Efficiency - Page 13

Researchers from the Korea Institute of Energy Research (KIER), Korea Research Institute of Standards and Science, Jusung Engineering and the Jülich Research Center have reported an advancement in the stability and efficiency of semi-transparent perovskite solar cells.

The semi-transparent solar cells achieved an impressive efficiency of 21.68%, which is said to be the highest efficiency to date among perovskite solar cells that use transparent electrodes. Additionally, they showed remarkable durability, with over 99% of their initial efficiency maintained after 240 hours of operation.

Researchers at the Karlsruhe Institute of Technology (KIT), Institute for Solar Energy Research Hamelin (ISFH) and Leibniz University Hannover have designed triple-junction perovskite–perovskite–silicon solar cells with a record power conversion efficiency of 24.4%. 

Schematic of the solar cell. Image from Energy & Environmental Science

Optimizing the light management of each perovskite sub-cell (∼1.84 and ∼1.52 eV for top and middle cells, respectively), the team maximized the current generation up to 11.6 mA cm⁻². Key to this achievement was the development of a high-performance middle perovskite sub-cell, employing a stable pure-α-phase high-quality formamidinium lead iodide perovskite thin film (free of wrinkles, cracks, and pinholes). This enabled a high open-circuit voltage of 2.84 V in a triple junction. Non-encapsulated triple-junction devices retain up to 96.6% of their initial efficiency if stored in the dark at 85 °C for 1081 h.

Lead-halide perovskites hold great promise as the next generation of PVs, but unstable lead exposure through gas, water, and soil accumulation could have detrimental consequences if not properly controlled and recycled as perovskite use expands globally. There are also stability issues limiting operational lifetime for lead-perovskite devices themselves. Researchers have attempted to replace lead with slightly less toxic tin, but thus far tin-based perovskites still suffer from air instability. Without breakthroughs in stability and environmental safety, scaling perovskite solar technology could flood our waste stream with hazardous materials. Now, researchers from CHOSE (Centre for Hybrid and Organic Solar Energy) at the University of Rome Tor Vergata have addressed the concerns regarding toxicity and recyclability associated with the lead contained in perovskite solar cells. 

Image credit: ACS Energy Letters 

The scientists may have found a solution in a new lead-free antimony-based perovskite solar cell design. Their recent research demonstrates a mixed-cation perovskite-inspired material (PIM) that boosted efficiency by 81% compared to conventional cesium-only antimony solar cells, while also exhibiting unmatched stability.

Researchers at the University of North Carolina at Chapel Hill and CubicPV have developed mini solar modules based on perovskite cells treated with zinc trifluoromethane sulfonate [Zn(OOSCF₃)₂]. The scientists found that using a small amount of this zinc salt in the perovskite solution can address the issue of interstitial iodides, which are the most critical type of defects in perovskite solar cells that limits efficiency and stability. The zinc salt helps control the iodide defects in resultant perovskites ink and films. 

The scientists explained that this is a low-cost material that is used as an additive at a very small percentage in perovskite inks and that its use makes perovskite module fabrication more reproducible, which helps to also make it cheaper.

Researchers from Japan's National Institute for Materials Science (NIMS) and Hokkaido University have designed an inverted “n-i-p” perovskite solar cell with a new bond/charge regulated defect passivation technique, enabled by introducing bifunctional molecules onto the perovskite absorber. The device exhibited a low open circuit voltage deficit and impressive stability.

The newly-fabricated solar cell with was based on a perovskite material that doesn't contain methylammonium (MA) molecules. These molecules have intrinsic thermal instability and contribute to increasing the typical thermal instability of perovskite PV devices.

The DIAMOND project aims at developing ultra-stable, highly-efficient and low-cost perovskite photovoltaics with minimized environmental impact, promising stabilities far beyond all previous achievements of photovoltaic solar cells.

It was launched in October 5^th, 2022, and is planned to continue until November 30^th, 2025. 

Ulsan National Institute of Science and Technology (UNIST) researchers have developed solar cells using narrow bandgap organic cation-based perovskite-based quantum dots (PQDs) and demonstrated substantially higher efficiency compared with their inorganic counterparts. 

The team stressed that research to this point has predominantly focused on inorganic cation PQDs despite the fact that organic cation PQDs have more favorable bandgaps. However, the recent study unveiled a novel ligand exchange technique, that enables the synthesis of organic cation-based PQDs, ensuring exceptional stability while suppressing internal defects in the photoactive layer of solar cells.

A research team from the Fraunhofer Institute for Solar Energy Systems ISE has reported a PV module using perovskite silicon tandem solar cells from Oxford PV with an efficiency of 25% and an out-put of 421 watts on an area of 1.68 square meters, stating it is a record efficiency for a silicon perovskite tandem solar module in industrial format. 

For the manufacturing process, the researchers used equipment at Fraunhofer ISE's Module-TEC that is already used in mass production and optimized the processes for the tandem technology.

A research team, led by Northwestern scientists, has developed a method that could moves perovskite solar cells closer to industry adoption and widespread use. Using liquid crystals that can respond to temperature change and avoid accumulating precipitation, the group enabled the protection of large-area perovskite films. 

This approach led to a 22% efficiency and a stabilized efficiency of 21% for solar modules with enhanced damp heat (85% relative humidity at 85 degrees Celsius) stability and a size of 31 sq. centimeters.

Researchers from King Abdullah University of Science and Technology (KAUST), Princeton University, Marmara University, Academy of Sciences of the Czech Republic and Nano-C have designed a perovskite-silicon tandem solar cell with a top inverted perovskite cell relying on an electron transport layer (ETL) made of thermally evaporated buckminsterfullerene (C60).

In the “p-i-n” device structure, hole-selective contact p is at the bottom of intrinsic perovskite layer i with electron transport layer n at the top. Conventional halide perovskite cells have the same structure but reversed – a “n-i-p” layout. In n-i-p architecture, the solar cell is illuminated through the electron-transport layer (ETL) side; in the p-i-n structure, it is illuminated through the hole‐transport layer (HTL) surface.