Efficiency - Page 54

An international research group reported boosting the efficiency of perovskite solar cells by adding silicon nanoparticles. Silicon particles do not absorb light, nor do they interact with other materials in the cell, according to ITMO University in St. Petersburg, which worked with St. Petersburg State University and scientists in Italy and the USA.

'Dielectric particles don't absorb light, so they don't heat up,' said ITMO researcher Aleksandra Furasova. 'They are chemically inert and don't affect the stability of the battery. Besides, being highly resonant, such particles can absorb more light of a wide range of wavelengths. Due to special layout characteristics, they don't damage the structure of the cells. These advantages allowed us to enhance cells efficiency up to almost 19%. So far, this is the best-known result for this particular perovskite material with incorporated nanoparticles'.

Researchers from The Photovolatic and Optoelectronic Device Group at Oxford University have shown that perovskite-based concentrator photovoltaic devices (CPVs) may solve the issue of prohibitively high production costs while providing devices that perform comparably to commercialized silicon-based devices.

The devices are based on metal halide perovskites. The Oxford researchers, led by Henry Snaith, focused their search on a material that would be stable under high irradiance, and found the mixed-halide perovskite Fa0.83Cs0.17PbI2.7Br0.3 fit them best. The group found that their devices, when cooled constantly to maintain close to room temperature, retained 90% of their original efficiency after 150 hours spent under 10 Suns (10 kW/m2) of concentrated light.

UCLA researchers have recently reported a highly efficient thin-film solar cell with a double-layer design that converts 22.4% of the incoming energy from the sun. The device is made by spraying a thin layer of perovskite onto a commercially available solar cell. The solar cell that forms the bottom layer of the device is made of a compound of copper, indium, gallium and selenide, or CIGS.

The performance was reportedly confirmed in independent tests at the U.S. Department of Energy's National Renewable Energy Laboratory. The UCLA device's efficiency rate is similar to that of the poly-silicon solar cells that currently dominate the photovoltaics market.

Researchers from Lahore University and Benha University have proposed an interesting configuration of combination of solar materials that can possibly boost total electricity output by 10-30% ' reportedly reaching between 30-36% efficiency.

(a)bifacial per/Si double-tandem cell (b)standalone bifacial single-tandem cell (c)PVK cell (d)Si heterojunction with intrinsic thin layer solar cell

The researchers describe the cell: "a 3-T, four-junction perovskite/silicon double-tandem (PSDT) solar cell structure that can efficiently harvest light in all ranges of albedo by stacking two tandem perovskite/silicon cells in a flipped configuration with a common (middle) terminal".

Researchers from Arizona State University's Fulton Schools of Engineering have calculated that a 32% efficient perovskite-silicon tandem cell could produce electricity at the same price as cutting-edge 22% efficient panels in the most cost-competitive of situations.

The paper specifies: '…a large cost benefit will not necessarily be needed to prefer tandem systems over single-junction systems, because higher efficiencies bring additional perceived benefits such as reduced installation area. It is, however, necessary that the path leading to such a tandem be continuously profitable.'

A team of researchers from the University of Potsdam and HZB has identified loss processes in perovskite solar cells that limit their efficiency, and found that the most significant efficiency losses occur at the interface between the perovskite and transport layer.

In certain defects in the crystal lattice of the perovskite layer, charge carriers (i.e. electrons and "holes") that have been released by sunlight can recombine again and thus be lost. But whether these defects were located within the perovskite layer or at the interface between the perovskite layer and the transport layer was unclear until now.

Researchers at the University of Washington report that a prototype perovskite thin-film has performed even better than today's best solar cell materials at emitting light. 'It may sound odd since solar cells absorb light and turn it into electricity, but the best solar cell materials are also great at emitting light,' said co-author and UW chemical engineering professor Hugh Hillhouse. 'In fact, typically the more efficiently they emit light, the more voltage they generate.'

a back-reflector A back-reflector surface used to test perovskite performance. Each quadrant is a different surface material ' gold, titanium, palladium or a silica compound ' upon which the perovskite material would be deposited for experiments

The UW team achieved a record performance using a lead-halide perovskite, by chemically treating it through a process known as 'surface passivation,' which treats imperfections and reduces the likelihood that the absorbed photons will end up wasted rather than converted to useful energy.

Imec, the leading research and innovation hub in nanoelectronics, energy and digital technology, within the partnership of EnergyVille, announced a record result for its 4-terminal perovskite/silicon tandem photovoltaic cell. In fact, with a reported power conversion efficiency of 27.1%, the new tandem cell tops the most efficient standalone silicon solar cell. Further careful engineering of the Perovskite material will bring efficiencies over 30% in reach.

Imec's new record tandem cell uses a 0.13 cm² spin-coated perovskite cell developed within the Solliance cooperation, stacked on top of a 4 cm² industrial interdigitated back-contact (IBC) silicon cell in a 4-terminal configuration, which is known to have a higher annual energy yield compared to a 2-terminal configuration. Additionally, scaling up the tandem device by using a 4 cm² perovskite module on a 4 cm² IBC silicon cell, a tandem efficiency of 25.3% was achieved, surpassing the stand-alone efficiency of the silicon cell.

New Energy and Industrial Technology Development Organization (NEDO) and Toshiba have announced the world's largest film-based perovskite photovoltaic module. The module is 703cm² (24.15 x 29.10cm) and achieves a power conversion efficiency (PCE) of 11.7%, overcoming the difficulties of increasing size and efficiency at the same time.

The module was developed using the meniscus printing technology owned by Toshiba and a newly developed printing process. Toshiba developed the printing process for a larger module by controlling the chemical reaction between PbI₂ and MAI on the substrate, using the ink composition as a mechanism. The company has also improved the uniformity of the layer thickness and increased the homogeneity of the crystal layer properties over a larger area, by controlling the process and adjusting the perovskite crystal growth conditions during the printing process. As a result, a PCE of 11.7% has been obtained on a module with an area of 703cm², almost as large as 900cm², the practical a scale.

Microquanta Semiconductor has announced reaching "a new world record of 17.3% conversion efficiency for perovskite solar mini-module under newly established testing protocols for perovskite devices". This result was reportedly certified by the international test center Newport Corp.

Under these new protocols, the stabilized 17.3% efficiency rating was for a 7-cell perovskite solar module with designated illumination area of 17.277 cm². The best device reached an even higher number of 17.9% with conventional testing methods. The desired efficiency was achieved by further optimizations of perovskite materials and manufacturing processes. This is the company's fourth continuous breakthrough regarding efficiency of perovskite solar modules and the first one under new internationally accepted protocols. Since 2017, Microquanta had pushed the efficiency record up from 15.2% to 16%, and then to above 17% before this new accomplishment.