@article{Morais2024b,

title = {Unraveling Interfacial Photoinduced Charge Transfer and Localization in CsPbBr3 Nanocrystals/Naphthalenediimide},

author = {Eliane A. Morais and Maykon A. Lemes and Natalilian R. S. Souza and Amando Siuiti Ito and Evandro L. Duarte and Ronaldo S. Silva and Sergio Brochsztain and J. A. Souza},

url = {https://pubs.acs.org/doi/10.1021/acsomega.4c01651},

doi = {10.1021/acsomega.4c01651},

issn = {2470-1343},

year  = {2024},

date = {2024-05-09},

urldate = {2024-05-09},

journal = {ACS Omega},

publisher = {American Chemical Society (ACS)},

abstract = {Halide perovskites have attracted much attention for energy conversion. However, efficient charge carrier generation, separation, and mobility remain the most important issues limiting the higher efficiency of solar cells. An efficient interfacial charge transfer process associated with exciton dynamics between all-inorganic CsPbBr3 nanocrystals and organic electron acceptors has been suggested. We observed a strong PL quenching of 78% in thin films when silane-functionalized naphthalenediimides (SNDI), used as electron-acceptors, are anchored on CsPbBr3 nanocrystals. Optical and structural characterizations confirm the charge transfer process without QDs degradation. The issue of whether these transferred charges are indeed available for utilization in solar cells remains uncertain. Our results reveal that the CsPbBr3 nanocrystals capped with these electron-acceptor SNDI molecules show a drastic increase in the electrical resistance and the absence of a photoconductivity effect. The results suggest charge transfer followed by strong localization of the charge carriers, preventing their extraction toward the electrodes of solar cell devices. We hope that this crucial aspect to attract attention and unveil a potential mechanism for charge delocalization, which could, in turn, lead to a groundbreaking enhancement in solar cell efficiency.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Morais2024c,

title = {Rashba Spin Splitting Limiting the Application of 2D Halide Perovskites for UV-Emitting Devices},

author = {Eliane A. Morais and Naidel A. M. S. Caturello and Maykon A. Lemes and Henrique Ferreira and Fabio F. Ferreira and Jose J. S. Acuña and Sergio Brochsztain and Gustavo M. Dalpian and J. A. Souza},

url = {https://pubs.acs.org/doi/abs/10.1021/acsami.3c16541},

doi = {10.1021/acsami.3c16541},

issn = {1944-8252},

year  = {2024},

date = {2024-01-24},

urldate = {2024-01-24},

journal = {ACS Appl. Mater. Interfaces},

volume = {16},

number = {3},

pages = {4261--4270},

publisher = {American Chemical Society (ACS)},

abstract = {Layered lead halide perovskites have attracted much attention as promising materials for a new generation of optoelectronic devices. To make progress in applications, a full understanding of the basic properties is essential. Here, we study 2D-layered (BA)2PbX4 by using different halide anions (X = I, Br, and Cl) along with quantum confinement. The obtained cell parameter evolution, supported by experimental measurements and theoretical calculations, indicates strong lattice distortions of the metal halide octahedra, breaking the local inversion symmetry in (BA)2PbCl4, which strongly correlates with a pronounced Rashba spin-splitting effect. Optical measurements reveal strong photoluminescence quenching and a drastic reduction in the PL quantum yield in this larger band gap compound. We suggest that these optical results are closely related to the appearance of the Rashba effect due to the existence of a local electric dipole. The results obtained in ab initio calculations showed that the (BA)2PbCl4 possesses electrical polarization of 0.13 μC/cm2 and spin-splitting energy of about 40 meV. Our work establishes that local octahedra distortions induce Rashba spin splitting, which explains why obtaining UV-emitting materials with high PLQY is a big challenge.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Freitas2023,

title = {Water-induced dimensionality conversion from 3D perovskites to microwires and 2D hybrid halide perovskites},

author = {Andre L. M. Freitas and J. A. Souza},

url = {https://pubs.rsc.org/en/content/articlelanding/2023/tc/d3tc00593c/unauth},

