Novel ETL shows promise for efficient and stable perovskite solar cells

Researchers from the Chinese Academy of Sciences (CAS) and Fuzhou University have reported a perovskite solar cell with an electron transport layer (ETL) based on Tin(IV) oxide (SnO2) and crystalline polymeric carbon nitrides (cPCN).

The team explained that the modification of the SnO2 layer with the cPCN is key to avoiding undesirable current-voltage hysteresis, which is responsible for reducing the cell's stability. This phenomenon tends to occur in electrical systems when current or voltage changes and the effects of the changes are delayed. It is dependent on the composition of the material, and ion migration and non-radiative recombination near interfaces are often considered responsible for the effect.

Carbon dot-wrapped perovskites could enable stable and efficient PSCs

Researchers from Australia's Queensland University of Technology (QUT) and Swinburne University of Technology have reported the creation of resilient, high-efficiency triple-cation perovskite solar cells (PSCs) by incorporating carbon dots (CDs) derived from human hair into the perovskite film.

QUT's Professor Hongxia Wang’s team had previously found that nanostructured carbon materials could be used to improve a cell’s performance. In their recent work, they tried using the carbon nanodots on perovskite solar cells. After adding a solution of carbon dots into the process perovskites synthesis, Professor Wang’s team found the carbon dots forming a wave-like layer where the perovskite crystals are surrounded by the carbon dots.

Researchers gain insights from close examination of the two-step deposition of perovskites in mesoporous-carbon-based perovskite solar cells

Researchers from The Hebrew University of Jerusalem and Ben-Gurion University of the Negev in Israel, have studied the two-step deposition of perovskites in mesoporous-carbon-based perovskite solar cells. The team studied the effect of the different deposition parameters on the PV performance and stability.

Schematic illustration of the two-step deposition process imageb) Schematic illustration of the two-step deposition process. The first stage includes dropping of the PbI2 þ PbBr2 solution, the second step includes dipping into the cation solution of FAI þ MABr. Image from article

The influence of the dipping time on the photovoltaic parameters was investigated using charge extraction and intensity-modulated photovoltage spectroscopy (IMVS) measurements. By modifying the perovskite precursors’ concentration and the dipping time, a PCE of 15% was achieved. The dipping time in the perovskite deposition of this solar cell structure is critical due to its thickness and mesoporous structure.

ORNL and University of Tennessee researchers design an automation process for choosing optimal perovskites to improve solar technologies

Researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL) and the University of Tennessee have proposed a way to automate the search for new materials, with a focus on metal halide perovskites (MHPs), to advance solar energy technologies. The study, part of an ORNL-UT Science Alliance collaboration, aims to identify the most stable MHP materials for device integration.

Automated chemistry sets new pace for materials discovery imageThe automated workflow combines chemical robotics and machine learning to speed the search for stable perovskites. Credit: Jaimee Janiga/ORNL, U.S. Dept of Energy

The team has developed a novel workflow that combines robotics and machine learning to study metal halide perovskites. “Our approach speeds exploration of perovskite materials, making it exponentially faster to synthesize and characterize many material compositions at once and identify areas of interest,” said ORNL’s Sergei Kalinin.

Unique method yields 23.2% efficient perovskite solar cells

Scientists from the University of North Carolina have developed a perovskite solar cell with an efficiency of 23.2% by adding benzylhydrazine hydrochloride (BHC) as an iodine (I) reductant agent in precursor solutions such as methylammonium iodide (MAI) and formamidinium iodide (FAI).

“Preventing the degradation of perovskite precursor solutions is equally important compared to post-fabrication device encapsulation, because large-area perovskite modules are generally manufactured in air and perovskite precursor inks are generally prepared in large quantity and stored for days or months,” the scientists said.