Metal halide perovskite photovoltaic cells could potentially boost the efficiency of commercial silicon modules from ∼20 toward 30% when used in tandem architectures. An optimum cell optical band gap ~1.75 electron volts (eV) can be achieved by varying composition, but to date, such materials have had poor photostability and thermal stability. Here we present a highly crystalline compositionally photostable material, [HC(NH2)2](0.83)Cs(0.17)Pb(I(0.6)Br(0.4))3, with an ~1.74 eV, fabricated...

Already exhibiting solar to electrical power conversion efficiencies of over 17%, organic–inorganic lead halide perovskite cells are one the most promising emerging contenders in drive provide a cheap and clean source energy. One concern however, is potential toxicology issue lead, key component archetypical material. The likely substitute tin, which like also group 14 metal. While tin perovskites have shown good semiconducting behaviour, instability its 2+ oxidation state has thus far...

The vast majority of perovskite solar cell research has focused on organic–inorganic lead trihalide perovskites; herein, we present working inorganic CsPbI₃perovskite cells for the first time.

Highest reported efficiency cesium lead halide perovskite solar cells are realized by tuning the bandgap and stabilizing black phase at lower temperatures. CsPbI2Br is employed in a planar architecture device resulting 9.8% power conversion over 5% stabilized output. Offering substantially enhanced thermal stability their organic based counterparts, these results show that all-inorganic perovskites can represent promising next step for photovoltaic materials. As service to our authors...

Lead-based halide perovskites are emerging as the most promising class of materials for next-generation optoelectronics; however, despite enormous success lead-halide perovskite solar cells, issues stability and toxicity yet to be resolved. Here we report on computational design experimental synthesis a new family Pb-free inorganic double based bismuth or antimony noble metals. Using first-principles calculations show that this hitherto unknown exhibits very optoelectronic properties, such...

A2BB′X6 halide double perovskites based on bismuth and silver have recently been proposed as potential environmentally friendly alternatives to lead-based hybrid perovskites. In particular, Cs2BiAgX6 (X = Cl, Br) synthesized found exhibit band gaps in the visible range. However, of these compounds are indirect, which is not ideal for applications thin film photovoltaics. Here, we propose a new class perovskites, where B3+ B+ cations In3+ Ag+, respectively. Our first-principles calculations...

Solution-processed metal halide perovskite semiconductors, such as CH3NH3PbI3, have exhibited remarkable performance in solar cells, despite having non-negligible density of defect states. A likely candidate is vacancies within the crystals, or presence metallic lead, both generated due to imbalanced I/Pb stoichiometry which could evolve during crystallization. Herein, we show that addition hypophosphorous acid (HPA) precursor solution can significantly improve film quality, electronically...

The recent discovery of lead-free halide double perovskites with band gaps in the visible represents an important step forward design environmentally friendly perovskite solar cells. Within this new family semiconductors, Cs2BiAgCl6 and Cs2BiAgBr6 are stable compounds crystallizing elpasolite structure. Following computational experimental synthesis these compounds, a detailed investigation their electronic properties is warranted order to establish potential as optoelectronic materials. In...

CsBr interface modification simultaneously enhances the device power conversion efficiency and improves resilience to UV irradiation.

Room-temperature films of black-phase cesium lead iodide (CsPbI3) are widely thought to be trapped in a cubic perovskite polymorph. Here, we challenge this assumption. We present structural refinement room-temperature CsPbI3 an orthorhombic demonstrate that polymorph is adopted by both powders and thin CsPbI3, fabricated either high- or low-temperature processes. perform electronic band structure calculations for the find agreement with experimental data close similarities methylammonium...

Hybrid metal-halide perovskites are promising new materials for use in solar cells; however, their chemical stability the presence of moisture remains a significant drawback. Quasi two-dimensional (2D) that incorporate hydrophobic organic interlayers offer improved resistance to degradation by moisture, currently still at cost overall cell efficiency. To elucidate factors affecting optoelectronic properties these materials, we have investigated charge transport and crystallographic...

The layered honeycomb magnet alpha-RuCl3 has been proposed as a candidate to realize Kitaev spin model with strongly frustrated, bond-dependent, anisotropic interactions between spin-orbit entangled jeff=1/2 Ru4+ magnetic moments. Here we report detailed study of the three-dimensional crystal structure using x-ray diffraction on untwinned crystals combined structural relaxation calculations. We consider several models for stacking layers and find evidence monoclinic unit cell corresponding...

Abstract In this work, the authors realize stable and highly efficient wide‐bandgap perovskite solar cells that promise high power conversion efficiencies (PCE) are likely to play a key role in next generation multi‐junction photovoltaics (PV). This work reports on (≈1.72 eV) exhibiting PCEs of up 19.4% remarkably open‐circuit voltage ( V OC ) 1.31 V. The ‐to‐bandgap ratio is highest reported for organic−inorganic hybrid also exceeds 90% theoretical maximum, defined by Shockley–Queisser...

