Our list of Publications
2026
Brandão, Zeno De C.; Rodrigues, Murillo H. De M.; Nogueira, Ana F.; Zagonel, Luiz F.; Marques, Francisco Das C.
Rationalizing NiO$_textrm textitx $ Processing through XPS Chemical Analysis: A Case Study on p-i-n Perovskite Solar Cells Journal Article
In: ACS Applied Energy Materials, pp. acsaem.5c04101, 2026, ISSN: 2574-0962, 2574-0962.
Abstract | Links | BibTeX | Tags:
@article{brandao_rationalizing_2026,
title = {Rationalizing NiO$_textrm textitx $ Processing through XPS Chemical Analysis: A Case Study on p-i-n Perovskite Solar Cells},
author = {Zeno De C. Brandão and Murillo H. De M. Rodrigues and Ana F. Nogueira and Luiz F. Zagonel and Francisco Das C. Marques},
url = {https://pubs.acs.org/doi/10.1021/acsaem.5c04101},
doi = {10.1021/acsaem.5c04101},
issn = {2574-0962, 2574-0962},
year = {2026},
date = {2026-04-01},
urldate = {2026-04-14},
journal = {ACS Applied Energy Materials},
pages = {acsaem.5c04101},
abstract = {Nonstoichiometric nickel oxide (NiOx) is a promising inorganic hole transport layer (HTL) for perovskite solar cells (PSCs), yet its surface chemistry lacks definitive modeling. Here, we investigate the evolution of chemical species and optoelectronic properties in ultrathin NiOx films deposited via ion beam sputter deposition (IBSD) under various thermal and oxidative treatments. Using in situ and ex situ X-ray photoelectron spectroscopy (XPS), we resolve up to seven distinct oxygen species in the core level O 1s spectra, including oxygen bound Niv3a+c, Ni(OH)2, NiOOH, and interstitial oxygen (O−). Our results support that p-type conductivity, transparency, and band alignment in NiOx are governed directly by the concentration of Ni3+ related to nickel vacancies. Additionally, UV/Ozone exposure is shown to introduce NiOOH, enhancing surface wettability and increasing the work function by the creation of a surface dipole, improving charge extraction but reducing the long-term stability of NiOx films due to hygroscopic decomposition. High temperature deposition at 300 °C yields the best balance between optoelectronic properties, recombination, and most stable surface chemistry, yielding the best photovoltaic performance among tested conditions. This work establishes a robust spectroscopic framework for studying and engineering vacancy-controlled NiOx interfaces, with implications for improving the stability and efficiency of inorganic HTLs in p-i-n PSCs and other applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Nonstoichiometric nickel oxide (NiOx) is a promising inorganic hole transport layer (HTL) for perovskite solar cells (PSCs), yet its surface chemistry lacks definitive modeling. Here, we investigate the evolution of chemical species and optoelectronic properties in ultrathin NiOx films deposited via ion beam sputter deposition (IBSD) under various thermal and oxidative treatments. Using in situ and ex situ X-ray photoelectron spectroscopy (XPS), we resolve up to seven distinct oxygen species in the core level O 1s spectra, including oxygen bound Niv3a+c, Ni(OH)2, NiOOH, and interstitial oxygen (O−). Our results support that p-type conductivity, transparency, and band alignment in NiOx are governed directly by the concentration of Ni3+ related to nickel vacancies. Additionally, UV/Ozone exposure is shown to introduce NiOOH, enhancing surface wettability and increasing the work function by the creation of a surface dipole, improving charge extraction but reducing the long-term stability of NiOx films due to hygroscopic decomposition. High temperature deposition at 300 °C yields the best balance between optoelectronic properties, recombination, and most stable surface chemistry, yielding the best photovoltaic performance among tested conditions. This work establishes a robust spectroscopic framework for studying and engineering vacancy-controlled NiOx interfaces, with implications for improving the stability and efficiency of inorganic HTLs in p-i-n PSCs and other applications.
