Transparency - Page 3

An international research group has designed a semi-transparent perovskite solar cell that reportedly shows an improved open-circuit voltage and fill factor thanks to plasmonic enhancement.

The technique is based on the enhancement of the cell's electromagnetic field through metal nanostructures, which improves the device's low optical absorption in the visible spectrum. The research team designed the tech with applications in building-integrated photovoltaics (BIPV) in mind, but it can also be suitable for automotive and smart glasses.

Solliance partners TNO, imec/EnergyVille and the Eindhoven University of Technology, have reported a 18.6% efficient highly near infrared transparent perovskite solar cell. When combined in a four terminal tandem configuration with an efficient Panasonic crystalline silicon (c-Si) cell or with a Miasolé flexible CIGS cell, the configuration delivered new record power conversion efficiencies of 28.7% and 27.0%, respectively.

The researchers explained that four terminal tandems allow to build on experience and practices already available in the industry. In addition, four terminal perovskite/c-Si tandems can be applied broadly and are, for example, very beneficial in combination with bifacial c-Si solar cells which, depending on the actual albedo, can readily achieve a total power generation density as high as 320 W/m².

Scientists from South Korea have developed a foldable thin-film device with promising characteristics. Integrating a perovskite cell material and a carbon nanotube electrode, the group fabricated a device that achieved 15.2% efficiency and could be folded more than 10,000 times at a bending radius of 0.5mm.

Solar cell materials tend to be quite sensitive. Designing and manufacturing devices that can withstand the stress of being folded and bent is challenging, and many of even the most promising solutions are still quite limited in their flexibility. The scientists at Pusan National University in South Korea took a major step forward in solving this problem, fabricating a device that can be folded down to a 'bending radius' ' the minimum size of fold possible without causing damage ' of 0.5mm.

A new EU project called "CITYSOLAR" aims to revolutionize the market for transparent solar cells for windows by combining two photovoltaic (PV) technologies in a tandem configuration. The project has received 3,779,242 EUR in support from the H2020 framework programme. Transparent solar cells for windows have been known for several years, but are still not sufficiently efficient - which is what the new project will attempt to change.

'We develop new innovative concepts within light management and solar module integration that are specifically targeted at new promising organic and hybrid thin film PV technologies, and by that we go significantly beyond state-of-the-art in terms of efficiency for transparent photovoltaics. It's a revolutionary new concept,' says Professor Aldo di Carlo, Cnr-Ism, who is coordinator of the new project and is thrilled about the support of "CITYSOLAR" from the H2020 framework.

Researchers from the Shaanxi Normal University in China have designed a perovskite solar cell based on methylammonium lead iodide (MAPbI₃) through a dual passivation technique that simultaneously passivates trap defects in both the perovskite and electron transport layer (ETL) films.

'So far, most techniques for modifying perovskite solar cells focus on either the perovskite or electron transport layer,' the research group reported, noting that the ETL must have decent optical transmittance and high electron mobility to extract photo'induced carriers and contribute to the solar cell efficiency.

A research team, led by University of Minnesota Professor K. Andre Mkhoyan, has made a discovery that blends the best of two sought-after qualities for touchscreens and smart windows'transparency and conductivity.

The atomic arrangement of both the BaSnO3 crystal and the metallic line defect. Image credit UMN

The researchers have observed metallic lines in a perovskite crystal. Perovskites are abundant in the Earth's center, and barium stannate (BaSnO₃) is one such crystal. However, it has not been studied extensively for metallic properties because of the prevalence of more conductive materials like metals or semiconductors. The finding was made using advanced transmission electron microscopy (TEM), a technique that can form images with magnifications of up to 10 million.

Energy Materials Corporation (EMC), developer of high-speed roll-to-roll manufacturing of solar energy panels, recently announced that it has developed an enabling process to print transparent conductors as part of the scale-up of its inline manufacturing process.

Roll-to-roll printing of metal conductors on Corning Willow Glass (flexible glass) at 60 meters per minute reportedly sets a world speed record for printing flexible electronics on glass. The process surpasses the company's goal of achieving less than 5% loss in the transmission of light though the conductive layer.

An international group of researchers, led by the University of Padova in Italy, has designed a hole extraction layer with water-splitting additives to reduce the impact of moisture in perovskite solar devices. They reported that the method ensured a power conversion efficiency of more than 9% in perovskite cells stored for a month in a water-saturated atmosphere.

There is an ongoing search for moisture stability in perovskite solar cells (PSCs), as protecting the perovskite layer from moisture is key to preventing excess water from forming on the layer itself and affecting overall performance. The new proposed solution to this issue integrates water-splitting (WS) hydrophobic layers to the perovskite absorber of a standard perovskite cell. The ancillary layers can purportedly convert incoming water into oxygen and hydrogen.

The Emerging PV Reports Initiative (EPVRI) is a new academic international framework for collecting, presenting and analyzing data about the best achievements in the research of emerging photovoltaic materials, e.g., organic, perovskite and dye sensitized solar cells, among others. The new database for collecting, displaying, and analyzing the performance of emerging photovoltaic technologies was spearheaded by researchers in a worldwide international consortium: the Emerging PV Reports initiative.

In order to provide an up-to-date and easy-to-access platform with a global scope, the Emerging PV initiative was established by a consortium of experienced academic researchers from more than 15 countries, all of whom are experts in new and emerging photovoltaic research directions.

Energy Materials Corporation (EMC) has stated its plans for roll-to-roll printing of perovskite PV on glass.

The plan is backed by two partnerships, one with the Eastman Kodak Company for roll-to-roll printing and another with glass and ceramics company Corning, for flexible glass. EMC's funding includes a $4 million research grant from the Solar Energy Technologies Office of the U.S. Department of Energy.