A significant fraction of global electricity demand is for lighting. Enabled by the realization and development efficient GaN blue light-emitting diodes (LEDs), phosphor-based solid-state white LEDs provide a much higher efficiency alternative to incandescent fluorescent lighting, which are being broadly implemented. However, key challenge this industry achieve right photometric ranges application-specific emission spectra via cost-effective means. Here, we synthesize organic–inorganic lead...

Improvements in experimental resolution allow this group to elucidate how the electronic nematic transition evolves FeSe. They observe changing Fermi surface, position of lowest energy excitations, as well propensity towards order and its manifestation under strain.

Mixed-metal compositional screening identifies Co²⁺ as capable of partial B-site substitution in CH₃NH₃PbI₃, which supplies new dimensions material tunability.

Perovskite solar cells with record power conversion efficiency are fabricated by alloying both hybrid and fully inorganic compounds. While the basic electronic properties of perovskites now well understood, key parameters for cell performance, such as exciton binding energy perovskites, still unknown. By performing magneto-transmission measurements, we determine high accuracy reduced mass CsPbX3 (X = I, Br, an alloy these). The well-behaved (continuous) evolution band gap temperature in...

Abstract Optoelectronic devices based on hybrid halide perovskites have shown remarkable progress to high performance. However, despite their apparent success, there remain many open questions about intrinsic properties. Single crystals are often seen as the ideal platform for understanding limits of crystalline materials, and recent reports rapid, high-temperature crystallization single should enable a variety studies. Here we explore mechanism this find that it is due reversible changes in...

Lead halide perovskites are materials with excellent optoelectronic and photovoltaic properties. However, some hurdles remain prior to commercialization of these materials, such as chemical stability, phase sensitivity moisture, potential issues due the toxicity lead. Here, we report a new type lead-free perovskite related compound, Cs2PdBr6. This compound is solution processable, exhibits long-lived photoluminescence, an optical band gap 1.6 eV. Density functional theory calculations...

Recently, solution-processable organic-inorganic metal halide perovskites have come to the fore as a result of their high power-conversion efficiencies (PCE) in photovoltaics, exceeding 17%. To attain reproducibility performance, one critical factors is processing conditions perovskite film, which directly influences photophysical properties and hence device performance. Here we study effect annealing parameters on crystal structure films correlate these changes with its properties. We find...

Magnetoresistivity ρ(xx) and Hall resistivity ρ(xy) in ultrahigh magnetic fields up to 88 T are measured down 0.15 K clarify the multiband electronic structure high-quality single crystals of superconducting FeSe. At low temperatures high we observe quantum oscillations both effect, confirming Fermi surface with small volumes. We propose a novel approach identify from magnetotransport measurements sign charge carriers corresponding particular cyclotron orbit compensated metal. The observed...

Metal halide perovskites are promising candidates for use in light emitting diodes (LEDs), due to their potential color tunable and high luminescence efficiency. While recent advances perovskite-based have resulted external quantum efficiencies exceeding 12.4% the green emitters, infrared emitters based on 3 D/2D mixed dimensional exceeded 20%, of red blue still lag behind. A critical issue date is creating highly emissive stable perovskite with desirable emission band gap achieve full-color...

The presence of ${d}_{xz}\text{\ensuremath{-}}{d}_{yz}$ orbital ordering is often considered a hallmark the nematic phase Fe-based superconductors, including FeSe, but details order parameter remain controversial. Here, we report high-resolution angle-resolved photoemission spectroscopy study single crystals accounting for photon-energy dependence and making detailed analysis temperature dependence. We find that hole pocket undergoes fourfold-symmetry-breaking distortion in below 90 K, but,...

We report a high-resolution angle-resolved photo-emission spectroscopy study of the evolution electronic structure FeSe1-xSx single crystals. Isovalent S substitution onto Se site constitutes chemical pressure which subtly modifies FeSe at high temperatures and induces suppression tetragonal-symmetry-breaking structural transition temperature from 87K to 58K for x=0.15. With increasing substitution, we find smaller splitting between bands with dyz dxz orbital character weaker anisotropic...

During the past year, halide double perovskites attracted attention as potential lead-free alternatives to Pb-based perovskites. However, none of compounds discovered so far can match optoelectronic properties MAPbI3 (MA = CH3NH3). Here we argue that, from electronic structure viewpoint, only option make Pb-free retaining remarkable is combine In and Bi B+ B3+ cations, respectively. While inorganic such Cs2InBiX6 were found be unstable due In+ oxidizing into In3+, show that +1 oxidation...