Burgos-Caminal, Andrés; Vale, Brener R. C.; Fonseca, André F. V.; Hidalgo, Juan F.; Collet, Elisa P. P.; García, Lázaro; Vega-Mayoral, Víctor; Garcia-Orrit, Saül; Arnay, Iciar; Cabanillas-González, Juan; Simonelli, Laura; Nogueira, Ana Flávia; Schiavon, Marco Antônio; Penfold, Thomas J.; Padilha, Lazaro A.; Gawelda, Wojciech
In: Chemistry of Materials, vol. 38, no. 6, pp. 2601–2612, 2026, ISSN: 0897-4756, 1520-5002.
Abstract | Links | BibTeX | Tags:
@article{burgos-caminal_unveiling_2026,
title = {Unveiling Zn Incorporation in CuInS$_textrm2$ Quantum Dots: X-ray and Optical Analysis of Doping Effects, Structural Modifications, and Surface Passivation},
author = {Andrés Burgos-Caminal and Brener R. C. Vale and André F. V. Fonseca and Juan F. Hidalgo and Elisa P. P. Collet and Lázaro García and Víctor Vega-Mayoral and Saül Garcia-Orrit and Iciar Arnay and Juan Cabanillas-González and Laura Simonelli and Ana Flávia Nogueira and Marco Antônio Schiavon and Thomas J. Penfold and Lazaro A. Padilha and Wojciech Gawelda},
url = {https://pubs.acs.org/doi/10.1021/acs.chemmater.5c01878},
doi = {10.1021/acs.chemmater.5c01878},
issn = {0897-4756, 1520-5002},
year = {2026},
date = {2026-03-01},
urldate = {2026-04-14},
journal = {Chemistry of Materials},
volume = {38},
number = {6},
pages = {2601–2612},
abstract = {CuInS2 quantum dots (QDs) have gained significant attention owing to their remarkable broadband emission, making them desirable for various optoelectronic applications requiring efficient luminescent nanomaterials. However, maximizing radiative recombination in CuInS2 QDs necessitates minimizing intragap trap states. A common approach involves the introduction of Zn during the synthesis, which typically promotes the formation of a ZnS shell that passivates the QD surface. Despite its importance, the characterization and quantification of Zn incorporation using conventional techniques, such as optical spectroscopy or electron microscopy, remains challenging. In this study, we utilized X-ray absorption spectroscopy, in both X-ray absorption near-edge structure and extended X-ray absorption fine structure spectral ranges, to investigate Zn incorporation into CuInS2 QDs, probing at the Zn, S, and Cu K-edges. This approach allowed us to detect the formation of a ZnS surface shell, tentatively quantifying its thickness, and to distinguish between Zn as a substituent at the shell or as an interstitial defect. Additionally, we explored the dynamical properties of CuInS2 QDs using time-resolved optical spectroscopies, particularly in the presence of electron and hole acceptors (benzoquinone and phenothiazine), observing that hole transfer is highly sensitive to shell thickness. These results provide deeper insights into the Zn-induced shell.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
CuInS2 quantum dots (QDs) have gained significant attention owing to their remarkable broadband emission, making them desirable for various optoelectronic applications requiring efficient luminescent nanomaterials. However, maximizing radiative recombination in CuInS2 QDs necessitates minimizing intragap trap states. A common approach involves the introduction of Zn during the synthesis, which typically promotes the formation of a ZnS shell that passivates the QD surface. Despite its importance, the characterization and quantification of Zn incorporation using conventional techniques, such as optical spectroscopy or electron microscopy, remains challenging. In this study, we utilized X-ray absorption spectroscopy, in both X-ray absorption near-edge structure and extended X-ray absorption fine structure spectral ranges, to investigate Zn incorporation into CuInS2 QDs, probing at the Zn, S, and Cu K-edges. This approach allowed us to detect the formation of a ZnS surface shell, tentatively quantifying its thickness, and to distinguish between Zn as a substituent at the shell or as an interstitial defect. Additionally, we explored the dynamical properties of CuInS2 QDs using time-resolved optical spectroscopies, particularly in the presence of electron and hole acceptors (benzoquinone and phenothiazine), observing that hole transfer is highly sensitive to shell thickness. These results provide deeper insights into the Zn-induced shell.
de Matos Rodrigues, Murillo Henrique; Sobrinho, Josiane A.; Machado, Arthur Pignataro; Brandao, Zeno C.; Barcelos, Ingrid D.; Labre, Cilene; Szostak, Rodrigo; Nogueira, Ana Flávia
Tuning Structure and Performance of 2D/3D Perovskites by Alkyl Chain Length Engineering Journal Article
In: ACS Energy Letters, vol. 0, no. 0, pp. null, 2026.
