PEROVSKITE MODULE
We fabricated the first perovskite-based monolithic series-type module showing very promising results in terms of the power conversion efficiency, the reproducibility of the fabrication process and long-term stability. To achieve these results, important innovative procedures were implemented in order to realize an efficient up-scaling process including:
- a customised formulation of TiO2 paste to realize a uniform thin titania scaffold by Screen Printing technique
- a proper cleaning procedure of the CH3NH3PbI3-xClx on the interconnection area between single cells to realize a patterned perovskite deposition
- a c-TiO2 patterned deposition
Furthermore, two different HTMs were used, i.e. the Spiro-OMeTAD and the P3HT polymer both reaching a PCE equal to 5.1%. The P3HT was utilized as cost-effective alternative material also to test the reproducibility of the fabrication process. These fabrication processes were here used for the first time to define a reproducible fabrication procedure applicable to large area. To achieve better performance in terms of PCE and long-term stability, future developments will concentrate on the study of efficient sealants, the optimisation of the perovskite deposition and the cleaning procedure of the interconnection area between neighbouring cells.
F. Matteocci, S. Razza, F. Di Giacomo, S. Casaluci, G. Mincuzzi, T. M. Brown, A. D'Epifanio, S. Licoccia and A. Di Carlo
"Solid-state solar modules based on mesoscopic organometal halide perovskite: a route towards the up-scaling process"
DOI: 10.1039/C3CP55313B
PHOTOELECTROCHEMICAL AND SPECTROPHOTOMETRIC STUDIES ON DYE-SENSITIZED SOLAR CELLS (DSCS) AND STABLE MODULES (DSCMS) BASED ON NATURAL APOCAROTENOIDS PIGMENTS
ABSTRACT
We present a study on dye-sensitized solar cells (DSCs) and we fabricate dye-sensitized solar modules (DSCMs) based on natural apocarotenoids extracted from the achiote's seeds (annatto). Use of less polar solvent such as diethyl ether improves the bixin concentration in the annatto extract which, was employed as sensitizer in the devices. We measure IPCE max (∼33%) and estimate ϕinj≥0.438 for annatto. By accurate and progressive optimization of both TiO2 multilayer photoanode and of electrolyte composition an efficiency (η) around 1.6%, is achieved, with an improvement of about ∼742% compare to the best performance for annatto extract, so far reported. DSCM shows stability which overcomes 1000 h (shelf-life test), under 1 sun, and produces a battery capacity of ∼46.8 Ah, the equivalent to ∼15 type AAA standard battery, in a similar time period. Although annatto based DSCMs are still below the efficiency requirements for practical applications for large scale industry, our encouraging results, testify the potentiality of this pigment in the production of non-toxic, cheap, long term stable and environmentally friendly vegetable based solar devices, as alternatives to batteries for small electronic goods market.
Giuseppe Calogero, Jessica Barichello, Ilaria Citro, Paolo Mariani, Luigi Vesce, Antonino Bartolotta, Aldo Di Carlo, Gaetano Di Marco
Dyes and Pigments 155 (2018) 75-83
doi: 10.1016/j.dyepig.2018.03.021
FULLY-SPRAYED FLEXIBLE POLYMER SOLAR CELLS WITH A CELLULOSE-GRAPHENE ELECTRODE
Light, flexible and low-cost organic solar cells made entirely by spray and with an innovative cellulose and graphene-based electrode!
The work, in collaboration with the Smart Materials group of the ISTITUTO ITALIANO DI TECNOLOGIA has been published on the important magazine "Materials Today Energy".
ABSTRACT
Organic photovoltaic (OPV) technology provides energy where conventional photovoltaics are difficult to implement. The rise of efficiency due to the introduction of new polymers and the definition of strategies for the scale-up push OPV devices towards large-scale manufacturing. Here, spray coating has been employed as an easy and versatile scalable technique to deposit all the layers of flexible polymer solar cells starting from PET/ITO/Ag/ITO substrates. A foldable nanocomposite based on cellulose and sprayed graphene nanoplatelets has been applied as top electrode through lamination. The overall fabrication process has been conducted in air by using commercial materials. A significant power conversion efficiency higher than 3% has been achieved and the high quality of the lamination process has been demonstrated by bending and adhesion tests. Such photovoltaic devices are the first fully-sprayed prototypes on plastic substrate and the novel structure has also been effective for devices with active area up to 0.75 cm2.