doi = {10.1039/d3tc00593c},

issn = {2050-7534},

year  = {2023},

date = {2023-05-25},

urldate = {2023-05-25},

journal = {J. Mater. Chem. C},

volume = {11},

number = {20},

pages = {6651--6661},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {Important applications of hybrid organic–inorganic halide perovskites are closely related to their crystal organization leading to different electronic structures. Adapting the dimensionality in lead halide perovskites along with inherent quantum confinement effects in the building blocks of n layers of [MX6]4− octahedral sheets can further influence the optoelectronic properties. The [MX6]4− octahedral array defining the dimensionality is crucial for stability, exciton dynamics, bandgap energy, and charge transport. Here, we demonstrate the water-assisted formation of both microwires and 2D layered morphologies from 3D MAPbBr3 microcubes through a dissociation–recrystallization process. Besides the systematic changes in the bandgap energy, our study reveals an effect on trap- and excito-assisted recombination life-times due to the changes in exciton binding energy along with a dependence on the structural confinement. We show the role and the importance of controlling the water and organic molecules in a precursor ionic solution which can induce and/or inhibit the growth confining the charge in one or two directions, leading to a change in the optical properties and exciton dynamics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bonadio2023,

title = {Comparing the Cubic and Tetragonal Phases of MAPbI3 at Room Temperature},

author = {Ariany Bonadio and Fernando P. Sabino and André L. M. Freitas and Marissol R. Felez and Gustavo M. Dalpian and J. A. Souza},

url = {https://pubs.acs.org/doi/abs/10.1021/acs.inorgchem.3c00874},

doi = {10.1021/acs.inorgchem.3c00874},

issn = {1520-510X},

year  = {2023},

date = {2023-05-15},

urldate = {2023-05-15},

journal = {Inorg. Chem.},

volume = {62},

number = {19},

pages = {7533--7544},

publisher = {American Chemical Society (ACS)},

abstract = {Stability and maintenance of the crystal structure are the main drawbacks of the application of organic–inorganic perovskites in photovoltaic devices. The ΔT = 62 K robust shift of the structural phase transition observed here allows us to conduct a comprehensive study at room temperature of the tetragonal versus cubic phase on MAPbI3. The absence of the shift in the cubic transition for all-inorganic CsPbI3 samples confirms the importance of both orientation and dynamics of the organic cations. Our results provide a unique opportunity to evaluate the physical properties of both cubic and tetragonal phases of MAPbI3 at the same temperature, eliminating different phonon effects as possible causes for different properties. Besides higher electrical resistivity, the perovskite cubic phase presents a faster charge carrier lifetime than the tetragonal phase and partial PL quenching, pointing toward increased trap-assisted nonradiative recombination. The light absorption coefficient in the cubic phase is larger than the absorption in the tetragonal phase in the green region.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{MartinsFreitas2023,

title = {Finite-Size Effects on Cs3Cu2I5 0D Electronic Nanostructures for Ultraviolet-Emitting Applications},

author = {Andre Luiz Martins Freitas and Aryane Tofanello and Fernando Pereira Sabino and Marissol Rodrigues Felez and Eliane Aparecida Morais and Sergio Brochsztain and Jose Javier Sáez Acuña and Gustavo Martini Dalpian and J. A. Souza},

url = {https://pubs.acs.org/doi/abs/10.1021/acsanm.3c00242},

doi = {10.1021/acsanm.3c00242},

issn = {2574-0970},

year  = {2023},

date = {2023-05-12},

urldate = {2023-05-12},

journal = {ACS Appl. Nano Mater.},

volume = {6},

number = {9},

pages = {7196--7205},

publisher = {American Chemical Society (ACS)},

abstract = {The potential to produce ultraviolet (UV) light-emitting devices has attracted significant interest in interdisciplinary fields, particularly in the use of 0D halide nanostructures due to their straightforward synthesis methods and exceptional efficiency in optoelectronics. Here, we present a systematic study involving nanostructure synthesis and significant changes in the electronic structure caused by finite-size effects. We have focused on the investigation of size effects on the UV-light emitting properties of all-inorganic Cs3Cu2I5 halide. We observe that bulk particles present a pronounced bright-blue emission at 440 nm with a high quantum yield of 80%. Very small quantum dots nanostructures (6–10 nm) reveal a significant shift of the photoluminescence peak down to ∼395 nm, close to the UV-A region, but with a quantum yield reduction of 10%. Surface engineering to obtain very small nanoparticles free from defects at the nanocrystal surface is crucial for maintaining a high quantum efficiency, allowing their use in UV-emitting devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ganharul2022c,

title = {Outstanding cooperation of all-inorganic CsPbI3 perovskite with TiO2 forming composites and heterostructures for photodegradation},

