Search results for "PEROVSKITE"

Vapor-Deposited Perovskites: The Route to High-Performance Solar Cell Production?

2017

Summary High-quality semiconducting perovskites can be easily synthesized through several methods. The ease of fabrication has favored the adoption of lab-scale solution-processing techniques, which have yielded the highest performing devices. Most of these processes, however, are not directly applicable to larger scale and volume preparations, hindering the consolidation and market entry of this technology. Vapor-based methods, a mature technology widely adopted in the coating and semiconductor industry, could change this trend. Their application to perovskite solar cells includes a large amount of fabrication approaches, offering versatility in the employed materials as well as in the cha…

Optical Amplification in Hollow-Core Negative-Curvature Fibers Doped with Perovskite CsPbBr3 Nanocrystals

2019

| openaire: EC/H2020/820423/EU//S2QUIP We report a hollow-core negative-curvature fiber (HC-NCF) optical signal amplifier fabricated by the filling of the air microchannels of the fiber with all-inorganic CsPbBr3 perovskite nanocrystals (PNCs). The optimum fabrication conditions were found to enhance the optical gain, up to +3 dB in the best device. Experimental results were approximately reproduced by a gain assisted mechanism based on the nonlinear optical properties of the PNCs, indicating that signal regeneration can be achieved under low pump powers, much below the threshold of stimulated emission. The results can pave the road of new functionalities of the HC-NCF with PNCs, such as op…

The electronic properties of SrTiO3-δ with oxygen vacancies or substitutions

2021

The authors would like to thank R. Dittmann for useful discussions, T. Kocourek, O. Pacherova, S. Cichon, V. Vetokhina, and P. Babor for their contributions to sample preparation and characterization. The authors (M.T., A.D.) acknowledge support from the Czech Science Foundation (Grant No. 19-09671S), the European Structural and Investment Funds and the Ministry of Education, Youth and Sports of the Czech Republic through Programme “Research, Development and Education” (Project No. SOLID21 CZ.02.1.01/0.0/0.0/16-019/0000760). This study was partly supported by FLAG-ERA JTC project To2Dox (L.R. and E.K.). Calculations have been performed on the LASC Cluster in the Institute of Solid State Phy…

Effects of Mn doping on dielectric properties of ferroelectric relaxor PLZT ceramics

2017

This work has been supported by Latvian state research program IMIS2 .

Ab initio simulation of (Ba,Sr)TiO3 and (Ba,Ca)TiO3 perovskite solid solutions

2019

This research was supported by the ERA-NET HarvEnPiez project. Many thanks to R. Dovesi, M.M. Kržmanc and D. Gryaznov for fruitful discussions.

Improving Long Term Stability of Pure Formamidinium Perovskite Solar Cells by Ambient Air Additive Assisted Fabrication

2021

Quantum chemical modelling of electron polarons and  green  luminescence in PbTiO3perovskite crystals

2002

In an extension of our previous study on the electron polarons and excitons in KNbO3, KTaO3 and BaTiO3 (Kotomin E A, Eglitis R I and Borstel G 2000 J. Phys. Condens. Matter 12 L557; Eglitis R I, Kotomin E A and Borstel G 2002 J. Phys. Condens. Matter 14 3735) by the semiempirical Hartree–Fock method we present here results for free electron polarons in the PbTiO3 perovskite crystal. We discuss the origin of the intrinsic visible band emission of PbTiO3 perovskite oxides (so-called 'green luminescence') which has remained a topic of high interest during the last quarter of a century. We present a theoretical calculation modelling this emission in the framework of a concept of charge transfer…

Online Meetings in Times of Global Crisis: Toward Sustainable Conferencing

2020

International conferences are an essential component of the timely exchange of ideas and results in the scientific community, where scientists present their results, gain new insights, and meet colleagues and collaborators. In early 2020, a global pandemic caused by a coronavirus (SARS-CoV-2) and the corresponding disease (covid-19) resulted in a number of conferences being canceled or postponed. (1) To foster scientific exchange despite the restrictions, a range of initiatives were launched across the globe to move international conferences online. (2−8) [...]

Interface engineering in efficient vacuum deposited perovskite solar cells

2016

Abstract We studied the effect of the charge transport layers in p-i-n perovskite solar cells using vacuum deposited methylammonium lead iodide thin-film absorbers. While solution-processed perovskite films are frequently deposited directly on PEDOT:PSS leading to good solar cell performances, in some cases even to very good Voc values, we show that in devices employing vacuum deposited MAPbI3 perovskites, the removal of the polyTPD electron blocker substantially reduces the photovoltaic behavior. This is indicative of rather different charge transport properties in the vacuum deposited MAPbI3 perovskites compared to those prepared from solution. On the other hand, we investigated the use o…

Quantum chemical modelling of polarons and perovskite solid solutions

2001

Abstract Following our previous study [J. Phys.: Condens. Matter 10 (1998) 6271] of a single Nb impurity and Nb clusters in KTaO 3 , we present results of the calculations for a series of perovskite KNb x Ta 1− x O 3 (KTN) solid solutions ( x =0, 0.125, 0.25, 0.75, 1). The quantum chemical method of the intermediate neglect of the differential overlap (INDO) combined with the large unit cell (LUC) periodic model is used. According to the INDO calculations, Nb impurity becomes off-center in KTaO 3 already at the lowest studied concentrations ( x =0.125), in a good agreement with XAFS measurements. We compare our results with previous ab initio FP-LMTO calculations. Quantum chemical calculati…