http://pubs.acs.org/journal/aelccp
Celebrating 10 Years of Perovskite Photovoltaics his April marks 10 years since the first paper by Kojima, Miyasaka, and co-workers was published, exploring photoelectrochemical properties of metalhalide perovskites in a liquid-junction solar cell.1 The next breakthrough in the field came when solid-state devices with efficiencies in the range of 10% were reported in 2012.2−4 The early developments in the field can be followed through published reviews [Perovskite Solar Cells: The Birth of a New Era in Photovoltaics (10.1021/acsenergylett.7b00137)] and virtual issues [Lead-Free Perovskite Solar Cells. ACS Energy Lett., 2017, 2, 904−905 (10.1021/acsenergylett.7b00246) and Hybrid Perovskites for Multijunction Tandem Solar Cells and Solar Fuels. A Virtual Issue. ACS Energy Lett., 2018, 3, 28−29 (10.1021/acsenergylett.7b01134)]. The unprecedented popularity of the field, seen through the exponential rise of published papers as well as citations during the last 10-year period, shows the major impact of the discipline in the broader scientific world (Figure 1). More than
ACS Energy Lett. 2019.4:853-854. Downloaded from pubs.acs.org by 193.93.192.197 on 04/12/19. For personal use only.
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Figure 2. Filippo De Angelis, Henry Snaith, and Annamaria Petrozza at 2016 PSCO (left to right). Reprinted from 10.1021/ acsenergylett.7b00979.
leading scientists offering some interesting aspects that motivated them to pursue perovskite research are presented separately in this issue (10.1021/acsenergylett.9b00512). The first reports of ABX3 compounds (with A = monovalent cation, M = Pb, and X = halide) date back the end of the 19th century;5 the structural determination of metal-halide perovskites (MHPs) dates to 1958;6 and the synthesis and characterization of methylammonium lead iodide date to 1978.7 The discovery of the applicative potential of MHPs in optoelectronic devices is due to the work by Mitzi and coworkers, who in the early 1990s explored a large variety of metal-halide perovskites with various dimensionality for application in transistors and light-emitting diodes.8 It was only in 2009, more than a century after their initial discovery, that MHPs were applied as absorbers in conventional dye-sensitized solar cell (DSC) architectures based on mesoporous TiO2 and an I−/I3− liquid electrolyte.1 The
Figure 1. Rise of perovskite research as viewed through the published papers and their citation impact during 2009−2018 (Source: Web of Science, Clarivate Analytics March 3, 2019).
10 000 papers published during 2009−2018 have garnered nearly 400 000 citations. Of these, 1069 papers have been identified as Highly Cited papers by Web of Science, having garnered more than 260 000 citations. ACS Energy Letters continues to be a major player in publishing in this field, with wide-ranging topics that include fundamental properties of 0D, 2D, and 3D materials; excitedstate and electronic properties; ion migration; defect chemistry; theoretical modeling; solar cells; and light-emitting devices. This Editorial briefly jogs down memory lane and tracks the path traveled during the last 10 years (Figure 2). The current status of the field and potential future opportunities are also discussed. To celebrate the mark of 10 years of perovskite photovoltaics, a collection of quotes from © 2019 American Chemical Society
Published: April 12, 2019 853
DOI: 10.1021/acsenergylett.9b00500 ACS Energy Lett. 2019, 4, 853−854
Editorial
Cite This: ACS Energy Lett. 2019, 4, 853−854
ACS Energy Letters
Editorial
reported devices, based on “quantum dots” of methylammonium lead iodide and bromide (MAPbI3 and MAPbBr3, respectively) exhibited a modest ∼3.8% maximum efficiency and were substantially unstable. A significant dependence of the open-circuit voltage on the band gap of the perovskite absorber was observed, however, with MAPbI3- and MAPbBr3based devices exhibiting VOC of 0.96 and 0.61 V, respectively, suggestive of an uncommon type of dye-sensitized solar cell. DSCs based on MAPbI3 reached 6.5% in 2011 with the work by Park and co-workers, who devised an improved perovskite deposition strategy.9 Miyasaka’s paper1 initially received little attention, gathering only 31 citations from its publication to the end of 2012. Being recognized as the forefather of the perovskite revolution, this paper now has more than 6000 citations (Web of Science). 