author = {Grace Kelly Q. Ganharul and Aryane Tofanello and Ariany Bonadio and André L. M. Freitas and Márcia T. Escote and André S. Polo and Iseli L. Nantes-Cardoso and J. A. Souza},

url = {https://link.springer.com/article/10.1007/s10853-022-07737-0},

doi = {10.1007/s10853-022-07737-0},

issn = {1573-4803},

year  = {2022},

date = {2022-09-00},

urldate = {2022-09-00},

journal = {J Mater Sci},

volume = {57},

number = {36},

pages = {17363--17379},

publisher = {Springer Science and Business Media LLC},

abstract = {Semiconductor materials have a great potential to be used as a photocatalyst in several applications from dye degradation and water treatment up to solar cells. All-inorganic halide perovskite CsPbI3 and TiO2 with anatase structure were synthesized, studied, and compared as single samples and also forming heterostructures and composites. Structural, morphological, and optical characterizations reveal the successful synthesis of CsPbI3 and TiO2 compounds and the formation of both composites and heterostructures CsPbI3/TiO2. Methylene blue organic dye was used as a model for the study and evaluation of the photocatalytic activity exhibited by the produced semiconducting samples. The photocatalytic activity for MB degradation in methanol was investigated separately for TiO2 and CsPbI3 and their formation as composites and heterostructures. We have observed that when CsPbI3 perovskite is combined with TiO2, a cooperative mechanism involving the formation of intermediate phases promotes photobleaching with a kinetic constant rate much higher than both compounds separated or forming heterostructures. The CsPbI3/TiO2 causes MB mineralization by an oxygen-dependent mechanism. On the other hand, very high constant rate of the MB photodegradation can be observed by CsPbI3 perovskite even in a solution without the presence of dissolved oxygen. The presence of structural defects interstitials, vacancies, and under-coordinated Pb2+ ions on the surface of the perovskite particles may be formed during light irradiation and act as catalytic centers. The kinetic constant rate and the mechanism of MB photobleaching and the occurrence of dye mineralization can be tuned in feasible by simple strategies involving the formation of heterostructure and composites.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Freitas2022b,

title = {Unraveling the effect of mixed charge carrier on the electrical conductivity in MAPbBr3 perovskite due to ions incorporation},

author = {Andre L. M. Freitas and Aryane Tofanello and Ariany Bonadio and J. A. Souza},

url = {https://link.springer.com/article/10.1007/s10854-022-08687-8},

doi = {10.1007/s10854-022-08687-8},

issn = {1573-482X},

year  = {2022},

date = {2022-08-00},

urldate = {2022-08-00},

journal = {J Mater Sci: Mater Electron},

volume = {33},

number = {23},

pages = {18327--18344},

publisher = {Springer Science and Business Media LLC},

abstract = {We have investigated the role of H+, Bi3+, and Sb3+ ions incorporation on the structural, morphological, optical, and transport properties in MAPbBr3 perovskite. A comprehensive study of the Bi/Sb- and H+-doped samples on electrical transport properties as a function of light, and within the solar cell working temperature window reveals a hidden effect on the charge transport. Interestingly, Bi-doped samples produced at different acid concentrations showed an anomalous photoconductivity effect at room temperature accompanied by a suppression of photoluminescence emission peak suggesting the creation of non-radiative energy levels. Our results put forward that the coexistence of Bi3+ and interstitial protons in the doped samples collaborate to the detriment of electrical conductivity causing a large hysteresis during the thermal cycles, differently from the observed for the Sb-doped counterpart. Therefore, we pointed out that the presence of H+ ions in high concentration during the synthetic procedure associated with bismuth ions brings about harmful hysteresis and anomalous photoconductivity effects close to the solar cell working temperature which in turn causes degradation and low stability of the devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Caturello2022,

title = {Pressure-Induced Stabilization of Sodium Halide Perovskites},

author = {Naidel A. M. S. Caturello and Fernando P. Sabino and J. A. Souza and Gustavo M. Dalpian},

