Researchers from Australia's Griffith University and Queensland University of Technology have reported the fabrication of planar carbon-based perovskite solar cells (c-PSCs) with high efficiency and excellent stability, by employing electrochemically produced large-area phosphorene flakes as a hole-transporting layer (HTL). 

Carbon-based perovskite solar cells have attracted increasing attention due to their many advantages, including: ease of fabrication, the potential of assembling flexible devices, low manufacturing costs and more. However, c-PSCs suffer from limited hole extraction and high charge carrier recombination due to inadequate interface contact between the carbon electrode and perovskite film.

MIT researchers have developed a new computer vision technique that significantly speeds up the characterization of newly synthesized electronic materials. The technique automatically analyzes images of printed semiconducting samples and quickly estimates two key electronic properties for each sample: band gap and stability.

Overview of the synthesis and characterization pipeline for perovskite semiconductors. Image credit: Nature Communications

The new technique reportedly characterizes electronic materials 85 times faster compared to the standard benchmark approach. The researchers intend to use the technique to speed up the search for promising solar cell materials. They also plan to incorporate the technique into a fully automated materials screening system.

Researchers from Australia's Monash University and CSIRO Manufacturing have reported a lamination technique, known as cold isostatic pressing (CIP), to build a perovskite solar cell based on a flexible bilayer electrode made of carbon and silver. The resulting electrode can reportedly compete with gold-carbon electrode based counterparts in terms of efficiency and stability.

The back side of a C-PSC with a custom-designed electrode after CIP processing. Image credit: Communications Materials

The researchers, led by CSIRO Manufacturing, which is part of Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), explained that while perovskite solar cells (PSCs) with evaporated gold (Au) electrodes have shown promising efficiencies, the maturity of the technology still demands low-cost and scalable alternatives to progress towards commercialization. Carbon electrode-based PSCs (C-PSCs) represent a promising alternative, however, optimizing the interface between the hole transport layer (HTL) and the carbon electrode without damaging the underlying functional layers is a persistent challenge, which the team set out to address.

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Cygnus 2 is a high-resolution controller capable of controlling six independent rates as low as 0.1 Å/s, typical of advanced solar cell manufacturing processes. This is especially useful in the OLED and solar markets as it eliminates the need for multiple controllers for tools with multiple sources. Instead of having six different deposition controllers for each chamber, one Cygnus 2 can control all six sources independently, simultaneously, or in any combination that is desired to minimize integration cost. 

Researchers from the University of North Carolina at Chapel Hill, Colorado School of Mines, National Renewable Energy Laboratory (NREL), University of Toledo and University of California San Diego have pointed out that the light-emitting diodes (LEDs) used in indoor testing of perovskite solar cells do not expose them to the levels of ultraviolet (UV) radiation that they would encounter in actual outdoor use. 

The scientists reported degradation mechanisms of p-i-n–structured perovskite solar cells under unfiltered sunlight and with LEDs. Weak chemical bonding between perovskites and polymer hole-transporting materials (HTMs) and transparent conducting oxides (TCOs) reportedly dominate the accelerated A-site cation migration, rather than direct degradation of HTMs.

Researchers from the Ningbo Institute of Materials Technology and Engineering at the Chinese Academy of Sciences recently reported a novel perovskite/silicon tandem solar cell based on flexible ultrathin silicon, with a thickness of about 30 µm.

Despite major progress in the efficiency of rigid perovskite/silicon tandem solar cells, flexible perovskite/silicon tandem solar cells have remained elusive. The team explains that this is due to the challenge of enhancing light absorption in ultrathin silicon bottom cells while maintaining their mechanical flexibility.

Researchers at China's Hangzhou Dianzi University have modified the absorber of a conventional perovskite solar cell with potassium trifluoromethanesulfonate (KTFS) and found that the additive improved the device's performance and stability. The cell’s perovskite film reportedly showed less lead defects and lower J-V hysteresis.

“The KTFS molecule is a typical kind of potassium salt including the cationic potassium (K⁺) and anionic trifluoromethanesulfonate (SO3CF3−), indicating a bifunctional interaction between KTFS and perovskite,” the team explained. “The sulfonyl group can passivate the undercoordinated lead of the deep-level defect and thus inhibit the non-radiative recombination.”

Researchers from Purdue University and ShanghaiTech University have developed a patent-pending method to synthesize high-quality, layered perovskite nanowires with large aspect ratios and tunable organic-inorganic chemical compositions.

The novel method creates layered perovskite nanowires with exceptionally well-defined and flexible cavities that exhibit a wide range of unusual optical properties beyond conventional perovskites.

Researchers at City University of Hong Kong (CityU) have presented a novel material design strategy and simple device-manufacturing process for skin-conformable perovskite-based alternating-current electroluminescent (PeACEL) devices. 

Working mechanism of the PeACEL device. Image credit: Nature Photonics

These devices exhibit a narrow emission bandwidth (full-width at half-maximum, <37 nm), continuously tunable emission wavelength (468–694 nm), high stretchability (400%) and adequate luminance (>200 cd m−2). 

Tokyo Chemical Industry (TCI), a global supplier of laboratory chemicals and specialty materials, is offering surface treatment reagents for perovskite solar panels. The company says that using its DMPESI materials, solar panel producers can realize superior device stability.

Figure, Perovskite solar cell device structure and comparison of solar cell performance using DMPESI

TCI's DMPESI materials offer strong bonding ability to perovskite surface, much higher than PEAI. The materials suppress the phase transition of FAPbI3 from α phase to δ phase. Thanks to the suppression of ion migration and the influence of the external atmosphere, the materials improve device stability even under high temperature and humidity.

Contact TCI now for more information on its DMPESI reagents.