Formamidinium lead iodide is a very good material for photovoltaic cells, but getting the correct and stable crystal structure is a challenge. The techniques developed so far have produced rather poor results. However, University of Groningen scientists, led by Professor of Photophysics and Optoelectronics Maria Antonietta Loi, have now cracked it – using a blade and a dipping solution.
The results were published in the journal Nanoscale on 15 March 2019.
Formamidinium lead iodide (FAPbI3) is a perovskite, a crystal with a distinctive structure. Perovskites are named after a mineral that has the chemical formula ABX3. In an idealized cubic unit cell, the X position is occupied by anions that form an octahedron with a central cation in the B position while the corners of the cube are occupied by the A position cations (see picture).
‘This formamidinium lead iodide material has very good characteristics, but the A position formamidinium ion causes instability in the structure,’ explains Loi. 3D films made from this material most often turn out to be a mixture of a photoactive and a photoinactive phase, the latter being detrimental to the final application. Loi therefore set her PhD student Sampson Adjokatse to work to find a solution.
After trying different strategies, he found one that worked. ‘And most importantly, one that is scalable and could be used for industrial production,’ says Loi. After all, solar cells must be produced in large panels and it is very important to find a good and cheap technique to do so.
Adjokatse started with a different perovskite, in which the formamidinium was replaced by a larger 2?phenylethylammonium molecule, and in doing so formed a 2D perovskite. This material was deposited as a thin film using the ‘doctor-blade’ technique, related to techniques widely used in industrial processes such as printing.
‘Basically, you spread the material onto a substrate using a blade,’ explains Adjokatse. The blade can be set to produce a film with a thickness of around 500 nanometres, creating the 2D perovskite layer. ‘The important point is that these films are very smooth with large crystalline domains of up to 15 micrometres,’ says Adjokatse. The smooth 2D films based on 2-phenylethylammonium lead iodide were used as a template to produce 3D formamidinium lead iodide films.
This was achieved by dipping the 2D film in a solution containing formamidinium iodide. This resulted in the growth of a 3D film through ‘cation exchange’, where formamidinium took the place of 2?phenylethylammonium. ‘These films show much higher photoluminescence compared to reference 3D formamidinium lead iodide films and show increased stability when exposed to light or moisture,’ says Loi. ‘This means that we now have a method for the production of high-quality films for perovskite solar cells using an industrially scalable technique.’
Learn more: Making solar cells can be like buttering bread
The Latest on: Perovskite solar cells
via Google News
The Latest on: Perovskite solar cells
- Plants absorb lead from perovskite solar cells more than expectedon February 21, 2020 at 5:05 pm
Certain perovskite compounds are seen as a great hope for better and, above all, even cheaper solar cells. Their crystal lattice is formed by organic methylammonium cations (MA+) surrounded by heavy ...
- A prenucleation strategy for ambient fabrication of perovskite solar cells with high device performance uniformityon February 21, 2020 at 2:15 am
Consequently, we are able to obtain a compact and uniform perovskite layer, which affords high efficiency perovskite solar cells. More excitingly, the solar cells show high performance uniformity, ...
- Scientists develop safer lead-based perovskite solar cellon February 19, 2020 at 8:42 pm
DeKalb, Ill. -- Researchers at Northern Illinois University and the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) in Golden, Colorado, are reporting today (Feb. 19) in ...
- Researchers Improve Safety of Lead-Based Perovskite Solar Cellson February 19, 2020 at 9:14 am
Golden, CO, Feb. 19, 2020 (GLOBE NEWSWIRE) -- Researchers at the National Renewable Energy Laboratory (NREL) and Northern Illinois University (NIU) have developed a technique to sequester the lead ...
- On-device lead sequestration for perovskite solar cellson February 19, 2020 at 9:10 am
All prices are NET prices. VAT will be added later in the checkout. Rent or Buy article Get time limited or full article access on ReadCube.
- New Breakthrough Makes Solar Cells More Durableon February 16, 2020 at 10:00 am
The Brown study found that the use of perovskite materials (“a broad class of crystalline materials”) can create a much more resilient and durable next generation of solar cells. Science Daily ...
- Cracks in perovskite films for solar cells easily healed, study findson February 12, 2020 at 1:49 pm
A new study reveals good news for the possibility of using perovskite materials in next-generation solar cells. The study, published in the journal Acta Materialia, finds that though perovskite ...
- A little heat can fix cracks in perovskite filmson February 12, 2020 at 12:45 pm
That bodes well for the possibility of using inexpensive, but fragile, perovskite materials to replace or complement pricey silicon in solar cell technologies, researchers say. “The efficiency of ...
- Cracks in perovskite films for solar cells easily healed, study findson February 12, 2020 at 10:52 am
PROVIDENCE, R.I. [Brown University] -- A new study reveals good news for the possibility of using perovskite materials in next-generation solar cells. The study, published in the journal Acta ...
- Hunt Achieves Key Milestone In Perovskite Technology Developmenton February 12, 2020 at 7:34 am
Hunt Energy announced today that its solar technology company, Hunt Perovskite Technologies (HPT), has achieved an industry-leading milestone in the development of a highly-durable perovskite ...
via Bing News