Abstract | Links | BibTeX | Tags:
@article{doi:10.1021/acsenergylett.5c02838,
title = {Tuning Structure and Performance of 2D/3D Perovskites by Alkyl Chain Length Engineering},
author = {Murillo Henrique de Matos Rodrigues and Josiane A. Sobrinho and Arthur Pignataro Machado and Zeno C. Brandao and Ingrid D. Barcelos and Cilene Labre and Rodrigo Szostak and Ana Flávia Nogueira},
url = {https://doi.org/10.1021/acsenergylett.5c02838},
doi = {10.1021/acsenergylett.5c02838},
year = {2026},
date = {2026-02-01},
urldate = {2026-02-09},
journal = {ACS Energy Letters},
volume = {0},
number = {0},
pages = {null},
abstract = {Bulky 2D alkylammonium cations in metal halide perovskites offer a route to improve both structural stability and optoelectronic performance. This study systematically explores the incorporation of alkylammonium iodides with different chain lengths─dodecylammonium (C12), hexadecylammonium (C16), and octadecylammonium (C18)─into perovskite films for solar cells. Using spectroscopic and nanoscale characterization techniques, we show that C12 provides the best results: enhanced [111] orientation, reduced nonradiative recombination, uniform cation distribution, and improved vertical conductivity. Nanoscale X-ray diffraction and AFM-based infrared spectroscopy revealed that intermediate chain lengths enable favorable lattice expansion and interfacial passivation without hindering crystal growth. Solar cells based on C12-modified films reached power conversion efficiencies over 20%, surpassing both pristine and longer-chain formulations. These findings demonstrate that tuning alkyl chain length is an effective molecular design strategy to guide perovskite crystallization and improve device performance and stability.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Bulky 2D alkylammonium cations in metal halide perovskites offer a route to improve both structural stability and optoelectronic performance. This study systematically explores the incorporation of alkylammonium iodides with different chain lengths─dodecylammonium (C12), hexadecylammonium (C16), and octadecylammonium (C18)─into perovskite films for solar cells. Using spectroscopic and nanoscale characterization techniques, we show that C12 provides the best results: enhanced [111] orientation, reduced nonradiative recombination, uniform cation distribution, and improved vertical conductivity. Nanoscale X-ray diffraction and AFM-based infrared spectroscopy revealed that intermediate chain lengths enable favorable lattice expansion and interfacial passivation without hindering crystal growth. Solar cells based on C12-modified films reached power conversion efficiencies over 20%, surpassing both pristine and longer-chain formulations. These findings demonstrate that tuning alkyl chain length is an effective molecular design strategy to guide perovskite crystallization and improve device performance and stability.
Fonseca, André F. V.; Frolova, Lyubov A.; Troshin, Pavel A.; Yuan, Jianyu; Nogueira, Ana F.
Perovskites beyond efficiency: stability challenges from space to Earth Journal Article
In: Energy Advances, pp. 10.1039.D5YA00315F, 2026, ISSN: 2753-1457.
Abstract | Links | BibTeX | Tags:
@article{fonseca_perovskites_2026,
title = {Perovskites beyond efficiency: stability challenges from space to Earth},
author = {André F. V. Fonseca and Lyubov A. Frolova and Pavel A. Troshin and Jianyu Yuan and Ana F. Nogueira},
url = {https://xlink.rsc.org/?DOI=D5YA00315F},
doi = {10.1039/D5YA00315F},
issn = {2753-1457},
year = {2026},
date = {2026-01-01},
urldate = {2026-04-14},
journal = {Energy Advances},
pages = {10.1039.D5YA00315F},
abstract = {Metal halide perovskites excel under extreme space radiation but remain vulnerable to terrestrial conditions, especially thermal cycling. Advancing devices requires collaboration, interface passivation, quantum-dot integration, and
in situ
studies.
