Perovskite materials - Page 13

New process yields oxide perovskite crystals in flexible, free-standing layers

Researchers at the University of California, Irvine and other institutions have developed a new process for producing oxide perovskite crystals in flexible, free-standing layers.

'Through our successful fabrication of ultrathin perovskite oxides down to the monolayer limit, we've created a new class of two-dimensional materials,' said co-author Xiaoqing Pan, professor of materials science & engineering at UCI. 'Since these crystals have strongly correlated effects, we anticipate they will exhibit qualities similar to graphene that will be foundational to next-generation energy and information technologies.'

Read the full story Posted: Jun 17,2019

Researchers demonstrate high light extraction efficiency of perovskite photonic crystals

Researchers at NTU, lead by Assoc. Prof. Wang Hong, recently demonstrated high light extraction efficiency of perovskite photonic crystals fabricated by delicate electron-beam lithography.

Researchers demonstrate high light extraction efficiency of perovskite photonic crystals image

The perovskite photonic crystals exhibit both emission rate inhibition and light energy redistribution simultaneously. They observed 7.9-fold reduction of spontaneous emission rate with a slower decay in perovskite photonic crystals due to photonic bandgap effect (PBG).

Read the full story Posted: Apr 01,2019

The Perovskite Handbook

Perovskite-Info is proud to present The Perovskite Handbook. This book is a comprehensive guide to perovskite materials, applications and industry. Perovskites are materials that share a similar structure, which display a myriad of exciting properties and are considered the future of solar cells, displays, sensors, lasers and more.

The Perovskite Handbook

Reading this book, you'll learn all about:

  • Different perovskite materials, their properties and structure
  • How perovskites can be made, tuned and used
  • What kinds of applications perovskites may be suitable for
  • What the obstacles on the way to a perovskite revolution are
  • Perovskite solar cells, their merits and challenges
  • The state of the perovskite market, potential and future

Read the full story Posted: Nov 27,2018

Researchers develop a cryogenic process for PSC production without anti-solvents

Researchers from Nazarbayev University in Kazakhstan and Hong Kong Polytechnic University have demonstrated a new 4-step process including (i) spin-coating of the precursors; (ii) cryogenic treatment; (iii) blow-dry process for the removal of the solvent; and (iv) thermal annealing. This process is a straightforward and effective technique which can yield homogenous perovskite films without the use of anti-solvents and regardless of the complexity of the precursor compositions.

Researchers develop a cryogenic process for PSC production without anti-solvents image

When mixed perovskite precursor solutions are evaporated, usually non-uniform films with poor morphology are obtained due to coalescence of perovskite crystallites during rapid solvent removal. Therefore, anti-solvents are usually used to preapare mixed perovskite thin films. However, this technique is not convenient for large-scale manufacturing in industry since the final perovskite film quality critically depends on multiple parameters while adding the anti-solvent. Inaccurate control of the mixing process will cause gradients in over-saturation of the precursor solution, leading to spatially inhomogeneous nucleation of the perovskite and deterioration of the resultant film quality. Furthermore, commonly used anti-solvents such as chlorobenzene or toluene are environmentally harmful and highly toxic. The team's new method circumvents these issues and offers an improved alternative that enhances the control over the perovskite growth process, decoupling the nucleation and crystallization phases.

Read the full story Posted: Oct 03,2018

Penn State team gains new insight into how halide perovskite materials enable the efficient conversion of sunlight into electricity

Researchers at Penn State have gained new insight into how halide perovskite materials enable the efficient conversion of sunlight into electricity.

Penn State team gains new insight into how halide perovskite materials enable the efficient conversion of sunlight into electricity image

Scientists state that halide perovskites tend to have a unique tolerance for imperfections in their structures, which allows them to efficiently convert sunlight into electricity when other materials with similar imperfections do not. What makes these materials so tolerant of imperfections, however, was unknown prior to this study. The researchers used ultrafast infrared imaging technology to investigate how the structure and composition of these materials influence their ability to convert sunlight into electricity.

Read the full story Posted: Oct 02,2018

Researchers define the perovskite ‘humidity loop’

Researchers at the University of Maryland (UMD) have identified the impact of the environment on perovskite materials. To understand the physical and chemical processes that lead to degradation, the team exposed these materials to various environmental factors in the lab and measured their response using a technique called 'in situ environmental photoluminescence (PL) to temporally and spectrally resolve the light emission within a loop of critical relative humidity (rH) levels.'

Perovskite humidity loop image

'We found that the humidity pathway determines the overall optical response of the perovskite materials, leading to a behavior called luminescence hysteresis, wherein the light emitted from the material depends not only on the current conditions but also the prior ones,' said the team. 'Further, we found that the amount of luminescence hysteresis is highly dependent on the ratio between two critical elements constituting the perovskites: Cs and Br.'

Read the full story Posted: Jun 28,2018

Avantama demonstrates its perovskite QDs at SID Displayweek 2018

Switzerland-based Avantama demonstrated its perovskite quantum dots at Displayweek 2018. QDs are currently used as color down-conversion films to turn the emission of blue LEDs to white light.

Currently used QDs are either Cadmium-based or Indium-based, and Avantama claims that its pQDs outperform both technologies by a wide margin (3X CdSe, 12x InP), which means that using these will enable much more efficient QD-LCDs. Of course pQDs contain lead, but the amount is very small and it is way below the thresholds required by the EU and other countries.

Read the full story Posted: Jun 04,2018

Oxford University team sets out to predict future perovskites

Oxford University researchers attempted to understand what makes certain combinations of elements in the Periodic Table arrange as perovskite crystals and others not, and whether the number and nature of undiscovered pervoskites can be.

The team examined the Norwegian mineralogist Victor Goldschmidt's 1926 hypothesis known as the 'no-rattling' approach: that the formability of perovskites follows a simple geometric principle, namely: The number of anions surrounding a cation tends to be as large as possible, subject to the condition that all anions touch the cation. It basically means that if we describe a crystal using a model of rigid spheres, in a perovskite the spheres tend to be tightly packed, so that none can move around freely. Using elementary geometry, Goldschmidt's hypothesis can be translated into a set of six simple mathematical rules that must be obeyed by the ions of a perovskite.

Read the full story Posted: May 13,2018

Chinese scientists synthesize lead-free double perovskite nanocrystals

A research team at the Dalian Institute of Chemical Physics (DICP) in the Chinese Academy of Sciences synthesized a new lead-free double perovskite nanocrystals (NCs) and revealed the hot-carrier dynamic of it.

Chinese team develops lead-free perovskite nanocrystals image

To avoid the toxicity issue of Pb, many efforts of finding a possible replacement are made. "We prepared the lead-free 3D double perovskite NCs and demonstrated that the continuously tunable emission ranged from 395 to 575 nm," said the researchers

Read the full story Posted: Mar 29,2018

Cornell team uses laser pulses to change the properties of a perovskite material

Researchers at Cornell used theoretical techniques to predict that using intense mid-infrared laser light on a titanium perovskite can dynamically induce a magnetic phase transition ' taking the material from its ferromagnetic ground state to a hidden anti-ferromagnetic phase. This dramatic shift could have useful applications, particularly in optical information processing.

'It would be a kind of optical switch,' the researchers said. 'You have a material where it's magnetic and 'non-magnetic.' It's going between those two states with light'.

Read the full story Posted: Mar 13,2018