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WEBINAR – Deciphering the emission of lead halide perovskites: insights from single CsPbBr3 nanocrystal studies

Posted on by lscherrer

Title | Deciphering the emission of lead halide perovskites: insights from single CsPbBr3 nanocrystal studies

Date | Monday, June 1, 2024, at 9:30 a.m. (UTC +2)

Speaker | M.-R. Amara (Laboratoire de Physique de l’Ecole Normale Supérieure (LPENS), Centre Nationale
de la Recherche Scientifique (CNRS))

Abstract |
Lead halide perovskite NCs (LHP NCs) are promising materials for light emission. A
better understanding of their outstanding properties in ensemble and roomtemperature
studies is complicated by broadening and averaging effects. Single NC
studies thus offer a unique probe to the band-edge electronic structure, fuelling
debates on the importance of the Rashba effect and its impact on brightness.

With cryogenic-temperature spectral studies, the size-dependent excitonic features
as well as the optical phonon replica spectrum were revealed, supporting a
predominant influence of electron-hole exchange interaction and rationalising the
variety of single NC spectra recorded.

In the temporal domain, the temperature evolution of the photoluminescence
elucidates the interplay between bright and dark exciton states, revealing reduced
bright-dark conversion characteristic of lead halide perovskites. This accounts for the
predominant bright exciton emission at all temperatures, contrasting with established
II-VI nanocrystals.

Overall, we show how single NC studies, both in the spectral and temporal domain,
have enhanced our understanding of the electronic structure and luminescence
mechanisms of lead halide perovskites.

 

Our contributions :
M.-R. Amara et al., Nano Letters 23(8) 3607 (2023)
M.-R. Amara et al., Nano Letters 24(14) 4265 (2024)

Webinar: Optical Integrated Perovskite to Silicon for Enhanced Performance

Posted on by Trong Tam Nguyen

Title | Optical Integrated Perovskite to Silicon for Enhanced Performance

Date | Tuesday, June 4, 2024, at 9:30 a.m. (UTC +2)

Speaker | Prof. Baoquan Sun (Soochow University, China)

Abstract | Lead-free halide double perovskites, have not been deemed useful thus far due to the absence of high photoluminescence quantum yield (PLQY) examples and large bandgaps. Herein, we demonstrate the doping strategy for the benchmark material of Cs2NaInCl6, achieving blue emission with near-unity PLQY and the lowest bandgap of 1.24 eV. In addition, we would like to discuss some strategies to mitigate parasitic absorption of silicon solar integrated with luminescent converter issues. We showed that part of short wavelength sunlight can be converted into a polarization electrical field by perovskite particles, which strengthens asymmetry in heterojunction solar cells through the molecule alignment process. Then, incorporating luminescent perovskite and quantum dots with high quantum yields as light converters can also enhance power conversion efficiency.

 

Références :

[1]      Liu, Yan; Dai, Xing; Zeng, Xuelian; Yuan, Xianrong; Wang, Yanan; Song, Yuhang; Chen, Haoyu; Zhang, Chao; Wang, Yong; Wan, Li; Zou, Yatao; Ning, Weihua; Sun, Baoquan, High-Efficient Blue Emission and Bandgap Engineering from Jahn–Teller Distorted Halide Double Perovskites. Advanced Optical Materials 2024, 12 (3), 2301576.
[2]      Jiang C.; Zhang G.; Hong Z.; Chen J.; Li Y.; Yuan X.; Lin Y.; Yu C.; Wang T.; Song T.; Wang Y.; Sun B., Colored Silicon Heterojunction Solar Cells Exceeding 23.5% Efficiency Enabled by Luminescent Down-Shift Quantum Dots. Advanced Material 2023, 35 (6), e2208042.

Workshop: Renewable energy and emerging technologies

Posted on by Trong Tam Nguyen

Title | Renewable energy and emerging technologies

Date | Tuesday June 4 , 2024

Place | ESPCI Paris + hybrid mode by ZOOM

Organizer | Dr Zhuyoing Chen (CNRS/ESPCI)

