23 Sep 12:43
by Diego Di Girolamo,
Fabio Matteocci,
Felix Utama Kosasih,
Ganna Chistiakova,
Weiwei Zuo,
Giorgio Divitini,
Lars Korte,
Caterina Ducati,
Aldo Di Carlo,
Danilo Dini,
Antonio Abate
Hysteresis in the dark, attributable to bias induced degradation of the p‐type interface, is investigated and eliminated in NiO‐based inverted perovskite solar cells. Enhanced stability to forward bias is obtained with the introduction of a low‐temperature hybrid magnesium‐based interlayer.
Abstract
In perovskite solar cells (PSCs), the interfaces are a weak link with respect to degradation. Electrochemical reactivity of the perovskite's halides has been reported for both molecular and polymeric hole selective layers (HSLs), and here it is shown that also NiO brings about this decomposition mechanism. Employing NiO as an HSL in p–i–n PSCs with power conversion efficiency (PCE) of 16.8%, noncapacitive hysteresis is found in the dark, which is attributable to the bias‐induced degradation of perovskite/NiO interface. The possibility of electrochemically decoupling NiO from the perovskite via the introduction of a buffer layer is explored. Employing a hybrid magnesium‐organic interlayer, the noncapacitive hysteresis is entirely suppressed and the device's electrical stability is improved. At the same time, the PCE is improved up to 18% thanks to reduced interfacial charge recombination, which enables more efficient hole collection resulting in higher V
oc and FF.
23 Sep 12:43
by Jun Xi,
Chengcheng Piao,
Junseop Byeon,
Jungjin Yoon,
Zhaoxin Wu,
Mansoo Choi
A rational core–shell design of open air low temperature in situ processable CsPbI3 quasi‐nanocrystals is proposed. A bifunctional ligand 4‐fluorophenethylammonium iodide and new compound H2PbI4 increase crystal stability, charge extraction, and assist divalent ion doping, respectively. The best p‐i‐n solar cell with 13.4% efficiency can retain 72% beyond 500 h in ambient air without encapsulation.
Abstract
As a promising alternative, inorganic perovskite nanocrystals allow reinforced stability of photovoltaic device. Unfortunately, directly assembling these nanocrystals into film is uncontrollable. Instead, in situ assembling technology under low temperature in open air is attractive but limited due to the tendency of nonperovskite transition. The adverse shell ligands and unstable core lattices are known as the fundamental problems. In order to address this issue, here proposed is a rational core–shell design: 1) with respect to ligands, a new one, 4‐fluorophenethylammonium iodide, is used to enhance bonding force and charge coupling between ligands and nanocrystals; 2) with respect to lattices, a novel compound H2PbI4 is employed to assist divalent ion (Mn2+) doping into perovskite lattices. By low temperature in situ processing CsPbI3 quasi‐nanocrystal film, the highest power conversion efficiency of 13.4% for p‐i‐n solar cells is achieved, which retains 92% after 500 h in ambient air. The current study underlines the significance of rational hierarchical design of inorganic perovskite nanocrystals, especially for low temperature in situ processable electronic devices.
23 Sep 12:41
by Boer Tan,
Sonia R. Raga,
Anthony S. R. Chesman,
Sebastian O. Fürer,
Fei Zheng,
David P. McMeekin,
Liangcong Jiang,
Wenxin Mao,
Xiongfeng Lin,
Xiaoming Wen,
Jianfeng Lu,
Yi‐Bing Cheng,
Udo Bach
Spiro‐OMeTAD(TFSI)2 is successfully employed in the fabrication of highly efficient n–i–p perovskite solar cells as a p‐dopant in the absence of lithium bis(trifluoromethane)sulfonimide (LiTFSI) and air exposure. With this approach, the proportion of [spiro‐OMeTAD]+ is precisely controlled, and the spiro‐OMeTAD(TFSI)2‐doped devices show a remarkably improved long‐term stability and well‐retained hole‐transporting material (HTM) morphology after aging for 300 h.