,
To advance metal halide perovskite (MHP) optoelectronics beyond efficiency, international collaboration is essential, with an emphasis on stability, cost, and scalability. MHPs demonstrate remarkable stability in extreme space-level radiation; nevertheless, their stability under everyday conditions, particularly when exposed to humidity and thermal cycling, remains a significant challenge. Strategies such as low-dimensional interface passivation, quantum-dot integration, and
in situ
synchrotron studies are among the methods emphasized in this perspective to mitigate these problems. We propose pathways of collaborative research aimed at accelerating the development of durable, high-performance perovskite devices by synthesizing insights from the broader literature in conjunction with findings from a BRICS joint initiative project.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Metal halide perovskites excel under extreme space radiation but remain vulnerable to terrestrial conditions, especially thermal cycling. Advancing devices requires collaboration, interface passivation, quantum-dot integration, and
in situ
studies.
,
To advance metal halide perovskite (MHP) optoelectronics beyond efficiency, international collaboration is essential, with an emphasis on stability, cost, and scalability. MHPs demonstrate remarkable stability in extreme space-level radiation; nevertheless, their stability under everyday conditions, particularly when exposed to humidity and thermal cycling, remains a significant challenge. Strategies such as low-dimensional interface passivation, quantum-dot integration, and
in situ
synchrotron studies are among the methods emphasized in this perspective to mitigate these problems. We propose pathways of collaborative research aimed at accelerating the development of durable, high-performance perovskite devices by synthesizing insights from the broader literature in conjunction with findings from a BRICS joint initiative project.
in situ
studies.
,
To advance metal halide perovskite (MHP) optoelectronics beyond efficiency, international collaboration is essential, with an emphasis on stability, cost, and scalability. MHPs demonstrate remarkable stability in extreme space-level radiation; nevertheless, their stability under everyday conditions, particularly when exposed to humidity and thermal cycling, remains a significant challenge. Strategies such as low-dimensional interface passivation, quantum-dot integration, and
in situ
synchrotron studies are among the methods emphasized in this perspective to mitigate these problems. We propose pathways of collaborative research aimed at accelerating the development of durable, high-performance perovskite devices by synthesizing insights from the broader literature in conjunction with findings from a BRICS joint initiative project.
2025
Soares, Leonardo C.; Lima, Vanderlei S.; Alvim, Jéssica C.; Macedo, Nadia G.; Ali, Mian A.; Silva, Bruno L.; Nogueira, Ana F.; Chansai, Sarayute; Hardacre, Christopher; Longo, Claudia
Photoelectrochemical-Unassisted Glycerol Oxidation Coupled with CO2 Reduction to Value-Added Chemicals Journal Article
In: ChemCatChem, vol. n/a, no. n/a, pp. e01215, 2025.
