facility in Ohio.

The United States National Renewable Energy Laboratory lately secured funding from the nation's Department of Energy (DOE) to establish a consortium that will certainly intend to scale up domestic CdTe module manufacturing, accomplish cell efficiencies above 26% and lower module expenses to listed below US$ 0.15/ watt. According to the DOE, CdTe thin movie technologies make up 20% of the modules installed in the United States.

A collaboration last year in between DSM Advanced Solar as well as independent power manufacturer SolarKapital attained a 4% energy gain at a 500kWp PV nuclear power plant in Germany by deploying DSM's anti-reflective layer innovation on First Solar's CdTe modules.

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