69507-98-8Relevant articles and documents
Dynamic Optical Properties of CH3NH3PbI3 Single Crystals As Revealed by One- and Two-Photon Excited Photoluminescence Measurements
Yamada, Yasuhiro,Yamada, Takumi,Phuong, Le Quang,Maruyama, Naoki,Nishimura, Hidetaka,Wakamiya, Atsushi,Murata, Yasujiro,Kanemitsu, Yoshihiko
, p. 10456 - 10459 (2015)
The dynamic optical properties of perovskite CH3NH3PbI3 single crystals were studied by means of time-resolved photoluminescence (PL) spectroscopy at room temperature. The PL peak under one-photon excitation exhibits a red-shift with elapsing time, while two-photon PL is time-independent and appears at lower energy levels. The low-energy two-photon PL can be attributed to emissions from the localized states because of strong band-to-band absorption and photon re-absorption of the emitted light in the interior region. We revealed that the PL behaviors can be explained by the diffusion of photocarriers generated in the near-surface region to the interior region. The excitation fluence dependence of the one-photon PL dynamics is also discussed in terms of the electron-hole radiative recombination and carrier diffusion effects.
Colorimetric polarity chemosensor based on a organometal halide perovskite functional dye
Kim, Jong H.,Kim, Sung-Hoon
, p. 73 - 78 (2016)
We have investigated polarity sensing of organometal halide CH3NH3PbI3 perovskite functional dye based on hydrogen bonds between alcohols and polar units in perovskite. Upon exposure of alcohol solvents, perovskite film showed a drastic visible color change with different changing time depending on the polarities of alcohols. From the kinetic study of the reaction between perovskite dye and alcohols having different polarities, efficiency of hydrogen-bonding interactions between them were clearly revealed to be the main sensing mechanism, which enables effective discrimination of polarities by naked eyes. This study suggests a novel and practical sensing platform for highly sensitive colorimetric polarity chemosensors.
On the Demystification of “HPbI3” and the Peculiarities of the Non-innocent Solvents H2O and DMF
Daub, Michael,Hillebrecht, Harald
, p. 1393 - 1400 (2018)
Detailed investigations by XRD reveal that the precursor “HPbI3” that was obtained by reaction of aq. conc. hydroiodic acid HI and PbI2 in DMF is (CH3)2NH2PbI3. (CH3)2NH2+ is formed by solvent reaction as already described in the literature but not properly assigned. Attempts to synthesize HPbI3 by gas phase reaction of PbI2 with aq. conc. HI yielded light-yellow crystals of the oxonium salt H18O8Pb3I8 (Pbam, Z = 2, a = 10.075, b = 30.162, c = 4.5664 ?). The crystal structure of H18O8Pb3I8 consists of trimeric ribbons of edge-sharing PbI6 octahedra. These ribbons [Pb3I8]2– are separated by protonated fragments of crystalline ice [H18O8]2+ or (H2O)6(H3O+)2. H18O8Pb3I8 can also be precipitated from PbI2 and aq. conc. HI. H18O8Pb3I8 is not stable at room temperature but transforms within a few days to light-yellow (H3O)2x(H2O)2–2xPb1–xI2 with x ≈ 0.23 (R3m, Z = 3, a = 4.5554, c = 29.524 ?). The crystal structure represents a CdCl2-type layer structure with H2O/H3O+ in between. Charge compensation is achieved by Pb2+ vacancies. Via topotactic reaction (H3O)2x(H2O)2–2xPb1–xI2 releases H2O/HI and forms crystals of the pristine PbI2. All steps were characterized by P-XRD, IR/Raman spectra, and UV/Vis spectra. H18O8Pb3I8 acts as a precursor for the synthesis of MAPbI3 because the reaction with gaseous CH3NH2 yields MAPbI3, so it can mimic a composition “HPbI3”.
Random lasing in organo-lead halide perovskite microcrystal networks
Dhanker,Brigeman,Larsen,Stewart,Asbury,Giebink
, (2014)
We report optically pumped random lasing in planar methylammonium lead iodide perovskite microcrystal networks that form spontaneously from spin coating. Low thresholds (2) and narrow linewidths (Δλ 100 μm and spatially overlap with one another, resulting in chaotic pulse-to-pulse intensity fluctuations due to gain competition. These results demonstrate this class of hybrid organic-inorganic perovskite as a platform to study random lasing with well-defined, low-level disorder, and support the potential of these materials for use in semiconductor laser applications.
Cs/MAPbI3 composite formation and its influence on optical properties
Pawar, Vani,Kumar, Manish,Jha, Priyanka A.,Gupta,Jha, Pardeep K.,Singh, Prabhakar
, p. 935 - 942 (2019)
The stability issue is very critical for organic hybrid perovskite CH3NH3PbI3 to be used in solar cell applications; whereas CsPbI3 is reported to be more stable than that of CH3NH3PbI3. In the present work, we attempt to substitute Cs+ in the organic hybrid perovskite CH3NH3PbI3 matrix to form Csx(CH3NH3)1-xPbI3 with 0 ≤ x ≤ 0.4 in ambient conditions i.e., at room temperature and in air via solid state reaction route. The structural studies reveal presence of both CH3NH3PbI3 (tetragonal, I4/mcm) and CsPbI3 (orthorhombic, Pnma) phases for x > 0. It is appearing that partial solid solution formation has occurred up to x = 0.2 but for x > 0.2, the composite formation dominates. The optical band gap is slightly increased by ～0.02 eV with substitution. These compounds keep the basic feature of parent CH3NH3PbI3 along with stability of CsPbI3.