Abstract | Links | BibTeX | Tags:
@article{https://doi.org/10.1002/cctc.202501215,
title = {Photoelectrochemical-Unassisted Glycerol Oxidation Coupled with CO2 Reduction to Value-Added Chemicals},
author = {Leonardo C. Soares and Vanderlei S. Lima and Jéssica C. Alvim and Nadia G. Macedo and Mian A. Ali and Bruno L. Silva and Ana F. Nogueira and Sarayute Chansai and Christopher Hardacre and Claudia Longo},
url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cctc.202501215},
doi = {https://doi.org/10.1002/cctc.202501215},
year = {2025},
date = {2025-12-09},
journal = {ChemCatChem},
volume = {n/a},
number = {n/a},
pages = {e01215},
abstract = {Abstract Photoelectrodes based on earth-abundant elements, FTO|BiVO4 and Nifoam|Cu2O/CuO/TiO2, were assembled in a parallel-configured flow photoelectrochemical (PEC) electrolyser and provided unassisted conversion of glycerol and CO2 into value-added chemicals under solar-simulated irradiation. The photoelectrodes PEC properties were firstly evaluated in aqueous NaHCO3 electrolyte, using platinum as auxiliary electrode, for determination of wavelength-resolved light harvesting, flat band potential, conduction and valence band edges, charge-separation and injection efficiencies. Comparison of Nifoam|Cu2O, Nifoam|Cu2O/CuO and Nifoam|Cu2O/CuO/TiO2 for PEC CO2 reduction revealed that Cu2O/CuO improved light harvesting and selectivity for ethanol production, while TiO2 protected the photocathode against photodegradation. Under illumination, the PEC flow electrolyser assembled with FTO|BiVO4 and Nifoam|Cu2O/CuO/TiO2 exhibited + 0.56 V of open-circuit photovoltage and a spontaneous short-circuit photocurrent (1.7 to 1 mA in 2 h), attributed to the suitable alignment of the band edges of these photoelectrodes. After 2 h PEC electrolysis, formate (229 µg cm−2 h−1) and glycolate (58.5 µg cm−2 h−1) were produced in the anodic compartment with faradaic efficiencies of 69% and 13%, respectively. The cathodic compartment generated 26 µg cm−2 h−1 of ethanol (FE = 32%). This flow PEC electrolyser demonstrates a proof-of-concept for a practical solar-to-chemicals production using industrial by-products as feedstocks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Photoelectrodes based on earth-abundant elements, FTO|BiVO4 and Nifoam|Cu2O/CuO/TiO2, were assembled in a parallel-configured flow photoelectrochemical (PEC) electrolyser and provided unassisted conversion of glycerol and CO2 into value-added chemicals under solar-simulated irradiation. The photoelectrodes PEC properties were firstly evaluated in aqueous NaHCO3 electrolyte, using platinum as auxiliary electrode, for determination of wavelength-resolved light harvesting, flat band potential, conduction and valence band edges, charge-separation and injection efficiencies. Comparison of Nifoam|Cu2O, Nifoam|Cu2O/CuO and Nifoam|Cu2O/CuO/TiO2 for PEC CO2 reduction revealed that Cu2O/CuO improved light harvesting and selectivity for ethanol production, while TiO2 protected the photocathode against photodegradation. Under illumination, the PEC flow electrolyser assembled with FTO|BiVO4 and Nifoam|Cu2O/CuO/TiO2 exhibited + 0.56 V of open-circuit photovoltage and a spontaneous short-circuit photocurrent (1.7 to 1 mA in 2 h), attributed to the suitable alignment of the band edges of these photoelectrodes. After 2 h PEC electrolysis, formate (229 µg cm−2 h−1) and glycolate (58.5 µg cm−2 h−1) were produced in the anodic compartment with faradaic efficiencies of 69% and 13%, respectively. The cathodic compartment generated 26 µg cm−2 h−1 of ethanol (FE = 32%). This flow PEC electrolyser demonstrates a proof-of-concept for a practical solar-to-chemicals production using industrial by-products as feedstocks.
Fonseca, André F. V.; Germano, Guilherme M.; Scalon, Lucas; Almeida, Charles A. N.; Barra, Alvaro C. C.; Ribeiro, Douglas S.; Brandão, Zeno C.; Marques, Francisco C.; Mora-Seró, Iván; Nogueira, Ana F.
CdS quantum dot interlayer engineering for enhanced SnO2/perovskite interfaces in solar cells Journal Article
In: Materials Today Chemistry, vol. 50, pp. 103238, 2025, ISSN: 2468-5194.
