Technical / research - Page 31

Researchers from the University of Cambridge have designed a reactor that is able to convert CO₂, water, and plastics into syngas. The system is based on a photoelectrochemical (PEC) device powered by an encapsulated triple cation perovskite-based photocathode and an alloy anode.

The PEC system initially captures CO₂ from a concentrated CO₂ stream, simulated post-combustion flue gas, and atmospheric air. It then converts this CO₂ into syngas, a mixture of carbon monoxide (CO), and hydrogen (H₂).

Researchers from Saudi Arabia's King Abdullah University of Science and Technology (KAUST) have conducted a series of tests to see if the temperature coefficient of the short circuit current in perovskite-silicon tandem solar cells could be a proper standard of measurement to analyze their behavior and performance. The team has come to the conclusion that it may not be considered a proper metric to assess these devices’ performance and behavior.

The scientists explained that the idea of their recent paper was to show that the temperature coefficient of the short circuit current, measured under standard illumination conditions, might not well describe the actual operation of tandem solar cells. Depending on the local spectrum and the temperature range, the current at maximum power (Impp) can increase, decrease or have a mixed behavior. This intriguing effect can help the community to better understand their outdoor data as outdoor tandem operation should become more and more common in the next years.

An international team has designed a perovskite solar cell with an electron transport layer (ETL) made of indium sulfide (In₂S₃) that could reportedly reduce the defect density in the device.

The scientists used a numerical module and the SCAPS-1D solar cell capacitance software, which is a simulation tool for thin-film solar cells that was developed by the University of Ghent in Belgium, to simulate s solar cell based on methylammonium lead iodide (MAPbI₃).

Researchers from the Chinese Academy of Sciences (CAS) have used graphdiyne oxide (GDYO), fluorinated GDYO (FGDYO) and nitrogen-doped GDYO (NGDYO) to improve the SnO₂ electron transport layer (ETL) in perovskite solar cells and revealed the relevant mechanism using synchrotron radiation technology. 

The team tracked the growth process of SnO₂, PbI₂ and perovskite using in situ XRD and the chemical bonds on the interface between ETL and the active layer using in situ XAFS. They found that the stronger interaction between the doped SnO₂ and PbI₂ inhibited PbI₂ crystallization in perovskite layers and gave more opportunity for the PbI₂ precursor to form perovskite, thus making perovskite crystallize better.

Researchers from Ames National Laboratory worked with scientists at the Swiss Federal Institute of Technology in Zürich (ETH Zurich) to understand how to assemble perovskites (that are shaped as nanocubes) with other sphere-shaped nanocrystals. 

The scientists used the Expanse supercomputer at the San Diego Supercomputer Center (SDSC) at UC San Diego to identity the general rules that enable the assembly of nanocubes like perovskites with spherical nanoparticles. Ultimately, they conducted a study to assist with the design of future nanoparticle-based materials. Their recent paper provides details on both their results and problems when pairing the perovskites with spherical nanocrystals.

Researchers from Purdue University, University of California and the University of Kentucky have constructed a new perovskite interlayer that reportedly exhibits both superior thermal and moisture stability in ambient conditions.

“Enhancing the stability and lifetime of perovskite devices is necessary in order to realize the goal of commercialization for perovskite photovoltaics,” said Jiaonan Sun. “Today, the stability of commonly used hole transporting layers (HTL) is still a bottleneck for achieving the required lifetime". Poly(triaryl amine) (PTAA) is a promising polymeric hole transporting material used in PSC applications, however, it’s hydrophobicity causes problematic interfacial contact with perovskite, limiting the device’s performance. Led by Dr. Letian Dou, the researchers successfully constructed a uniform two-dimensional (2D) perovskite interlayer with conjugated ligands, between three-dimensional (3D) perovskites and PTAA to improve the power conversion efficiency and the interfacial adhesion of the devices. These increased-ion migration, energy barrier conformal, 2D coated unencapsulated devices with new ligands provide greater thermal and moisture stability in different environments.

Researchers from CNR-IMM,CNR-IPCB, CNR-NANOTEC, Università Degli Studi di Messina and the University of Basel have shown that lead leakage can be prevented by applying a transparent titanium dioxide (TiO₂) sponge in a semitransparent solar cell. The device has demonstrated comparable efficiency to semi-transparent perovskite devices and has an average visible transmittance (AVT) of 31.4%.

The team designed the solar cell for applications such as building-integrated photovoltaics (BIPV) and agrivoltaics, in which the potential lead leakage can be seen as a serious public environmental and health risk source. 

Researchers from Nanjing Tech University, Wuhan University of Technology and National University of Singapore set out to address two major issues that should be resolved in order to promote perovskite solar cells (PSCs): disorder crystallization of perovskite and unbalanced interface charge extraction, which limit further improvements in device efficiency. 

The team used a thermally polymerized additive N-vinyl-2-pyrrolidone (NVP) as a polymer template in the perovskite film, followed by a conventional HTL/Chlorobenzene (CB) solution spin-coating process to remove the residual miscellaneous phases and open the grain boundaries to form monolithic perovskite grains, thereby suppressing the defect-related non-radiative recombination. Furthermore, this process results in the formation of a novel “Mortise-Tenon” (M-T) structure for perovskite/HTL composite film, which provides a larger contact area between perovskite and HTL, thereby facilitating hole extraction to achieve balanced charge management. 

An international team of scientists from Fritz Haber Institute of the Max Planck Society, École Polytechnique in Paris, Columbia University in New York, and the Free University in Berlin have demonstrated laser-driven control of fundamental motions of the lead halide perovskite (LHP) atomic lattice.

Sketch of the experimental pump-probe configuration. Image from Science Advances

By applying a sudden electric field spike faster than a trillionth of a second (picosecond) in the form of a single light cycle of far-infrared Terahertz radiation, the team unveiled the ultrafast lattice response, which might contribute to a dynamic protection mechanism for electric charges. This precise control over the atomic twist motions could allow to create novel non-equilibrium material properties, potentially providing hints for designing the solar cell material of the future.

Researchers from Xiamen University and China Jiliang University have reported ultrahigh-efficiency green PeLEDs with quantum efficiencies surpassing a milestone of 30% by regulating the charge carrier transport and near-field light distribution to reduce electron leakage and achieve a high light outcoupling efficiency of 41.82%. 

The scientists applies Ni_0.9Mg_0.1O_x films with a high refractive index and increased hole carrier mobility as the hole injection layer to balance the charge carrier injection and insert the polyethylene glycol layer between the hole transport layer and the perovskite emissive layer to block the electron leakage and reduce the photon loss.