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Title :Computational Verification of So-Called Perovskite Solar Cells as PbI_6^<4−> -Aligned Solar Cells
Authors :Yanagida, Shozo
Yanagisawa, Susumu
Yanagida, Masatoshi
Segawa, Hiroshi
Issue Date :2017
Abstract :Effective sensitizing components in so-called perovskite solar cells (PSC) are lead hexaiodide (PbI_6^<4->) salts of PbI_6^<4-> (MeNH_3^+)n (n = 2∼4). Density-functional-theory-based molecular modeling (DFT/MM) of X-ray crystalline structure of PbI_6^<4->/MeNH_3^+ salt (FOLLIB) verifies that the packing unit of FOLLIB has UV/Vis absorption spectrum at λmax = 424 nm, giving pale yellow color as complementary color. DFT/MM of the horizontal component in the FOLLIB gives narrow energy gap of 0.3 eV, verifying remarkable semiconducting property through tight alignments of PbI_6^<4-> components coupled with MeNH_3^+. DFT/MM of the central PbI_6^<4->/MeNH_3^+ components verifies that the central component has UV/Vis absorption spectra with respective λmax = 570 nm, λmax = 762 nm and λmax = 945 nm, and plays an essential role as panchromatic sensitizers. In addition, their equilibrium geometric structures show slightly hypsochromic UV/Vis absorption spectra at respective λmax = 486 nm, λmax = 560 nm, and λmax = 563 nm as results of migration of MeNH_3^+ close to PbI_6^<4->. DFT/MM also verifies that PbI_6^<4-> components align tightly to nanocrystalline TiO_2 (nc-TiO_2) and to spiro-OMeTAD in PSC through electron density induced by van der Waals interaction. Electron density-based alignments of PbI_6^<4-> components well explain unidirectional and leakage-free electron diffusion leading to high open-circuit voltage in PbI_6^<4->-aligned solar cells. At the same time, the semiconducting and panchromatic sensitizing layer of PbI_6^<4->/MeNH_3^+ components contribute to excellent short-circuit photocurrent of PbI_6^<4->-aligned solar cells.
URL :http://dx.doi.org/10.1149/2.0341711jes
Type Local :雑誌掲載論文
ISSN :0013-4651
1945-7111
Publisher :The Electrochemical Society
URI :http://hdl.handle.net/20.500.12000/42932
Citation :Journal of The Electrochemical Society Vol.164 no.11 p.E3598 -E3605
Appears in Collections:Peer-reviewed Journal Articles (Faculty of Science)

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