url = {https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.2c00824},

doi = {10.1021/acs.jpcc.2c00824},

issn = {1932-7455},

year  = {2022},

date = {2022-03-03},

urldate = {2022-03-03},

journal = {J. Phys. Chem. C},

volume = {126},

number = {8},

pages = {4248--4254},

publisher = {American Chemical Society (ACS)},

abstract = {Halide perovskites with the chemical formula ABX3 are promising materials for solar energy harvesting, with their A-site playing an important role in giving stability for the 3D corner-sharing octahedron BX6, forming the perovskite structure. In its inorganic family, the perovskite A-site is usually occupied by Cs, and when lighter atoms such as Na and K are introduced, the perovskite structure becomes unstable compared to other crystal structures. Here, we show that relatively low pressures, ranging from 6.1 to 7.0 GPa, can stabilize Na-based perovskites. We have also found that the band gap energy of these compounds decreases as a function of pressure, revealing a transition from semiconducting to metallic behavior at pressures larger than 50 GPa. These results present a pathway for the stabilization of new perovskites that can be extended to other systems composed of small ions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Acosta2022,

title = {Machine Learning Study of the Magnetic Ordering in 2D Materials},

author = {Carlos Mera Acosta and Elton Ogoshi and J. A. Souza and Gustavo M. Dalpian},

url = {https://pubs.acs.org/doi/abs/10.1021/acsami.1c21558},

doi = {10.1021/acsami.1c21558},

issn = {1944-8252},

year  = {2022},

date = {2022-02-23},

urldate = {2022-02-23},

journal = {ACS Appl. Mater. Interfaces},

volume = {14},

number = {7},

pages = {9418--9432},

publisher = {American Chemical Society (ACS)},

abstract = {Magnetic materials have been applied in a large variety of technologies, from data storage to quantum devices. The development of two-dimensional (2D) materials has opened new arenas for magnetic compounds, even when classical theories discourage their examination. Here we propose a machine-learning-based strategy to predict and understand magnetic ordering in 2D materials. This strategy couples the prediction of the existence of magnetism in 2D materials using a random forest and the Shapley additive explanations method with material maps defined by atomic features predicting the magnetic ordering (ferromagnetic or antiferromagnetic). While the random forest model predicts magnetism with an accuracy of 86%, the material maps obtained by the sure independence screening and sparsifying method have an accuracy of ∼90% in predicting the magnetic ordering. Our model indicates that 3d transition metals, halides, and structural clusters with regular transition-metal sublattices have a positive contribution in the total weight deciding the existence of magnetism in 2D compounds. This behavior is associated with the competition between crystal field and exchange splitting. The machine learning model also indicates that the atomic spin orbit coupling (SOC) is a determinant feature for the identification of the patterns separating ferro- from antiferromagnetic order. The proposed strategy is used to identify novel 2D magnetic compounds that, together with the fundamental trends in the chemical and structural space, pave novel routes for experimental exploration.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tofanello2022b,

title = {Magnetism in a 2D Hybrid Ruddlesden–Popper Perovskite through Charge Redistribution Driven by an Organic Functional Spacer},

author = {A. Tofanello and A. L. M. Freitas and T. B. de Queiroz and A. Bonadio and H. Martinho and J. A. Souza},

url = {https://pubs.acs.org/doi/abs/10.1021/acs.jpclett.1c04216},

doi = {10.1021/acs.jpclett.1c04216},

issn = {1948-7185},

year  = {2022},

date = {2022-02-17},

urldate = {2022-02-17},

journal = {J. Phys. Chem. Lett.},

volume = {13},

number = {6},

pages = {1406--1415},

publisher = {American Chemical Society (ACS)},

abstract = {Two-dimensional Ruddlesden–Popper (RP) perovskites are emerging materials offering great synthetic versatility and remarkable features due to the tunability of their crystal structure. We present a novel strategy to provide magnetism in a 2D RP perovskite using histidine molecules as a spacer, which could induce charge rebalancing at the interface of the inorganic layer. We observe that the amide and imidazole groups are close to Pb ions. The interaction with the imidazole indicates that this functional group, possibly assisted by the carboxyl close to the vicinity of the amine terminal, is inducing charge rearrangement from Pb2+ to paramagnetic Pb3+ ions, resulting in a positive magnetic moment. This magnetized 2D hybrid perovskites can be classified as a novel class of promising materials showing a magnetic moment at their interface, which may result in intriguing physical properties due to a delicate balance between magnetism and a quantum well confinement effect in the inorganic layer.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zanata2022c,

title = {Iron oxide nanoparticles–cellulose: a comprehensive insight on nanoclusters formation},

author = {Leonardo Zanata and Aryane Tofanello and Herculano S. Martinho and J. A. Souza and Derval S. Rosa},