Luca La Notte, Pietro Cataldi, Luca Ceseracciu, Ilker S. Bayer, Athanassia Athanassiou, Sergio Marras, Enrica Villari, Francesca Brunetti, Andrea Reale
Materials Today Energy
January 2018
ON THE IMPORTANCE OF FERROELECTRIC DOMAINS FOR THE PERFORMANCE OF PEROVSKITE SOLAR CELLS
The effect of ferroelectric polarization patterns in MAPbI3 on JV characteristics has been analyzed. We discuss models for the polarization orientation pattern and magnitude of the ferroelectric domains. Simulations performed on real patterns show that the presence of ordered ferroelectric domains, even with a weak characteristic polarization magnitude enhances the power conversion efficiencies and are mandatory to reproduce the experimental J-V characteristics.
ABSTRACT
This work analyzes in detail the effect of ferroelectric polarization patterns in methylammonium lead iodide (MAPbI3) thin-films on the J-V characteristics of the corresponding solar cells. The simulations are based on a finite-element discretization of the drift-diffusion equations and take into account the polarization pattern experimentally derived from piezoresponse force micrographs. Based on the knowledge of the crystalline structure, symmetry considerations and electrical simulations, we discuss models for the polarization orientation pattern and magnitude of the ferroelectric domains. We conclude that the in-plane polarization vectors have 45° orientation towards the domain walls and form herring-bone structures. The presence of ordered ferroelectric domains, even with a weak characteristic polarization magnitude enhances the power conversion efficiencies and are mandatory to reproduce the experimental J-V characteristics.
Daniele Rossi, Alessandro Pecchia, Matthias Auf der Maur, Tobias Leonhard, Holger Röhm, Michael J. Hoffmann, Alexander Colsmann, Aldo Di Carlo
DOI: 10.1016/j.nanoen.2018.02.049
https://www.sciencedirect.com/science/article/pii/S2211285518301174
HIGHLY EFFICIENT PEROVSKITE SOLAR CELLS FOR LIGHT HARVESTING UNDER INDOOR ILLUMINATION VIA SOLUTION PROCESSED SNO2/MGO COMPOSITE ELECTRON TRANSPORT LAYERS
ABSTRACT
We present new architectures in CH3NH3PbI3 based planar perovskite solar cells incorporating solution processed SnO2/MgO composite electron transport layers that show the highest power outputs ever reported under typical 200–400 lx indoor illumination conditions. When measured under white OSRAM LED lamp (200, 400 lx), the maximum power density values were 20.2 µW/cm2 (estimated PCE = 25.0%) at 200 lx and 41.6 µW/cm2 (PCE = 26.9%) at 400 lx which correspond to a ∼ 20% increment compared to solar cells with a SnO2 layer only. The thin MgO overlayer leads to more uniform films, reduces interfacial carrier recombination, and leads to better stability. All layers of the cells, except for the two electrodes, are solution processed at low temperatures, thus low cost processing. Furthermore, ambient indoor conditions represent a milder environment compared to stringent outdoor conditions for a technology that is still looking for a commercial outlet also due to stability concerns. The unparalleled performance here demonstrated, paves the way for perovskite solar cells to contribute strongly to the powering of the indoor electronics of the future (e.g. smart autonomous indoor wireless sensor networks, internet of things etc).
Janardan Dagar, Sergio Castro-Hermosa, Giulia Lucarelli, Franco Cacialli, Thomas M. Brown
DOI: 10.1016/j.nanoen.2018.04.027
https://www.sciencedirect.com/science/article/pii/S221128551830257X
FACILE SYNTHESIS OF A SNO2@RGO NANOHYBRID AND OPTIMIZATION OF ITS METHANE-SENSING PARAMETERS
ABSTRACT
Stannic oxide nanoparticles and various compositions of SnO2@rGO (reduced graphene oxide) nanohybrids were synthesized by a facile hydrothermal method and utilized as chemiresistive methane gas sensors. To characterize the synthesized nanohybrids, BET (Brunauer-Emmett-Teller), XRD, FESEM, TEM, FTIR, and Raman techniques were used. Sensing elements were tested using a U-tube flow chamber with temperature control. To obtain the best sensor performance, i.e., the highest signal and the fastest response and recovery times, the sensing element composition, operating temperature, and gas flow rate were optimized. The highest response (change in resistance) of 47.6% for 1000 ± 5 ppm methane was obtained with the SnO2@rGO1% nanohybrid at 150 °C and a flow rate of 160 sccm; the response and recovery times were 61 s and 5 min, respectively. A sensing mechanism was suggested, based on the experiments.