Abstract
To date, the most efficient perovskite solar cells (PSCs) employ an n–i–p device architecture that uses a 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) hole‐transporting material (HTM), which achieves optimum conductivity with the addition of lithium bis(trifluoromethane)sulfonimide (LiTFSI) and air exposure. However, this additive along with its oxidation process leads to poor reproducibility and is detrimental to stability. Herein, a dicationic salt spiro‐OMeTAD(TFSI)2, is employed as an effective p‐dopant to achieve power conversion efficiencies of 19.3% and 18.3% (apertures of 0.16 and 1.00 cm2) with excellent reproducibility in the absence of LiTFSI and air exposure. As far as it is known, these are the highest‐performing n–i–p PSCs without LiTFSI or air exposure. Comprehensive analysis demonstrates that precise control of the proportion of [spiro‐OMeTAD]+ directly provides high conductivity in HTM films with low series resistance, fast hole extraction, and lower interfacial charge recombination. Moreover, the spiro‐OMeTAD(TFSI)2‐doped devices show improved stability, benefitting from well‐retained HTM morphology without forming aggregates or voids when tested under an ambient atmosphere. A facile approach is presented to fabricate highly efficient PSCs by replacing LiTFSI with spiro‐OMeTAD(TFSI)2. Furthermore, this study provides an insight into the relationship between device performance and the HTM doping level.
23 Sep 12:37
by Haoran Liu,
Zhi‐Xi Liu,
Shuxu Wang,
Jiang Huang,
Huanxin Ju,
Qi Chen,
Junsheng Yu,
Hongzheng Chen,
Chang‐Zhi Li
The introduction of funtional molecular self‐assembled monolayers (SAMs) atop of zinc oxide (ZnO) effectively optimizes the energetic and heterojunction properties of the organic–metal oxide interface to improve the performance and photostability of nonfullerene polymer solar cells.
Abstract
Charge events across organic–metal oxide heterointerfaces routinely occur in organic electronics, yet strongly influence their overall performance and stability. They become even more complicated and challenging for the heterojunction conditions in polymer solar cells (PSCs), especially when nonfullerene acceptors with varied energetics are employed. In this work, an effective interfacial strategy that utilizes novel small molecule self‐assembled monolayers (SAMs) is developed to improve the electronic and electric, as well as chemical properties of organic–zinc oxide (ZnO) interfaces for nonfullerene PSCs. It is revealed that the tailored SAMs with well‐controlled energy levels and molecular dipoles can effectively optimize the energetic barrier and work function (WF) of heterointerface for optimal electron extraction. In addition, the introduction of SAMs atop of ZnO facilitates not only acceptor segregation near the n‐contact interface, but also passivation of the photocatalytic activities for ZnO, to improve overall performance and photo stability of the derived nonfullerene PSCs. Overall, the methodology and structure–property relationship revealed herein would be beneficial for a wide range of hybrid electronics.
23 Sep 12:31
by Sheng Fu,
Xiaodong Li,
Li Wan,
Yulei Wu,
Wenxiao Zhang,
Yueming Wang,
Qinye Bao,
Junfeng Fang
Stable and efficient perovskite solar cells (PSCs) are achieved via introducing PbPyA2 as an additive. Benefiting from the strong interaction, incorporating PbPyA2 can lower the defects, suppress ion migration and component volatilization of perovskite, resulting in great improvements in heat and humidity tolerance. More importantly, the resulting PSC maintains 93% of initial efficiency after maximum power point tracking for 540 h.