doi = {10.1007/s10853-021-06564-z},

issn = {1573-4803},

year  = {2022},

date = {2022-01-00},

urldate = {2022-01-00},

journal = {J Mater Sci},

volume = {57},

number = {1},

pages = {324--335},

publisher = {Springer Science and Business Media LLC},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bonadio2022,

title = {Hybrid MAPbI3 Perovskite Growth Mechanism from Irregular Particles to Cuboid and Hopper-Type Morphologies},

author = {Ariany Bonadio and J. A. Souza},

url = {https://www.scielo.br/j/jbchs/a/zDXFHd8fLFjXLNCjMZTrVmr/},

doi = {10.21577/0103-5053.20220057},

issn = {0103-5053},

year  = {2022},

date = {2022-00-00},

urldate = {2022-00-00},

journal = {J. Braz. Chem. Soc.},

publisher = {Sociedade Brasileira de Quimica (SBQ)},

abstract = {Methylammonium lead iodide (MAPbI3), used as light-harvesting layer in solar cell devices, has attracted great attention from scientific community due to its excellent photovoltaic performance. In this work, we have shown a comprehensive study on the hybrid organic-inorganic MAPbI3 perovskite growth mechanism from irregular small particles to cuboid shape followed by hopper-type morphology through a systematically change on both the temperature and lead source concentration during the solution synthesis process. Indeed, we have observed very interesting hopper growth resulting in a pyramid-hollow like morphology. We have explained the morphology evolution by taking into account thermodynamics growth, which compete with kinetics growth under nonequilibrium conditions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rodrigues2021b,

title = {Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs2AgSbCl6 Double Perovskite},

author = {João Elias F. S. Rodrigues and Carlos A. Escanhoela and Brenda Fragoso and Guilherme Sombrio and Mateus M. Ferrer and Consuelo Álvarez-Galván and Maria Teresa Fernández-Díaz and J. A. Souza and Fabio F. Ferreira and Carlos Pecharromán and José Antonio Alonso},

url = {https://pubs.acs.org/doi/full/10.1021/acs.iecr.1c02188},

doi = {10.1021/acs.iecr.1c02188},

issn = {1520-5045},

year  = {2021},

date = {2021-12-29},

urldate = {2021-12-29},

journal = {Ind. Eng. Chem. Res.},

volume = {60},

number = {51},

pages = {18918--18928},

publisher = {American Chemical Society (ACS)},

abstract = {Despite the rapid development and enormous success of organic–inorganic hybrid halide perovskites (AB′X3), such as CH3NH3PbI3 as absorbers for perovskite-based solar cells (PSCs), the commercial applications of photovoltaic techniques still face several challenges, such as decomposition when exposed to light and moisture, and lead toxicity. On the other hand, the double perovskites (A2B′B″X6) are derived from the AB′X3 when half of the octahedrally coordinated B′-cations are partially replaced by the suitable B″-cations. They are attracting attention due to a new design strategy to replace Pb2+ ions with the couple of a monovalent M+ ion and a trivalent M3+ ion, leading to a new family of quaternary double perovskites. In this way, we aim to synthesize and characterize Cs2AgSbCl6 powdered samples, designed for solar cell applications. The crystalline phase and morphological features are investigated by X-ray powder diffraction (XRPD), neutron powder diffraction (NPD), scanning electron microscopy (SEM) in complement with UV–vis spectroscopy, showing a suitable band gap of 2.7 eV. The solution synthesis method proved to be efficient in obtaining polycrystalline-Cs2AgSbCl6 samples in a cubic ordered phase. DFT calculations also provided insights on the vibrational properties of Cs2AgSbCl6, corroborating the experimental data and elucidating the optical activity of Raman and infrared modes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ganharul2021c,

title = {Disclosing the hidden presence of Ti3+ ions in different TiO2 crystal structures synthesized at low temperature and photocatalytic evaluation by methylene blue photobleaching},

author = {Grace Kelly Q. Ganharul and Aryane Tofanello and Ariany Bonadio and André L. M. Freitas and Márcia T. Escote and André S. Polo and Iseli L. Nantes-Cardoso and J. A. Souza},