Shiva Navazani, Ali Shokuhfar, Mostafa Hassanisadi, Mojtaba Askarieh, Aldo Di Carlo, Antonio Agresti
DOI: 10.1016/j.talanta.2018.01.015
https://www.sciencedirect.com/science/article/pii/S0039914018300213
ENHANCED CHARGE SEPARATION EFFICIENCY IN DNA TEMPLATED POLYMER SOLAR CELLS
ABSTRACT
The insertion of a DNA nanolayer into polymer based solar cells, between the electron transport layer (ETL) and the active material, is proposed to improve the charge separation efficiency. Complete bulk heterojunction donor–acceptor solar cells of the layered type glass/electrode (indium tin oxide)/ETL/P3HT:PC70BM/hole transport layer/electrode (Ag) are investigated using femtosecond transient absorption spectroscopy both in the NIR and the UV–vis regions of the spectrum. The transient spectral changes indicate that when the DNA is deposited on the ZnO nanoparticles (ZnO‐NPs) it can imprint a different long range order on the poly(3‐hexylthiophene) (P3HT) polymer with respect to the non‐ZnO‐NPs/DNA containing cells. This leads to a larger delocalization of the initially formed exciton and its faster quenching which is attributed to more efficient exciton dissociation. Finally, the temporal response of the NIR absorption shows that the DNA promotes more efficient production of charge transfer states and free polarons in the P3HT cation indicating that the increased exciton dissociation correlates with increased charge separation.
Francesco Toschi, Daniele Catone, Patrick O'Keeffe, Alessandra Paladini, Stefano Turchini, Janardan Dagar, Thomas M. Brown
DOI: 10.1002/adfm.201707126
https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201707126
AGING EFFECTS IN INTERFACE-ENGINEERED PEROVSKITE SOLAR CELLS WITH 2D NANOMATERIALS: A DEPTH PROFILE ANALYSIS
ABSTRACT
The stability of perovskite solar cells (PSCs) is a major factor limiting the market breakthrough of this technology. To understand the aging effects in PSCs is mandatory to rationally design implemented architectures and materials combining a viable deposition process, efficiency and stability. Despite of this evidence, only few experimental works succeeded in the direct quantitative characterization of aging effects in PSCs. In this work, we apply state-of-the-art X-ray photoelectron spectroscopy (XPS) depth profile analysis and time-of-flight secondary ion mass spectrometry (ToF-SIMS) 3D imaging to investigate the light-induced degradation of layers and interfaces in reference (Au/Spiro-OMeTAD/CH3NH3PbI3/m-TiO2/cTiO2/FTO) and interface-engineered mesoscopic PSCs in which graphene flakes are added into the mesoscopic TiO2 layer and a solution-processed 2H-MoS2 flakes buffer layer is added at the Spiro-OMeTAD/CH3NH3PbI3interface. Results show that the graphene addition into the mesoscopic TiO2 layer improves the stability of the PSC by reducing the locally-inhomogeneous light-induced back-conversion of the CH3NH3PbI3 layer into PbIx and PbOx species and the consequent release of iodine species, which diffuse across the interfaces and causes the modifications at the gold electrode (Au-I bonding) and the mesoscopic TiO2 (Ti-I bonding) interfaces. Moreover, where the CH3NH3PbI3 layer is preserved the gold diffusion across the entire device structure is strongly reduced even after the aging. The 2H-MoS2 flakes buffer layer allows limiting the localized diffusion of gold and the iodine diffusion in as-prepared PSCs while it is rather ineffective in preventing light-induced aging effects. Overall, thanks to the lower average degradation of the layers and interfaces, interface engineered PSCs could retain ∼60% of their initial PCE after the aging respect to less than ∼25% in the reference cells.
