Perovskite Solar - Page 10

An international team of researchers, including ones from the University of Toronto, University of Toledo, Northwestern University, Lawrence Berkeley National Laboratory, KAUST and more, recently developed an all-perovskite tandem device that is said to show reduced recombination losses in the cell’s bottom device and excellent stability.

Image credit: Northwestern University
 

To improve the perovskite solar cell’s surface, the scientists created partially non-conductive and non-functional areas that protect the perovskite area underneath from becoming defective. The team examined the addition of diamine to improve the perovskite solar cell’s surface. The scientists found that the process made the surface more stable and improved the overall performance, resulting in a power conversion efficiency of 27.4% with better stability.

Researchers from China's Beijing Institute of Technology, Peking University, Central South University, Jiangnan University and Auner Technology have developed a unique binary 2D perovskite passivation approach and used it to fabricate a monolithic perovskite/silicon tandem solar cell with a steady-state efficiency of 30.65% (reportedly assessed by a third party). 

Schematic of the monolithic tandem structure based on a double-side textured silicon heterojunction cell. Image credit: Nature Communications

The tandem devices also retained 96% of their initial efficiency after 527 h of operation under full spectral continuous illumination, and 98% after 1000 h of damp-heat testing (85 °C with 85% relative humidity).

Scientists at Oxford University Physics Department have developed thin-film perovskite coatings that could be placed onto the surfaces of everyday objects like cars and mobile phones to generate increasing amounts of solar electricity without the use of silicon-based solar panels.

Dr Shuaifeng Hu, Post Doctoral Fellow at Oxford University Physics, holding the new thin-film perovskite material. Image credit: Martin Small and Oxford University.

The light-absorbing material is said to be, for the first time, thin and flexible enough to apply to the surface of almost any building or common object. Using a pioneering technique developed in Oxford, which stacks multiple light-absorbing layers into one solar cell, they have harnessed a wider range of the light spectrum, allowing more power to be generated from the same amount of sunlight.

Solar cells and light-emitting diodes strive to maintain the excited state kinetics of molecules. A major loss mechanism, especially in the highest efficiency systems, is called exciton-exciton annihilation, leading to lowering of solar efficiency and of light output in LEDs. Controlling the amount of exciton-exciton annihilation is therefore an important goal that affects efficiency.

National Renewable Energy Laboratory (NREL) researchers, working with researchers from University of Colorado Boulder, sought to control exciton/exciton annihilation by coupling excitons with cavity polaritons, which are essentially photons caught between two mirrors, to combat energy dissipation and potentially increase efficiency in optoelectronic devices. As detailed in their recent article, the scientists used transient absorption spectroscopy to demonstrate control of the loss mechanism by varying the separation between the two mirrors forming the cavity enclosing the 2D perovskite (PEA)₂PbI₄ (PEPI) layer. This perovskite material is a candidate for future LED applications.

Researchers from China's Jinan University, University of Macau, Wuyi University, Guangdong Mellow Energy and Germany's IEK-5 Photovoltaik (Forschungszentrum Jülich) recently designed a two-terminal perovskite-silicon tandem solar cell that utilizes new hybrid interconnecting layers to reduce recombination losses in the top perovskite device. The tandem cell achieved an impressive fill factor of 81.8%, which the scientists said is the highest value ever reported for this cell technology to date.

The team's 2T perovskite-silicon tandem solar cell is based on special hybrid interconnecting layers (ICLs) that prevent direct contact between the perovskite absorber and transparent conductive oxide (TCO). The scientists' approach is based on sputtered nickel oxide (NiOx) as the seed layer of SAMs to build the hybrid interconnecting layers. The sputtered treatment technique provides, according to the team, an easy coating on a complex substrate and high reproducibility.

Researchers from NREL, Yale University, Hong Kong Baptist University and The Hong Kong University of Science and Technology (HKUST) have designed a chiral-structured interface in perovskite solar cells, which reportedly enhances their reliability and power conversion efficiency.

Using the PSC developed by the team to power a mobile phone as a demo. Image from Techxplore, credit HKUST

The performance of PSCs still faces significant barriers to commercialization, particularly due to various stability issues under real-world conditions. A major challenge is, according to the team, the insufficient adhesion between the different layers of the cells, resulting in limited interfacial reliability. To address this issue, the team was inspired by the mechanical strength of natural chiral materials and constructed an unprecedented chiral-structured interface in PSCs, unlocking very high reliability.

The Michigan Translational Research and Commercialization Advanced Transportation Innovation Hub has awarded over $1.5 million to 15 projects driving commercial potential in transportation technologies. 

Among the recipients are Assistant Professor of Chemical Engineering Xiwen Gong, whose research addresses the challenges in the large-scale production of perovskite solar cells. Gong’s project aims to create low-cost, large-scale perovskite solar cells with high efficiency and stability needed for potential applications in the electric and hybrid vehicle and industry.

Researchers from the Chinese Academy of Sciences (CAS) posit that the efficiency and stability of perovskite modules are mainly limited by the quality of scalable perovskite films and sub-cells’ lateral contact. So, in their recent work, they addressed this by reporting constant low temperature substrates to regulate the growth of perovskite intermediate films to slow down the crystallization process. This is meant to assist in obtaining high-quality homogeneous perovskite films in large scale size, which avoid the effect of the ambient temperature on the film quality. 

Schematic diagram of the fabrication process of perovskite films using low-temperature substrate growth (LTSG). Image from Nature Communications

In addition, a scribing step named P1.5 was added before the top function layers deposition, so the diffusion barrier layer can be formed “naturally” at the interconnection interface without introducing any additional materials, which alleviates the diffusion degradation process. 

Researchers from Pakistan's University of Agriculture Faisalabad, University College of London United Kingdom and The National University of Malaysia have conducted a series of simulations to investigate how a cadmium telluride buffer layer (BL) may help increase efficiency and stability in perovskite solar cells. Their experiment showed that cell efficiency may climb from 11.09% to 23.56%.

Solar cell architecture with BL. Image credit: Results in Engineering

The researchers explained that the presence of a BL in a perovskite cell offers a porous structure that aids in forming the upper hole-transporting layer (HTL), while also preventing the leakage of corrosive additives from the HTL material. “The improvement in the development of HTM layer not only promotes efficient hole transfer and conduction but also restricts charge recombination,” they explained.

SolaEon Technology, a Chinese solar manufacturer, claims that it has achieved a record conversion efficiency of 21.95% on 300mm x 400mm monolithic perovskite tandem solar cells for MPPT.

In October 2023, SolaEon claimed its 1,200 sq. cm. perovskite single-junction solar cell module achieved a 3rd party certified efficiency of 21.63%. In April 2024, SolaEon said its perovskite solar cell module achieved a steady state efficiency of 19.2% based on 1,027.1 c㎡ area. In May 2024, it reportedly achieved a world record conversion efficiency of 29.34% for monolithic full perovskite tandem solar cells.