The vapors in equilibrium with condensates of DyI3, DyI3/InI, TmI3, and TmI3/TlI were observed over the temperature range from 900 K to 1400 K using x-ray induced fluorescence. The total densities of each element (Dy, Tm, In, Tl, and I) in the vapor, summed over all atomic and molecular species, were determined. Dramatic enhancements in the total vapor densities of Dy and Tm were observed in the vapors over DyI3/InI and TmI3/TlI as compared to the vapors over pure DyI3 and pure TmI3, respectively. An enhancement factor exceeding 10 was observed for Dy at T ≈ 1020 K, decreasing to 0 at T ≈ 1250 K. An enhancement factor exceeding 20 was observed for Tm at T ≈ 1040 K, decreasing to 0 at T ≈ 1300 K. Such enhancements are expected from the formation of the vapor-phase hetero-complexes DyInI4 and TmTlI4. Numerical simulations of the thermo-chemical equilibrium suggest the importance of additional complexes in liquid phases. A description of the measurement technique is given. Improvements in the absolute calibration lead to an approximately 40% correction to previously reported preliminary results [J. J. Curry et al., Chem. Phys. Lett. 507, 52 (2011); Appl. Phys. Lett. 100, 083505 (2012)].
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http://dx.doi.org/10.1063/1.4821828 | DOI Listing |
ACS Appl Mater Interfaces
September 2020
Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
Although rapid progress has been made in tin-based perovskite solar cells (PSCs), the inferior film qualities of the solution-processed perovskites always lead to poor reproducibility and instability. Herein, we present a simple seeded growth (SG) approach to obtain high-quality tin-based perovskite films with preferred crystal orientation, large grain sizes, and fewer apparent grain boundaries. High-quality tin-based perovskite films fabricated through this SG process could greatly reduce the nonradiative recombination centers and inhibit the oxidation of Sn.
View Article and Find Full Text PDFACS Appl Mater Interfaces
March 2020
Key Laboratory of Novel Thin-Film Solar Cells, North China Electric Power University, Beijing 102206, P. R. China.
Recently, mixed-cation perovskites have been extensively used for high-performance solar cells. Nevertheless, the mixed-cation perovskite based on formamidinium methylammonium lead tri-iodide (FAMAPbI) fabricated through the existing methods often suffers from phase stability and trap density. Herein, we demonstrate a facile intermediate engineering approach to improve the quality of the mixed-cation perovskite based on FAMAPbI.
View Article and Find Full Text PDFNanoscale
March 2019
Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
Perovskites with mixed organic cations possess better properties in some aspects as compared to their pure counterparts. However, the structural and optical properties of these mixed-type perovskites have been rarely investigated. In this study, probable structures of mixed organic cation perovskites, MAxFA1-xPbI3 (x = 1, 0.
View Article and Find Full Text PDFNanoscale
March 2017
University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
The family of organic-inorganic tri-halide perovskites including MA (MethylAmmonium)PbI, MAPbICl, FA (FormAmidinium)PbI and FAPbBr are having a tremendous impact on the field of photovoltaic cells due to the combination of their ease of deposition and high energy conversion efficiencies. Device performance, however, is known to be still significantly affected by the presence of inhomogeneities. Here we report on a study of temperature dependent micro-photoluminescence which shows a strong spatial inhomogeneity related to the presence of microcrystalline grains, which can be both bright and dark.
View Article and Find Full Text PDFNano Lett
September 2016
Global Frontier Center for Multiscale Energy Systems, Seoul 151-742, Republic of Korea.
Enhancing hole extraction inside the perovskite layer is the key factor for boosting photovoltaic performance. Realization of halide concentration gradient perovskite materials has been expected to exhibit rapid hole extraction due to the precise bandgap tuning. Moreover, a formation of Br-rich region on the tri-iodide perovskite layer is expected to enhance moisture stability without a loss of current density.
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