Yan Busby, Antonio Agresti, Sara Pescetelli, Aldo Di Carlo, Celine Noel, Jean-Jacques Pireaux, Laurent Houssiau
DOI: 10.1016/j.mtener.2018.04.005
https://www.sciencedirect.com/science/article/pii/S2468606918300303
LOW TEMPERATURE, SOLUTION-PROCESSED PEROVSKITE SOLAR CELLS AND MODULES WITH AN APERTURE AREA EFFICIENCY OF 11%
ABSTRACT
Planar perovskite solar cells and modules were realized by using low temperature solution-process fabrication procedures. The photovoltaic performance was improved by optimizing a SnO2 electron transport layer and its interface with the perovskite layer. We achieved a power conversion efficiency (PCE) of 17.3% on small area cell (0.09 cm2) with negligible hysteresis and a steady-state PCE equal to 17.4%. Furthermore, shelf life tests showed a relative decrease of only 5% in PCE from its initial value after 1000 h of storage in dark conditions in air (RH 20%). Up-scaling of the technology was implemented entirely in air with fabrication of modules with a high aperture ratio of 91%. The modules delivered a maximum PCE of 13.1% obtained on an active area of 13.8 cm2and of 11.9% on an aperture area of 15.2 cm2 representing state of art performance for fully low temperature solution processed planar perovskite solar modules.
Emanuele Calabrò, Fabio Matteocci, Alessandro Lorenzo Palma, Luigi Vesce, Babak Taheri, Laura Carlini, Igor Pis, Silvia Nappini, Janardan Dagar, Chiara Battocchio, Thomas M. Brown
DOI: 10.1016/j.solmat.2018.05.001
https://www.sciencedirect.com/science/article/pii/S0927024818302150
MoS2 Quantum Dot/Graphene Hybrids for Advanced Interface Engineering of a CH3 NH3 PbI3 Perovskite Solar Cell with an Efficiency of over 20%
ABSTRACT
Interface engineering of organic–inorganic halide perovskite solar cells (PSCs) plays a pivotal role in achieving high power conversion efficiency (PCE). In fact, the perovskite photoactive layer needs to work synergistically with the other functional components of the cell, such as charge transporting/active buffer layers and electrodes. In this context, graphene and related two-dimensional materials (GRMs) are promising candidates to tune “on demand” the interface properties of PSCs. In this work, we fully exploit the potential of GRMs by controlling the optoelectronic properties of molybdenum disulfide (MoS2) and reduced graphene oxide (RGO) hybrids both as hole transport layer (HTL) and active buffer layer (ABL) in mesoscopic methylammonium lead iodide (CH3NH3PbI3) perovskite (MAPbI3)-based PSCs. We show that zero-dimensional MoS2 quantum dots (MoS2 QDs), derived by liquid phase exfoliated MoS2flakes, provide both hole-extraction and electron-blocking properties. In fact, on one hand, intrinsic n-type doping-induced intraband gap states effectively extract the holes through an electron injection mechanism. On the other hand, quantum confinement effects increase the optical band gap of MoS2 (from 1.4 eV for the flakes to >3.2 eV for QDs), raising the minimum energy of its conduction band (from −4.3 eV for the flakes to −2.2 eV for QDs) above the one of the conduction band of MAPbI3 (between −3.7 and −4 eV) and hindering electron collection. The van der Waals hybridization of MoS2 QDs with functionalized reduced graphene oxide (f-RGO), obtained by chemical silanization-induced linkage between RGO and (3-mercaptopropyl)trimethoxysilane, is effective to homogenize the deposition of HTLs or ABLs onto the perovskite film, since the two-dimensional nature of RGO effectively plugs the pinholes of the MoS2 QD films. Our “graphene interface engineering” (GIE) strategy based on van der Waals MoS2 QD/graphene hybrids enables MAPbI3-based PSCs to achieve a PCE up to 20.12% (average PCE of 18.8%). The possibility to combine quantum and chemical effects into GIE, coupled with the recent success of graphene and GRMs as interfacial layer, represents a promising approach for the development of next-generation PSCs.