Abstract
Stability has become the main obstacle for the commercialization of perovskite solar cells (PSCs) despite the impressive power conversion efficiency (PCE). Poor crystallization and ion migration of perovskite are the major origins of its degradation under working condition. Here, high‐performance PSCs incorporated with pyridine‐2‐carboxylic lead salt (PbPyA2) are fabricated. The pyridine and carboxyl groups on PbPyA2 can not only control crystallization but also passivate grain boundaries (GBs), which result in the high‐quality perovskite film with larger grains and fewer defects. In addition, the strong interaction among the hydrophobic PbPyA2 molecules and perovskite GBs acts as barriers to ion migration and component volatilization when exposed to external stresses. Consequently, superior optoelectronic perovskite films with improved thermal and moisture stability are obtained. The resulting device shows a champion efficiency of 19.96% with negligible hysteresis. Furthermore, thermal (90 °C) and moisture (RH 40–60%) stability are improved threefold, maintaining 80% of initial efficiency after aging for 480 h. More importantly, the doped device exhibits extraordinary improvement of operational stability and remains 93% of initial efficiency under maximum power point (MPP) tracking for 540 h.
21 Sep 08:13
J. Mater. Chem. A, 2019, 7,19811-19819
DOI: 10.1039/C9TA02852H, Paper
Shrabani Panigrahi, Santanu Jana, Tomás Calmeiro, Daniela Nunes, Jonas Deuermeier, Rodrigo Martins, Elvira Fortunato
Increased interfacial carrier generation with effective carrier separation through the plasmonic effect enhanced the surface potential inside plasmon-based solar cells.
The content of this RSS Feed (c) The Royal Society of Chemistry
21 Sep 08:12
J. Mater. Chem. A, 2019, 7,19423-19429
DOI: 10.1039/C9TA06009J, Paper
Xiaomei Lian, Jiehuan Chen, Yingzhu Zhang, Minchao Qin, Thomas Rieks Andersen, Jun Ling, Gang Wu, Xinhui Lu, Deren Yang, Hongzheng Chen
GA+ with solvation effect assisted high-quality 2D perovskite film with thickness over 500 nm reached a PCE of 16.26%.
The content of this RSS Feed (c) The Royal Society of Chemistry
07 Sep 03:12
by Daniel Cruz†¶, Jose Garcia Cerrillo‡¶, Baris Kumru†, Ning Li‡?, Jose Dario Perea‡#, Bernhard V. K. J. Schmidt†, Iver Lauermann?, Christoph J. Brabec‡§, and Markus Antonietti*†
Journal of the American Chemical Society
DOI: 10.1021/jacs.9b03639
awn, 北极光 and 4 others like this
03 Sep 04:46
by Lijian Zuo,
Xueliang Shi,
Weifei Fu,
Alex K.‐Y. Jen
A semitransparent photovoltaic (ST‐PV) with a tandem architecture and selective absorption in invisible regions is designed. By developing highly efficient active layers that selective absorb in the UV and near‐infrared regions and designing an appropriate interconnecting layer and transparent electrode, the resulting tandem ST‐PV device exhibits light utilization efficiency of 5.7% with averaged visible transmittance (AVT) of 52.9% and power conversion efficiency up to 10.7%.
Abstract
Semitransparent (ST) photovoltaics (PVs) with selective absorption in the UV or/and near‐infrared (NIR) range(s) and reduced energy losses, are critical for high‐efficiency solar‐window applications. Here, a high‐performance tandem ST‐PV with selected absorption in the desirable regions of the solar spectrum is demonstrated. An ultralarge‐bandgap perovskite film (FAPbBr2.43Cl0.57, E
g ≈ 2.36 eV) is first developed to fulfil efficient selective absorption in the UV region. After optimization, the corresponding ST single junction (SJ) PV exhibits an averaged transmittance (AVT) of ≈68% and an efficiency of ≈7.5%. By sequentially reducing the visible absorbing component in a low‐bandgap organic bulk‐heterojunction layer, an ST‐PV with selective absorption in the NIR is achieved with a power conversion efficiency (PCE) of 5.9% and a high AVT of 62%. The energy loss associated with the SJ ST‐PVs is further reduced with a tandem architecture, which affords a high PCE of 10.7%, an AVT of 52.91%, and a light utilization efficiency up to 5.66%. These results represent the best balance of AVT and PCE among all ST‐PVs reported so far, and this design should pave the road for solar windows of high performance.