Abstract | Links | BibTeX | Tags:
@article{FONSECA2025103238,
title = {CdS quantum dot interlayer engineering for enhanced SnO2/perovskite interfaces in solar cells},
author = {André F. V. Fonseca and Guilherme M. Germano and Lucas Scalon and Charles A. N. Almeida and Alvaro C. C. Barra and Douglas S. Ribeiro and Zeno C. Brandão and Francisco C. Marques and Iván Mora-Seró and Ana F. Nogueira},
url = {https://www.sciencedirect.com/science/article/pii/S2468519425007281},
doi = {https://doi.org/10.1016/j.mtchem.2025.103238},
issn = {2468-5194},
year = {2025},
date = {2025-01-01},
journal = {Materials Today Chemistry},
volume = {50},
pages = {103238},
abstract = {Interfacial defects at the buried junction between the electron transport layer (ETL) and perovskite absorber critically hinder the performance of perovskite solar cells (PSCs). In this work, we report that a CdS quantum dot (QD) interlayer, deposited onto SnO2 via a scalable successive ionic layer adsorption and reaction (SILAR) method, provides a practical and scalable strategy to improve charge transport across this interface. The CdS QD layer not only suppresses oxygen vacancies but also reacts with hydroxyl groups on the SnO2 surface, thereby improving surface potential uniformity and enhancing the electron extraction rate. Impedance spectroscopy further confirms improved interface homogeneity and charge transport, which correlate with higher fill factor and short-circuit current density. As a result, CdS modification enables a ∼25 % efficiency enhancement on PSCs, highlighting the potential of QD-based interfacial engineering towards high-performance PSCs.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Interfacial defects at the buried junction between the electron transport layer (ETL) and perovskite absorber critically hinder the performance of perovskite solar cells (PSCs). In this work, we report that a CdS quantum dot (QD) interlayer, deposited onto SnO2 via a scalable successive ionic layer adsorption and reaction (SILAR) method, provides a practical and scalable strategy to improve charge transport across this interface. The CdS QD layer not only suppresses oxygen vacancies but also reacts with hydroxyl groups on the SnO2 surface, thereby improving surface potential uniformity and enhancing the electron extraction rate. Impedance spectroscopy further confirms improved interface homogeneity and charge transport, which correlate with higher fill factor and short-circuit current density. As a result, CdS modification enables a ∼25 % efficiency enhancement on PSCs, highlighting the potential of QD-based interfacial engineering towards high-performance PSCs.
Burgos-Caminal, Andrés; Vale, Brener R. C.; Fonseca, André F. V.; Collet, Elisa P. P.; Hidalgo, Juan F.; García, Lázaro; Watson, Luke; Borrell-Grueiro, Olivia; Corrales, María E.; Choi, Tae-Kyu; Katayama, Tetsuo; Fan, Dongxiao; Vega-Mayoral, Víctor; Garcia-Orrit, Saül; Nozawa, Shunsuke; Penfold, Thomas J.; Cabanillas-González, Juan; Adachi, Shin-Ichi; Bañares, Luis; Nogueira, Ana Flávia; Padilha, Lázaro A.; Schiavon, Marco Antônio; Gawelda, Wojciech
Selective Tracking of Charge Carrier Dynamics in CuInS2 Quantum Dots Journal Article
In: ACS Nano, vol. 19, no. 24, pp. 21950-21961, 2025, (PMID: 40501147).
@article{doi:10.1021/acsnano.4c18469,
title = {Selective Tracking of Charge Carrier Dynamics in CuInS2 Quantum Dots},
author = {Andrés Burgos-Caminal and Brener R. C. Vale and André F. V. Fonseca and Elisa P. P. Collet and Juan F. Hidalgo and Lázaro García and Luke Watson and Olivia Borrell-Grueiro and María E. Corrales and Tae-Kyu Choi and Tetsuo Katayama and Dongxiao Fan and Víctor Vega-Mayoral and Saül Garcia-Orrit and Shunsuke Nozawa and Thomas J. Penfold and Juan Cabanillas-González and Shin-Ichi Adachi and Luis Bañares and Ana Flávia Nogueira and Lázaro A. Padilha and Marco Antônio Schiavon and Wojciech Gawelda},
url = {https://doi.org/10.1021/acsnano.4c18469},
doi = {10.1021/acsnano.4c18469},
year = {2025},
date = {2025-01-01},
journal = {ACS Nano},
volume = {19},
number = {24},
pages = {21950-21961},
note = {PMID: 40501147},
keywords = {},
pubstate = {published},
tppubtype = {article}
}