2012 was the golden year for perovskite research with the sequential publication of Kanatzidis’ and co-workers paper on the use of CsSnI3 as a hole transporter and absorber in solidstate DSCs in May;2 followed in August by the work by Park, Grätzel, and co-workers on all-solid-state DSCs, employing TiO2/MAPbI3 and Spiro-OMe-TAD as hole-transporting material;3 and in October by Snaith, Miyasaka, and coworkers’ paper employing an insulating mesoporous Al2O3 scaffold for “MAPbI2Cl” deposition in a solid-state “mesosuperstructure” solar cell architecture with Spiro-OMe-TAD as hole-transporting material.4 Unexpectedly, the Al2O3-based device outperformed the TiO2-based one and demonstrated the photovoltaic ability of the perovskite without the need of an electron transport layer. The following years witnessed an unprecedented rise in photovoltaic efficiency,10 leading now to a certified 23.7% record efficiency recently reported by scientists at the Chinese Academy of Sciences (https://www. nrel.gov/pv/cell-efficiency.html) The success of MHPs is not limited to solar cells; these materials have been employed in a variety of optoelectronic devices with groundbreaking results, including LEDs, sensors, and even artificial synapses. MHPs, which can be easily and conveniently deposited from solution, combine a unique set of optoelectronic properties, which are hard to find even in hightemperature processed/high-purity semiconductors. Perhaps the most surprising of such properties is the MHP resilience to crystal imperfections and grain boundaries, unavoidable in polycrystalline thin films, which allows collection of charge carriers with minimal losses. The obvious MHPs drawbacks are the low material stability and the presence of lead. While stability issues may be overcome by, for example, alloying of different A-cations and halides or by interfacing 2D and 3D perovskites, the presence of lead seems (as of today) almost unavoidable. Replacing lead with tin, which seems a viable solution to obtaining fairly efficient lead-free perovskite solar cells, leads to additional instability issues related to Sn(II) oxidation to Sn(IV) and as such may take a long time to become effective. Whereas perovskite research continues to address fundamental materials issues and photoinduced processes, industrial research is taking steps toward market solutions. All-perovskite solar façades and perovskite/silicon tandem solar cells, including the bifacial tandem with an equivalent conversion efficiency of 30.2% recently reported by researchers at the Energy Research Centre of the Netherlands,11 seem to be potential areas in which perovskites could have an immediate market impact.
The last 10 years have witnessed an unprecedented revolution in thin-film photovoltaics with the entry of metal halide perovskites. From an editorial perspective, we see a bright future for fundamentally advancing the basic knowledge as well as engineering more efficient and stable devices in the next 10 years. There also lies further scope in searching for new types of devices based on innovative MHP compositions that combine electronic, spin−orbital, and ionic properties. ACS Energy Letters looks forward to publishing the most exciting developments in MHPs, offering a fast publication route and dedicated Editorial team to ensure a high scientific quality and immediate visibility of published work.
Filippo De Angelis, Senior Editor
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Universita degli Studi di Perugia Dipartimento di Chimica Biologia e Biotecnologie, Perugia, Italy 06123
AUTHOR INFORMATION
ORCID
Filippo De Angelis: 0000-0003-3833-1975 Notes
Views expressed in this editorial are those of the author and not necessarily the views of the ACS.
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REFERENCES
(1) Kojima, A.; Teshima, K.; Shirai, Y.; Miyasaka, T. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 2009, 131, 6050−6051. (2) Chung, I.; Lee, B.; He, J.; Chang, R. P. H.; Kanatzidis, M. G. Allsolid-state dye-sensitized solar cells with high efficiency. Nature 2012, 485, 486−489. (3) Kim, H.-S.; Lee, C.-R.; Im, J.-H.; Lee, K.-B.; Moehl, T.; Marchioro, A.; Moon, S.-J.; Humphry-Baker, R.; Yum, J.-H.; Moser, J. E.; Grätzel, M.; Park, N.-G. Lead Iodide Perovskite Sensitized AllSolid-State Submicron Thin Film Mesoscopic Solar Cell with Efficiency Exceeding 9%. Sci. Rep. 2012, 2, 591. (4) Lee, M. M.; Teuscher, J.; Miyasaka, T.; Murakami, T. N.; Snaith, H. J. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 2012, 338, 643−647. (5) Wells, H. L. Ü ber die Cäsium-und Kalium-Bleihalogenide. Z. Anorg. Chem. 1893, 3, 195. (6) Møller, C. Crystal Structure and Photoconductivity of Caesium Plumbohalides. Nature 1958, 182, 1436. (7) Weber, D. CH3NH3PbX3, ein Pb(II)-system mit kubisher perowskitstruktur. Z. Naturforsch., B: J. Chem. Sci. 1978, 33, 1443− 1445. (8) Mitzi, D. B.; Wang, S.; Feild, C. A.; Chess, C. A.; Guloy, A. M. Conducting Layered Organic−Inorganic Halides Containing ⟨110⟩Oriented Perovskite Sheets. Science 1995, 267, 1473−1476. (9) Im, J.-H.; Lee, C.-R.; Lee, J.-W.; Park, S.-W.; Park, N.-G. 6.5% efficient perovskite quantum-dot-sensitized solar cell. Nanoscale 2011, 3, 4088−4093. (10) De Angelis, F.; Kamat, P. V. A Conversation with Michael Grätzel. ACS Energy Lett. 2017, 2, 1674−1676. (11) Bellini, E. Netherlands’ ECN achieves 30.2% efficiency for bifacial tandem cell based on perovskite. PV Magazine, https://www. pv-magazine.com/2019/03/04/netherlands-ecn-achieves-30-2efficiency-for-bifacial-tandem-cell-based-on-perovskite/.
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DOI: 10.1021/acsenergylett.9b00500 ACS Energy Lett. 2019, 4, 853−854