Program |

09h20 – 09h30 Opening
09h30 – 10h10 Baoquan Sun (Soochow University)
Optical Integrated Perovskite to Silicon for Enhanced Performance
10h10 – 10h50 Emmanuelle Deleporte (ENS Paris Saclay)
2D/3D hybrid halide perovskite heterostructures for stable and high-efficiency solar cells
10h50 – 11h10 Coffee break
11h10 – 11h50 Thierry Pauporté (IRCP)
Chemical changes occurring upon the synthesis of 2D to 3D organometal perovskite layers
11h50 – 14h00 Poster & lunch
14h00 – 14h40 Annie Colin (ESPCI)
Harvest osmotic energy from the difference in salinity between salt water (sea, lake) and fresh water (river, treated water)
14h40 – 15h20 Ruiyuan Liu (Soochow University)
Flexible ambient-energy harvesters and self-powered sensors
15h20 – 15h35 Coffee break
15h35 – 16h15 Beibei Shao (Soochow University)
High-Efficient Hydrovoltaic and Triboelectric Power Generators for
Wearable/On-skin Electronics
16h15 – 16h55 Jean-François Guillemoles (IPVF)
Photoluminescence and reliability in perovskite solar cells
16h55 – 17h00 Closing

Synergetic Exterior and Interfacial Approaches by Colloidal Carbon Quantum Dots for More Stable Perovskite Solar Cells Against UV

Posted on by Trong Tam Nguyen

Contribution: LPEM

Reference : Small. 2024, 2401505, https://doi.org/10.1002/smll.202401505 (Early view)

DOI : https://doi.org/10.1002/smll.202401505

Contacts : zhuoying.chen@espci.fr

 

Abstract :

The achievement of both efficiency and stability in perovskite solar cells (PSCs) remains a challenging and actively researched topic. In particular, among different environmental factors, ultraviolet (UV) photons play a pivotal role contributing to device degradation. In this work, by harvesting simultaneously both the optical and the structural properties of bottom-up-synthesized colloidal carbon quantum dots (CQDs), we provide a cost-effective means to circumvent the UV-induced degradation in PSCs without scarification on their power conversion efficiencies (PCEs). By exploring and optimizing the amount of CQDs and the different location/interfaces of the solar cells where CQDs are applied, we achieve a synergetic configuration where the photovoltaic performance drop due to optical loss is completely compensated by the increased perovskite crystallinity due to interfacial modification. As a result, on the optimized configurations where CQDs were applied both on the exterior front side as an optical layer and at the interface between the electron transport layer and the perovskite absorber, unencapsulated PSCs with PCEs > 20% are fabricated which can maintain up to ~ 94% of their initial PCE after 100 hours of degradation in ambient air under continuous UV illumination (5 mW cm-2).

 

Left : Schematic illustrating the combined exterior and interfacial application of bottom-up synthesized carbon quantum dots (CQDs) in a functional PSC structure. Right : Unencapsulated PSC stability under continuous UV illumination measured on devices without (control) and with CQDs applied under different configurations in air. This work highlights a cost-effective means based on CQDs to circumvent the UV-induced degradation in efficient perovskite solar cells (PSCs) without scarification on their power conversion efficiencies.

 

Charles Sidhoum (IPCMS Strasbourg) – May 6, 2024

Posted on by lscherrer

Title | Shedding Light on the Birth of Hybrid Perovskites: A Correlative Study by In Situ Electron Microscopy and Synchrotron-Based X‑ray Scattering

Date |May 6, 2024

Speaker | Charles SIDHOUM, IPCMS Strasbourg

Abstract |  Despite the amount of work carried out to optimize the optoelectronic properties of Lead halide perovskites (LHPs), there is a clear lack of comprehension of the phenomena at the origin of LHPs crystallization. The formation of LHPs, including the commonly studied methylammonium lead iodide (MAPI), by ligand-assisted reprecipitation (LARP) remains one of the main explored pathways of synthesis. This approach involved the formation of solvated intermediate phase[1] due to the use of strong coordinative solvent, such as DMF. In this study[2], we took advantage of the development of a series of advanced in-situ techniques to bring new insights into the pathway of this process that leads to MAPI perovskites from a precursor solution. First, we monitored the nucleation and growth processes of a solvated intermediate phase by correlating local information obtained by liquid-phase TEM and more global information brought by synchrotron-based X-ray scattering measurements. Second, we followed in-situ the transition toward MAPI phase by annealing using a combination of gas-phase TEM and temperature-resolved XRD.

Références :

[1]        A. A. Petrov et al. Journal of Physical Chemistry C, vol. 121, no. 38, pp. 20739–20743, Sep. 2017, doi: 10.1021/acs.jpcc.7b08468.
[2]        C. Sidhoum et al. Chemistry of Materials, vol. 35, no. 19, pp. 7943–7956, Oct. 2023, doi: 10.1021/acs.chemmater.3c01167.

