Efficiency - Page 48

Researchers from Helmholtz-Zentrum Berlin (HZB), headed by Prof. Susan Schorr and Dr. Joachim Breternitz, have achieved a breakthrough in understanding the crystalline structure of hybrid halide perovskites. The team investigated crystalline samples of methylammonium lead iodide (MAPbI₃), the most prominent representative of this class of materials, at the Diamond Light Source synchrotron (DLS) in the United Kingdom using high-resolution single-crystal diffraction. This approach provided data for a more in-depth analysis of the crystalline structure of this material.

They were also able to clarify, whether ferroelectric effects are possible at all in this hybrid halide perovskite. Ferroelectric domains can have favorable effects in solar cells and increase their efficiency. However, measuring this effect in samples is difficult - a null result can mean that there is either no ferroelectric effect or that the ferroelectric domains cancel one another's effects out.

Rice University researchers have overcome a major hurdle standing between perovskite-based solar cells and commercialization.

Through the strategic use of the element indium to replace some of the lead in perovskites, Rice materials scientist Jun Lou and his colleagues at the Brown School of Engineering say they're better able to engineer the defects in cesium-lead-iodide solar cells that affect the compound's band gap, a critical property in solar cell efficiency.

The China-based Microquanta says its research team achieved a 14.24% conversion efficiency record for a large-area (200x800cm²) perovskite solar module. The device has reportedly passed testing by the European Solar Test Installation agency. Also, Microquanta announced a 20 MW perovskite module pilot line.

The business has focused on perovskite cell and module R&D from day one. Last year, Microquanta achieved a lab conversion efficiency record of 17.9% (17.3% stable rate) with its perovskite solar module, and the company then turned to large-area devices.

An international team of researchers, including ones from Penn State, Columbia University, University of Toledo, Northeastern University in the U.S and Carl von Ossietzky University in Germany, designed next-gen solar cells that mimic photosynthesis with a biological material, by adding the protein bacteriorhodopsin (bR) to perovskite solar cells.

Power conversion efficiency (PCE) distribution of bR-incorporated PSC based on statistics of 15 devices, with average efficiency of 16.34 %. Image from ACS article

'These findings open the door for the development of a cheaper, more environmentally friendly bioperovskite solar cell technology,' said Shashank Priya, associate vice president for research and professor of materials science at Penn State. 'In the future, we may essentially replace some expensive chemicals inside solar cells with relatively cheaper natural materials.'

Korea Electric Power Corp. (KEPCO) recently stated that it has developed a flat-type perovskite solar cell with "the world's best photoelectric conversion efficiency".

KEPRI, an R&D subsidiary of KEPCO, reportedly succeeded in producing perovskite solar cell with 20.4% photoelectric conversion efficiency, surpassing the 20.1% efficiency of flat solar cells announced so far.

A team of researchers from Stanford University and University of Colorado Boulder, led by Professor Michael McGehee, demonstrated how to dramatically improve the stability of tin-containing perovskite materials used in stacked solar cells, allowing for up to 30% power conversion efficiency.

These stacked perovskite solar cells could be an inexpensive alternative to silicon solar panels that operate at only 20% efficiency. McGehee and his team have been developing perovskite stacking methods for years in an attempt to increase power conversion efficiency.

A research team led by Prof. GAO Peng from Fujian Institute of Research on the Structure of Matter of the Chinese Academy of Sciences has developed high-performance perovskite solar cells with enhanced environmental stability.

The team reported a 2-(4-fluorophenyl)ethylamine (FPEA: 4-FC₆H₄C₂H₄NH₃) bulky cation to grow a 2D perovskite overlayer on the top of the Cs/FA/MA triple-cation 3D perovskite to combine the high stability of 2D perovskite with high efficiency of 3D perovskite simultaneously.

Researchers at Nanjing University in China and the University of Toronto in Canada have fabricated all-perovskite tandem solar cells (PSCs) with remarkable independently certified PCEs of 24.8% for small-area devices (0.049 cm²) and 22.1% for large-area devices (1.05 cm²).

Fabricating all-perovskite tandem solar cells, based on both wide-bandgap and narrow-bandgap perovskites, could lead to a higher power conversion efficiency (PCEs) than that attained by single-junction cells without increasing fabrication costs. In order to build this new type of solar cell, however, researchers need to find a way to enhance the performance of each subcell, while also integrating the wide-bandgap and narrow-bandgap cells synergistically.

Researchers from King Abdullah University of Science and Technology (KAUST) in Saudi Arabia and University of Twente in the Netherlands have developed transparent conductive films that let through a broader range of the solar spectrum, which are set to increase the power conversion efficiency of perovskite-based multijunction solar cells beyond 30%.

A comparison of the used device test structures with different silicon bottom cells. Image taken from Advanced Functional Materials

Performance of perovskite-based tandem solar cells rests on the ability of the top cell to harvest the blue portion of the solar spectrum while letting through the near-infrared light. Conversely, the bottom cell only needs to absorb near-infrared light. "The semitransparency of the top cell depends on the optical bandgap and thickness of the perovskite thin film as well as the characteristics of the transparent electrodes, especially their sun-exposed side," explains study lead Stefaan De Wolf from theKAUST Solar Center.

MIT researchers have designed perovskite photovoltaic-powered sensors that could potentially transmit data for years before they need to be replaced. To this end, the team mounted thin-film perovskite cells as energy-harvesters on inexpensive radio-frequency identification (RFID) tags.

The cells could power the sensors in both bright sunlight and dimmer indoor conditions. Moreover, the team found the solar power actually gives the sensors a major power boost that enables greater data-transmission distances and the ability to integrate multiple sensors onto a single RFID tag.