Leyla Najafi, Babak Taheri, Beatriz Martín-García, Sebastiano Bellani, Diego Di Girolamo, Antonio Agresti, Reinier Oropesa-Nuñez, Sara Pescetelli, Luigi Vesce, Emanuele Calabrò, Mirko Prato, Antonio E. Del Rio Castillo, Aldo Di Carlo, Francesco Bonaccorso
DOI: 10.1021/acsnano.8b05514
ACS Publications
Publication Date (Web): September 21, 2018
Sustainable Electronics Based on Crop Plant Extracts and Graphene: a “Bioadvantaged” Approach
ABSTRACT
In today's fast‐paced and well‐connected world, consumer electronics are evolving rapidly. As a result, the amount of discarded electronic devices is becoming a major health and environmental concern. The rapid expansion of flexible electronics has the potential to transform consumer electronic devices from rigid phones and tablets to robust wearable devices. This means increased use of plastics in consumer electronics and the potential to generate more persistent plastic waste for the environment. Hence, today, the need for flexible biodegradable electronics is at the forefront of minimizing the mounting pile of global electronic waste. A “bioadvantaged” approach to develop a biodegradable, flexible, and application‐adaptable electronic components based on crop components and graphene is reported. More specifically, by combining zein, a corn‐derived protein, and aleuritic acid, a major monomer of tomato cuticles and sheellac, along with graphene, biocomposite conductors having low electrical resistance (≈10 Ω sq−1) with exceptional mechanical and fatigue resilience are fabricated. Further, a number of high‐performance electronic applications, such as THz electromagnetic shielding, flexible GHz antenna construction, and flexible solar cell electrode, are demonstrated. Excellent performance results are measured from each application comparable to conventional nondegrading counterparts, thus paving the way for the concept of “plant‐e‐tronics” towards sustainability.
Susana Guzman‐Puyol, Luca Ceseracciu, Luca La Notte, Andrea Reale, Jun Ren, Yijie Zhang, Lei Liu, Mario Miscuglio, Patrizia Savi, Simonluca Piazza, Marti Duocastella, Giovanni Perotto, Athanassia Athanassiou, Ilker S. Bayer
DOI: 10.1002/adsu.201800069
05 August 2018
Advanced Sustainable Systems
https://onlinelibrary.wiley.com/doi/full/10.1002/adsu.201800069
Graphene-Engineered Automated Sprayed Mesoscopic Structure for Perovskite Device Scaling-Up
ABSTRACT
One of the most thrilling developments in the photovoltaic field over recent years has been the use of organic–inorganic lead halide perovskite, such as CH3NH3PbI3 (MAPbI3), as a promising new material for low-cost and highly efficient solar cells. Despite the impressive power conversion efficiency (PCE) exceeding 22% demonstrated on lab-scale devices, large-area material deposition procedures and automatized device fabrication protocols are still challenging to achieve high-throughput serial manufacturing of modules and panels. In this work, we demonstrate that spray coating is an effective technique for the production of mesoscopic small- and large-area perovskite solar cells (PSCs). In particular, we report a sprayed graphene-doped mesoporous TiO2 (mTiO2) scaffold for mesoscopic PSCs. By successfully combining the spray coating technique with the insertion of graphene additive into the sprayed mTiO2 scaffold, a uniform film deposition and a significant enhancement of the electron transport/injection at the mTiO2/perovskite electrode is achieved. The use of graphene flakes on the sprayed scaffold boosts the PCE of small-area cells up to 17.5% that corresponds to an increase of more than 15% compared to standard cells. For large-area (1.1 cm2) cells, a PCE up to 14.96% is achieved. Moreover, graphene-doped mTiO2 layer enhances the stability of the PSCs compared to standard devices. The feasibility of PSC fabrication by spray coating deposition of the mesoporous film on large-area 21 × 24 cm2 provides a viable and low-cost route to scale up the manufacturing of low-cost, stable and high-efficiency PSCs.