03 Sep 04:45
by Jishan Shi,
Yerun Gao,
Xiang Gao,
Yun Zhang,
Junjie Zhang,
Xin Jing,
Ming Shao
A remarkable high efficiency of 17.34% is achieved for low‐dimensional Ruddlesden–Popper perovskite (RPP) solar cells (n ≤ 5) by using a fluorinated phenylethalammonium (4‐fluoro‐phenethylammonium (4FPEA)) organic cation. These fluorinated devices also show the better humidity and thermal stability as compared to nonfluorinated phenylethlammonium (PEA) devices. These findings provide a feasible approach for simultaneously improving the efficiency and stability of low‐dimensional RPP solar cells.
Abstract
Low‐dimensional Ruddlesden–Popper perovskites (RPPs) exhibit excellent stability in comparison with 3D perovskites; however, the relatively low power conversion efficiency (PCE) limits their future application. In this work, a new fluorine‐substituted phenylethlammonium (PEA) cation is developed as a spacer to fabricate quasi‐2D (4FPEA)2(MA)4Pb5I16 (n = 5) perovskite solar cells. The champion device exhibits a remarkable PCE of 17.3% with a J
sc of 19.00 mA cm−2, a V
oc of 1.16 V, and a fill factor (FF) of 79%, which are among the best results for low‐dimensional RPP solar cells (n ≤ 5). The enhanced device performance can be attributed as follows: first, the strong dipole field induced by the 4‐fluoro‐phenethylammonium (4FPEA) organic spacer facilitates charge dissociation. Second, fluorinated RPP crystals preferentially grow along the vertical direction, and form a phase distribution with the increasing n number from bottom to the top surface, resulting in efficient charge transport. Third, 4FPEA‐based RPP films exhibit higher film crystallinity, enlarged grain size, and reduced trap‐state density. Lastly, the unsealed fluorinated RPP devices demonstrate superior humidity and thermal stability. Therefore, the fluorination of the long‐chain organic cations provides a feasible approach for simultaneously improving the efficiency and stability of low‐dimensional RPP solar cells.
03 Sep 04:44
by Jiangzhao Chen,
Xing Zhao,
Seul‐Gi Kim,
Nam‐Gyu Park
A multifunctional chemical linker of 4‐imidazoleacetic acid hydrochloride (ImAcHCl) between SnO2 and a perovskite layer improves the average power conversion efficiency from 18.60% to 20.22% due to the upward shift of band position, reduced nonradiative recombination, and improved carrier lifetime. In addition, interfacial engineering improves thermal and moisture stability.
Abstract
Chemical interaction at a heterojunction interface induced by an appropriate chemical linker is of crucial importance for high efficiency, hysteresis‐less, and stable perovskite solar cells (PSCs). Effective interface engineering in PSCs is reported via a multifunctional chemical linker of 4‐imidazoleacetic acid hydrochloride (ImAcHCl) that can provide a chemical bridge between SnO2 and perovskite through an ester bond with SnO2 via esterification reaction and an electrostatic interaction with perovskite via imidazolium cation in ImAcHCl and iodide anion in perovskite. In addition, the chloride anion in ImAcHCl plays a role in the improvement of crystallinity of perovskite film crystallinity. The introduction of ImAcHCl onto SnO2 realigns the positions of the conduction and valence bands upwards, reduces nonradiative recombination, and improves carrier life time. As a consequence, average power conversion efficiency (PCE) is increased from 18.60% ± 0.50% to 20.22% ± 0.34% before and after surface modification, respectively, which mainly results from an enhanced voltage from 1.084 ± 0.012 V to 1.143 ± 0.009 V. The best PCE of 21% is achieved by 0.1 mg mL−1 ImAcHCl treatment, along with negligible hysteresis. Moreover, an unencapsulated device with ImAcHCl‐modified SnO2 shows much better thermal and moisture stability than unmodified SnO2.
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