Researchers develop artificial retinas with microcavity perovskite photoreceptors

Researchers at the National Tsing Hua University in Taiwan, led by Professor Hao-Wu Lin, have demonstrated that high-performance filter-less artificial human photoreceptors can be realized by integrating a novel optical metal/dielectric/metal microcavity structure with vacuum-deposited perovskite photoresponse devices.

Schematic and cross-sectional SEM image of the photoreceptor with an inverted structure image

Sensory substitution with flexible electronics is one of the intriguing fields of research. Scientists already fabricate electronic devices that can replicate, to a certain degree degree, some of the human senses – touch (electronic skin – e-skin), smell (e-nose), and taste (e-tongue). E-versions of the eye's photoreceptors (e-retinas) could potentially be used in a wide range of applications from robotic humanoid vision to artificial retina implantation for vision restoration or even vision extension into a wider range of wavelength.

HZB team opens the door to stable PSCs based on inorganic perovskite thin films

A team at the Helmholtz-Zentrum Berlin (HZB) has succeeded in producing inorganic perovskite thin films at moderate temperatures using co-evaporation – rendering the process of post-tempering at high temperatures unnecessary it much easier to produce thin-film solar cells.

HZB team opens the door to stable PSCs based on inorganic perovskite thin films imageBy co-evaporation of cesium iodide and lead iodide thin layers of CsPbI3 can be produced even at moderate temperatures. An excess of cesium leads to stable perovskite phases. image: HZB

Researchers all over the world are working intensively on the development of perovskite solar cells. The focus is mainly on ones made from metal-organic hybrid perovskites, whose crystal structure is composed of inorganic elements such as lead and iodine as well as an organic molecule. Completely inorganic perovskite semiconductors such as CsPbI3 have the same crystalline structure as hybrid perovskites, but contain an alkali metal such as caesium instead of an organic molecule. This makes them much more stable than hybrid perovskites, but usually requires an extra production step at very high temperature – several hundred degrees Celsius.

Caffeine can make perovskite solar cells more stable under heat

Researchers at the California NanoSystems Institute at UCLA have discovered that caffeine improves the thermal stability of perovskite solar cells.

“Solar cells need high thermal stability since they are constantly exposed to sunlight, which warms up the devices,” said Yang, who is also a professor of materials science and engineering at the UCLA Samueli School of Engineering. “While perovskites are an attractive option for solar cells, the materials degrade and become less stable over time. We need them to last 20 to 30 years like traditional solar cells.”

NREL team boost PSC efficiency using a new chemical formula

Researchers at the National Renewable Energy Laboratory (NREL) report the creation of an efficient tandem perovskite solar cell, using a new chemical formula which also improved the structural and optoelectronic properties of the solar cell.

Most of the research efforts in the field of PSCs have focused on lead-based perovskites, which have a wide bandgap. High efficiency, low bandgap perovskites would enable the fabrication of very high efficiency all-perovskite tandem solar cells where each layer absorbs only a part of the solar spectrum and is optimally configured to convert this light into electrical energy. However, low bandgap perovskites have long suffered from large energy losses and instability limiting their use in tandems.

Taiwanese researchers develop perovskite solar cells that convert indoor light to power

Researchers from the Research Center for New Generation Photovoltaics (RCNPV) in Taiwan have developed solid-state perovskite solar cells which can convert indoor light to power IoT sensors.

Research Center for New Generation Photovoltaics (RCNPV) director, Wu Chun-guey, said: "Power conversion for a perovskite solar cell with area of 0.0739 square cm is 23.7%, and the efficiency decreases to 20.9% for cell area of one square cm, 17.25% for 17.277 square cm, and 11.7% for 703 square cm".

Researchers improved the stability of PSCs using hybrids of graphene and molybdenum disulphide quantum dots

Researchers from the Graphene Flagship have managed to increase the stability of perovskite solar cells (PSCs) using hybrids of graphene and molybdenum disulphide quantum dots.

Graphene inks help stabilize the stability of perovskite solar cells

The team used molybdenum disulphide quantum dot/graphene hybrids to address PSCs' instability issue. The collaboration between research institutions and industrial partners enabled by Graphene Flagship, yielded an ink based on graphene and related materials (GRMs). Layering this over the PSCs caused them to drastically increase in stability.

Researchers develop novel flexible perovskite solar cells for potential use in wearables

A joint research team including scientists from the Chinese Academy of Scinces (CAS), Shijiazhuang Tiedao University in China and Chiao Tung University in Taiwan has developed a novel type of highly flexible and stable perovskite-based solar cell that could be used in wearable electronics.

The team stated that current PSCs are mainly made of a polymer substrate, which has been proven fragile, unstable and not adequately waterproof. The team built a new type of PSC based on an inorganic mica substrate, which could reduce the strain in the device even under large bending deformation. Mica is a mineral that separates easily into small flat transparent pieces of rock.