Jules Allègre (INES)

Posted on by mkepenek

Title | Impact of self-assembled monolayers as hole transport layers in a mixed MA free Pb/Sn perovskite solar cell

Date | January 8, 2024 @ 09:30

Abstract | Mixed lead (Pb) – tin (Sn) perovskite (PK) solar cells increase rapidly in efficiency lately notably because of improvement of bulk defects and interface passivation. Those devices commonly use poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) as hole transport layer due to its ease of process and good energy level alignment but it also impedes the thermal stability of the device [1]. Here, we use self-assembled monolayer (SAM), [2-(9H-Carbazol-9-yl)ethyl]phosphonic acid (2-PACz) and methylphosphonic acid (MPA) to replace PEDOT:PSS layer. Devices with SAM instead of PEDOT:PSS show poor performances which is opposite to Kapil et al. results obtained with mixed methylammonium (MA) based Pb-Sn perovskite [2]. By using photoluminescence (PL) and ultraviolet photoelectron spectroscopy (UPS), we show that this behaviour is due to a potential barrier created at the interface SAM/MA free PK. But, SAM layers also show less interface non radiative recombination which highlight our interest for those layers. Those results identify 2PACz and MPA effectiveness limits in mixed MA free Pb-Sn perovskite solar cells and give insight for other SAM tests.

[1] R. Prasanna et al., Nature Energy 4, 939 (2019), https://doi.org/10.1038/s41560-019-0471-6.

[2] G. Kapil et al., ACS Energy Lett. 7, 966 (2022), https://doi.org/10.1021/acsenergylett.1c02718

JPH 2024

Posted on by mkepenek

The Journées Pérovskites Halogénées (JPH) is a major meeting for the national and European community around halide perovskites.

Specifically designed to meet the needs of the research community, from PhDs to researchers to industrial and institutional players, this event offers tutorials, prestigious lectures held by renowned speakers, as well as oral presentations and posters showcasing the latest laboratory results.

Since 2015, each edition brings together around a hundred experts in the field for a few days. The topics addressed are diverse, covering aspects such as the synthesis of new perovskite materials, their transformation into thin films, their fundamental electrical and optical properties, their integration into various devices (including sensors and solar cells) and the associated physical aspects.

After Cachan, Rennes, Angers, Grenoble, Limoges, Palaiseau, Lyon and Biarritz, the JPH arrive at Aix-les-Bains, on the shores of Lac du Bourget, also known as the Riviera of the Alps, from April 3 to 5, 2024.

You will find below, a list of the invited speakers.

Session 1 – Synthesis and fundamental properties
Carole Diederichs École Normale Supérieure-Paris France
Michal Baranovski University of Science and Technology -Wroclaw Poland
Session 2 – Material characterization, simulation & modelisation
Maria Antonietta Loi University of Groningen Netherlands
Felix Lang University of Potsdam Germany
Session 3 – Optoelectronic devices
Diego Di Girolamo ENEL / 3SUN – Catane Italy
Salvador Eslava Imperial College – London UK
Tutorials
Muriel Boutemy Institut Léonard De-Vinci France
Adrien Rivalland Comissariat à l’Énergie Atomique et Énergie Alternative France

 

You can now register and submit abstracts using the following link:

https://www.ines-solaire.org/agenda/journees-perovskites-halogenees-3-4-5-avril-2024-aix-les-bains-france/

Alexandre Abhervé (MOLTECH-Anjou)

Posted on by mkepenek

Title | Chiral Halide Perovskite Materials for Optoelectronic and Spintronic Devices

Date | December 4, 2023

Abstract | Chiral Halide Perovskites (HPs) bring new perspectives for chiroptical applications, such as circularly polarized luminescence (CPL), and spintronic applications. For example, the emergent field of chiro-spintronics proposes to use chiral molecules as a substitute for ferromagnetic materials thanks to the spin-specific interaction between electrons and chiral molecules, a phenomenon called CISS, “Chirality-Induced Spin Selectivity”. By combining the optoelectronic properties of HP networks with chirality transfer from inserted organic cations, I aim to reveal the potential of chiral HP materials for CPL and chiro-spintronics. After an introduction about the objectives of my CNRS project, I will present the main results obtained during the first year. Starting from small chiral alkyl cations, we obtained a large series of 2D and 1D lead-halide networks. The 2D HPs have been investigated for the CISS effect, which allowed us to highlight the impact of crystal symmetry in the spin polarization ability of this class of materials [1]. With the 1D lead-halide networks, we could reveal the intrinsic and extrinsic chiroptical responses by circular dichroism measurements on thin films (unpublished results).

[1] A. Abhervé, N. Mercier, A. Kumar, T. K. Das, J. Even, C. Katan, M. Kepenekian, Adv. Mater. 2023, in press. https://doi.org/10.1002/adma.202305784