Babak Taheri, Narges Yaghoobi Nia, Antonio Agresti, Sara Pescetelli, Claudio Ciceroni, Antonio Esaù Del Rio Castillo, Lucio Cinà, Sebastiano Bellani, Francesco Bonaccorso, Aldo Di Carlo
DOI: 10.1088/2053-1583/aad983
25 September 2018
2D Materials
http://iopscience.iop.org/article/10.1088/2053-1583/aad983/meta
A NOVEL CLASS OF DYE-SENSITIZED SOLAR MODULES. GLASS-PLASTIC STRUCTURE FOR MECHANICALLY STABLE DEVICES
ABSTRACT
Owing to its peculiar properties such as transparency, weak angle dependence and improved power conversion efficiency (PCE) at diffused light, DSSCs (Dye Sensitized Solar Cells) are well suited for Building Integrated PhotoVoltaic (BIPV). For large area DSSC devices and modules, one of the main causes of sealing failure is the deformation of the glass substrates due to the sintering process of TiO 2 which occurs significantly at temperatures around 500 °C. The novel class of realized DSSMs (Dye Sensitized Solar Modules) consists in a “Glass/Plastic hybrid” structure with a photo-electrode developed on glass-FTO and a counter-electrode developed on PET-ITO. By adopting this unique solution, it is possible to anneal the photo-electrode at temperatures above 500°C for an optimal TiO 2 sintering and to improve the sturdiness of the devices adapting the flexible counter-electrode on the rigid photo-electrode. Developing the counter-electrode on PET-ITO we halved the thickness and weight of the devices, strengthens the commitment of DSSC technology in BIPV sector where the weights and the volumes occupied by components play a fundamental role in design, fabrication and costs. devices, as alternatives to batteries for small electronic goods market.
Paolo Mariani, Luigi Vesce, Aldo Di Carlo
DOI: 10.1109/RTSI.2018.8548439
2018 IEEE 4th International Forum on Research and Technology for Society and Industry (RTSI) Proceedings
https://ieeexplore.ieee.org/abstract/document/8548439
THERMALLY INDUCED FULLERENE DOMAIN COARSENING PROCESS IN ORGANIC SOLAR CELLS
ABSTRACT
The recent advancements in power conversion efficiency for organic solar cells is still complained by their reliability and stability remaining the main bottlenecks for organic photovoltaics large scale production and commercialization. In this paper, we aim to provide further insights understanding in degradation processes affecting stability in small molecule flat heterojunction (Glass/ITO/MoO₃/ZnPc/C₆₀/BCP/Ag) solar cells through a systematic aging study coupled with optoelectrical characterizations. In particular, the burn-in phenomenon affecting short-circuit current in thermal-stressed samples has been clearly correlated with the C₆₀ domain coarsening process and eventually to the decreased exciton lifetime.
Antonio Agresti, Sara Pescetelli, Yan Busby, Tom Aernouts
DOI: 10.1109/TED.2018.2880760
IEEE Transactions on Electron Devices PP(99):1-11 · November 2018
PRINTED SOLAR CELLS AND ENERGY STORAGE DEVICES ON PAPER SUBSTRATES
ABSTRACT
Paper is a flexible material, commonly used for information storage, writing, packaging, or specialized purposes. It also has strong appeal as a substrate in the field of flexible printed electronics. Many applications, including safety, merchandising, smart labels/packing, and chemical/biomedical sensors, require an energy source to power operation. Here, progress regarding development of photovoltaic and energy storage devices on cellulosic substrates, where one or more of the main material layers are deposited via solution processing or printing, is reviewed. Paper can be used simply as the flexible substrate or, exploiting its porous fiber‐like nature, as an active film by infiltration or copreparation with electronic materials. Solar cells with efficiencies of up to 9% on opaque substrates and 13% on transparent substrates are demonstrated. Recent developments in paper‐based supercapacitors and batteries are also reviewed with maximum achieved capacity of 1350 mF cm−2 and 2000 mAh g−1, respectively. Analyzing the literature, it becomes apparent that more work needs to be carried out in continuing to improve peak performance, but especially stability and the application of printing techniques, even roll‐to‐roll processing, over large areas. Paper is not only environmentally friendly and recyclable, but also thin, flexible, lightweight, biocompatible, and inexpensive.
Francesca Brunetti, Alessandra Operamolla, Sergio Castro‐Hermosa, Giulia Lucarelli, Valerio Manca, Gianluca M. Farinola, Thomas M. Brown
DOI: 10.1002/adfm.201806798
Advanced Functional Materials, 30 January 2019
https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201806798
Università degli Studi di Roma
"Tor Vergata"