url = {https://link.springer.com/article/10.1557/s43578-021-00342-y},

doi = {10.1557/s43578-021-00342-y},

issn = {2044-5326},

year  = {2021},

date = {2021-08-28},

urldate = {2021-08-28},

journal = {Journal of Materials Research},

volume = {36},

number = {16},

pages = {3353--3365},

publisher = {Springer Science and Business Media LLC},

abstract = {We have performed a comprehensive study on the relationship among different crystal structures of TiO2, appearance of self-doping Ti3+ ions at low synthesis temperature, and photodegradation efficiency of the organic dye methylene blue (MB). Samples with anatase and rutile phase of TiO2 were synthesized by microwave assisted hydrothermal method. The anatase structured samples promote faster MB photobleaching in comparison with the rutile one. Electron paramagnetic resonance and X-ray photoelectron spectroscopies disclosed the presence of self-doping Ti3+ ions in the anatase that are completely absent in the rutile phase. The creation of these Ti3+ ions driven by anatase structure due to its lower vacancy formation energy induces mid-gap states within the band-gap of TiO2, which in turn can enhance the visible light absorption. Understanding the precursors at low synthesis temperatures of defects and self-doping formations can shed light on both the efficiency evolution and photocatalytic nature of this important semiconducting material.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bonadio2021d,

title = {Tailoring the Optical, Electronic, and Magnetic Properties of MAPbI3 through Self-Assembled Fe Incorporation},

author = {A. Bonadio and F. P. Sabino and A. Tofanello and A. L. M. Freitas and V. G. de Paula and G. M. Dalpian and J. A. Souza},

url = {https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.1c03955},

doi = {10.1021/acs.jpcc.1c03955},

issn = {1932-7455},

year  = {2021},

date = {2021-07-22},

urldate = {2021-07-22},

journal = {J. Phys. Chem. C},

volume = {125},

number = {28},

pages = {15636--15646},

publisher = {American Chemical Society (ACS)},

abstract = {We have produced Fe-doped paramagnetic MAPbI3 microwires by using a novel strategy involving a self-assembly growth process of [PbI6]4– octahedral chains in the presence of liquid water. Structural and morphological studies confirmed that after the dissociation and recrystallization process, the doped samples preserved both the perovskite structure with a tetragonal phase and a microwire shape, while X-ray photoelectron spectroscopy revealed the presence of mixed-valence Fe3+/Fe2+ ions with negligible change in the PbI6 cage environment and the maximum valence band position. From first-principles calculations, we determined that Fe2+ ions are localized in the interstitial site while Fe3+ ones are substitutional on Pb sites. The very high mobility and static dielectric constant, achieved by photogenerated charge carriers in MAPbI3, are suppressed for Fe-doped MAPbI3 samples. These results are discussed based on a nonradiative recombination process assisted by phonons that is activated by the inclusion of the Fe ions. Our ab initio calculations support this model that can be also used to explain the quenching of the photoluminescence emission peaks. The successful insertion of dopants that can tune the perovskite’s physical properties is important to the development of functional devices and is also able to open new potential applications such as in magnetic/semiconducting devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bonadio2021f,

title = {Tailoring the Optical, Electronic, and Magnetic Properties of MAPbI3 through Self-Assembled Fe Incorporation},

author = {A. Bonadio and F. P. Sabino and A. Tofanello and A. L. M. Freitas and V. G. de Paula and Gustavo M. Dalpian and J. A. Souza},

url = {https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.1c03955},

doi = {10.1021/acs.jpcc.1c03955},

issn = {1932-7455},

year  = {2021},

date = {2021-07-22},

urldate = {2021-07-22},

journal = {J. Phys. Chem. C},

volume = {125},

number = {28},

pages = {15636--15646},

publisher = {American Chemical Society (ACS)},

abstract = {We have produced Fe-doped paramagnetic MAPbI3 microwires by using a novel strategy involving a self-assembly growth process of [PbI6]4– octahedral chains in the presence of liquid water. Structural and morphological studies confirmed that after the dissociation and recrystallization process, the doped samples preserved both the perovskite structure with a tetragonal phase and a microwire shape, while X-ray photoelectron spectroscopy revealed the presence of mixed-valence Fe3+/Fe2+ ions with negligible change in the PbI6 cage environment and the maximum valence band position. From first-principles calculations, we determined that Fe2+ ions are localized in the interstitial site while Fe3+ ones are substitutional on Pb sites. The very high mobility and static dielectric constant, achieved by photogenerated charge carriers in MAPbI3, are suppressed for Fe-doped MAPbI3 samples. These results are discussed based on a nonradiative recombination process assisted by phonons that is activated by the inclusion of the Fe ions. Our ab initio calculations support this model that can be also used to explain the quenching of the photoluminescence emission peaks. The successful insertion of dopants that can tune the perovskite’s physical properties is important to the development of functional devices and is also able to open new potential applications such as in magnetic/semiconducting devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bonadio2021c,