Loading of mesoporous titania films by CH3NH3PbI3 perovskite, single step vs. sequential deposition
Yantara, Natalia,Sabba, Dharani,Yanan, Fang,Kadro, Jeannette M.,Moehl, Thomas,Boix, Pablo P.,Mhaisalkar, Subodh,Gr?tzel, Michael,Gr?tzel, Carole
, p. 4603 - 4606 (2015)
Infiltration of mesoporous TiO2 scaffolds by CH3NH3PbI3 is more complete when using sequential compared to single step deposition processing and avoids formation of disordered capping layers affording greatly im
Orientation of organic cations in hybrid inorganic-organic perovskite CH3NH3PbI3 from subatomic resolution single crystal neutron diffraction structural studies
Ren, Yixin,Oswald, Iain W. H.,Wang, Xiaoping,McCandless, Gregory T.,Chan, Julia Y.
, p. 2945 - 2951 (2016)
We report the crystal growth of well-faceted single crystals of methylammonium lead iodide, CH3NH3PbI3, and detailed single crystal neutron diffraction structural studies aimed at elucidating the orientation of the methylammonium (CH3NH3+) cation in the tetragonal and cubic phases of the hybrid inorganic-organic perovskite. Room temperature experiments reveal a tetragonal structure where the protonated amine substituent (-NH3+) of the cation is disordered in four positions, each preferentially located near the neighboring iodine of the [PbI6] octahedra, while the methyl substituent (-CH3) is disordered in eight positions located near the body position of the unit cell. High temperature experiments show a cubic structure where the cation aligns along the [011] (edge), the [111] (diagonal), and the [100] (face) directions of the unit cell. The resulting site occupancy ratio suggests the CH3NH3+ cation resides primarily along the [011] direction, in agreement with reported DFT calculations. One important feature that was observed for both tetragonal and cubic structures measured at 295 and 350 K, respectively, is the middle point of the C-N bond being located off-center from the high symmetry sites in the crystal structure, induced by the formation of hydrogen bond-like interactions between the -NH3+ substituent of the organic cation and the iodine atoms of [PbI6] octahedra.
Ultra-high Seebeck coefficient and low thermal conductivity of a centimeter-sized perovskite single crystal acquired by a modified fast growth method
Ye, Tao,Wang, Xizu,Li, Xianqiang,Yan, Alex Qingyu,Ramakrishna, Seeram,Xu, Jianwei
, p. 1255 - 1260 (2017/02/10)
A centimeter-sized organic-inorganic hybrid lead-based perovskite CH3NH3PbI3 (MAPbI3) single crystal was obtained by using a modified fast and inverse-temperature growth method. The optical properties of this single crystal at room and low temperatures were studied in terms of optical absorption and photoluminescence measurements. The single crystal exhibited optical properties with a band-gap of 1.53 eV, which is comparable to a reported value. The temperature-dependent UV-vis spectra of this perovskite single crystal showed a unique structural phase transition as the temperatures varied. The thermoelectric properties of this MAPbI3 single crystal were studied, showing that the Seebeck coefficient of 920 ± 91 μV K?1 almost remained unchanged from room temperature to 330 K and it progressively increased with the increase in temperature and reached 1693 ± 146 μV K?1 at 351 K. In contrast, there was no very clear trend for thermal conductivities with changes in temperature. The thermal conductivities were maintained between 0.30 and 0.42 W m K?1 in the temperature range of 298-425 K. These thermoelectric characteristics would be useful for potential thermoelectric applications if the electrical conductivity of this crystal is improved by tuning its composition.
Effects of annealing temperature on stability of methylammonium lead iodide perovskite powders
Padchasri, Jintara,Yimnirun, Rattikorn
, p. 63 - 69 (2017/05/31)
The methylammonium lead iodide (CH3NH3PbI3 or MAPbI) material is currently investigated as active material in perovskite solar cells. Its stability, high optical band gap, low processing temperature and abundant elemental constituents provide numerous advantages over most powder absorber materials. In this work, the stability of MAPbI perovskite powders under different annealing temperature conditions was examined. X-ray diffraction (XRD) measurement demonstrated that the direct mixing synthesis method was able to produce a highly crystalline MAPbI material in a tetragonal phase structure. Thermal stability measurement based on the Simultaneous Thermal Analyzer (STA) indicated that the MAPbI was stable below 275 °C. The optical properties were characterized by employing refraction spectroscopy, which confirmed a direct bandgap of 1.53 eV in MAPbI perovskite powders. FT-Raman and XPS spectra confirmed the existence of organic groups. The annealing affected significantly the phase formation and stability of MAPbI. A small amount of lead iodide (PbI2), a product of the degradation, was observed with increasing annealing temperature. Therefore, a suitable annealing temperature should be chosen to produce MAPbI powders, which in turn will result in a high performance perovskite solar cell.
Towards toxicity removal in lead based perovskite solar cells by compositional gradient using manganese chloride
Singh, Pallavi,Rana, Prem Jyoti Singh,Dhingra, Pankul,Kar, Prasenjit
supporting information, p. 3101 - 3105 (2016/05/10)
We report synthetic steps towards a lead free manganese based perovskite MAPbxMn1-xI1+2xCl2-2x (nominal x = 0.1-1.0), photovoltaic material via a solid state reaction. Further application as an excellent panchromatic light harvester involves the fabrication of a cell with an inverted planar architecture at low processing temperature. This novel perovskite material offers an outstanding Voc of 1.19 V with fill factor of 87.9%.