title = {Entropy-driven stabilization of the cubic phase of MaPbI3 at room temperature},

author = {A. Bonadio and C. A. Escanhoela and F. P. Sabino and G. Sombrio and V. G. de Paula and F. F. Ferreira and A. Janotti and G. M. Dalpian and J. A. Souza},

url = {https://pubs.rsc.org/en/content/articlehtml/2021/ta/d0ta10492b},

doi = {10.1039/d0ta10492b},

issn = {2050-7496},

year  = {2021},

date = {2021-01-19},

urldate = {2021-01-19},

journal = {J. Mater. Chem. A},

volume = {9},

number = {2},

pages = {1089--1099},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {Methylammonium lead iodide (MAPbI3) is an important light-harvesting semiconducting material for solar-cell devices. We investigate the effect of long thermal annealing in an inert atmosphere of compacted MAPbI3 perovskite powders. The microstructure morphology of the MAPbI3 annealed samples reveals a well-defined grain boundary morphology. The voids and neck-connecting grains are observed throughout the samples, indicating a well-sintered process due to mass diffusion transfer through the grain boundary. The long 40 h thermal annealing at T = 522 K (kBT = 45 meV) causes a significant shift in the structural phase transition, stabilizing the low-electrical conductivity and high-efficiency cubic structure at room temperature. The complete disordered orientation of MA cations maximizes the entropy of the system, which, in turn, increases the Pb–I–Pb angle close to 180°. The MA rotation barrier and entropy analysis determined through DFT calculations suggest that the configurational entropy is a function of the annealing time. The disordered organic molecules are quenched and become kinetically trapped in the cubic phase down to room temperature. We propose a new phase diagram for this important system combining different structural phases as a function of temperature with annealing time for MAPbI3. The absence of the coexistence of different structural phases, leading to thermal hysteresis, can significantly improve the electrical properties of the solar cell devices. Through an entropy-driven stabilization phenomenon, we offer an alternative path for improving the maintenance, toughness, and efficiency of the optoelectronic devices by removing the microstructural stress brought by the structural phase transformation within the solar cell working temperature range.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bonadio2021e,

title = {Entropy-driven stabilization of the cubic phase of MaPbI3 at room temperature},

author = {A. Bonadio and C. A. Escanhoela and F. P. Sabino and G. Sombrio and V. G. de Paula and F. F. Ferreira and A. Janotti and Gustavo M. Dalpian and J. A. Souza},

url = {https://pubs.rsc.org/en/content/articlehtml/2021/ta/d0ta10492b},

doi = {10.1039/d0ta10492b},

issn = {2050-7496},

year  = {2021},

date = {2021-01-19},

urldate = {2021-01-19},

journal = {J. Mater. Chem. A},

volume = {9},

number = {2},

pages = {1089--1099},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {Methylammonium lead iodide (MAPbI3) is an important light-harvesting semiconducting material for solar-cell devices. We investigate the effect of long thermal annealing in an inert atmosphere of compacted MAPbI3 perovskite powders. The microstructure morphology of the MAPbI3 annealed samples reveals a well-defined grain boundary morphology. The voids and neck-connecting grains are observed throughout the samples, indicating a well-sintered process due to mass diffusion transfer through the grain boundary. The long 40 h thermal annealing at T = 522 K (kBT = 45 meV) causes a significant shift in the structural phase transition, stabilizing the low-electrical conductivity and high-efficiency cubic structure at room temperature. The complete disordered orientation of MA cations maximizes the entropy of the system, which, in turn, increases the Pb–I–Pb angle close to 180°. The MA rotation barrier and entropy analysis determined through DFT calculations suggest that the configurational entropy is a function of the annealing time. The disordered organic molecules are quenched and become kinetically trapped in the cubic phase down to room temperature. We propose a new phase diagram for this important system combining different structural phases as a function of temperature with annealing time for MAPbI3. The absence of the coexistence of different structural phases, leading to thermal hysteresis, can significantly improve the electrical properties of the solar cell devices. Through an entropy-driven stabilization phenomenon, we offer an alternative path for improving the maintenance, toughness, and efficiency of the optoelectronic devices by removing the microstructural stress brought by the structural phase transformation within the solar cell working temperature range.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}