FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W3039580051> ?p ?o ?g. }

• W3039580051 endingPage "1593" @default.
• W3039580051 startingPage "1575" @default.
• W3039580051 abstract "•A new strategy to enhance the device performance while simplifying the device structure•New design rules to rationally screen multi-functional interface layer•Long-term stability without encapsulation upon exposure to moisture, heat, and light•Correlations between molecular orientation or passivation and device performance Perovskite solar cells (PSCs) have attracted tremendous attention because of the high efficiencies, ease of fabrication, and low cost of production. However, further enhancement of device efficiency has been a bottleneck, and the instability of the PSCs hampers their commercialization. In this work, we strategically introduce a new multi-functional interface layer that integrates five different functions to improve the device efficiency and long-term stability of PSCs, pushing forward the development of the PSC technology. A significantly improved power conversion efficiency of 21.0% was achieved along with the remarkable stability (up to 1,700 h) without encapsulation under various external stimuli (light, heat, and moisture). These results open new avenues to design advanced interlayers, simplifying the device structure, and enhancing efficiency and stability, that can accelerate the market readiness of perovskite-based optoelectronics. Simultaneously improving device efficiency and stability is the most important issue in perovskite solar cell (PSC) research. Here, we strategically introduce a multi-functional interface layer (MFIL) with integrated roles of: (1) electron transport, (2) moisture barrier, (3) near-infrared photocurrent enhancement, (4) trap passivation, and (5) ion migration suppression to enhance the device performance. The narrow-band-gap non-fullerene acceptor, Y6, was screened out to replace the most commonly used PCBM in the inverted PSCs. A significantly improved power conversion efficiency of 21.0% was achieved, along with a remarkable stability (up to 1,700 h) without encapsulation under various external stimuli (light, heat, and moisture). Furthermore, systematic studies of the molecular orientation or passivation and the charge carrier dynamics at the interface between perovskite and MFIL were presented. These results offer deep insights for designing advanced interlayers and establish the correlations between molecular orientation, interface molecular bonding, trap state density, non-radiation recombination, and the device performance. Simultaneously improving device efficiency and stability is the most important issue in perovskite solar cell (PSC) research. Here, we strategically introduce a multi-functional interface layer (MFIL) with integrated roles of: (1) electron transport, (2) moisture barrier, (3) near-infrared photocurrent enhancement, (4) trap passivation, and (5) ion migration suppression to enhance the device performance. The narrow-band-gap non-fullerene acceptor, Y6, was screened out to replace the most commonly used PCBM in the inverted PSCs. A significantly improved power conversion efficiency of 21.0% was achieved, along with a remarkable stability (up to 1,700 h) without encapsulation under various external stimuli (light, heat, and moisture). Furthermore, systematic studies of the molecular orientation or passivation and the charge carrier dynamics at the interface between perovskite and MFIL were presented. These results offer deep insights for designing advanced interlayers and establish the correlations between molecular orientation, interface molecular bonding, trap state density, non-radiation recombination, and the device performance. Organic-inorganic hybrid perovskite thin-film solar cells have emerged as an efficient solar-energy technology with excellent power conversion efficiencies (PCEs), ease of fabrication, and low production cost, proving to be a game changer in photovoltaics.1Li Z. Klein T.R. Kim D.H. Yang M. Berry J.J. van Hest M.F.A.M. Zhu K. Scalable fabrication of perovskite solar cells.Nat. Rev. Mater. 2018; 3: 18017Crossref Scopus (395) Google Scholar, 2Wang R. Xue J. Wang K.L. Wang Z.K. Luo Y. Fenning D. Xu G. Nuryyeva S. Huang T. Zhao Y. et al.Constructive molecular configurations for surface-defect passivation of perovskite photovoltaics.Science. 2019; 366: 1509-1513Crossref PubMed Scopus (238) Google Scholar, 3Zheng Y. Su R. Xu Z. Luo D. Dong H. Jiao B. Wu Z. Gong Q. Zhu R. Perovskite solar cell towards lower toxicity: A theoretical study of physical lead reduction strategy.Science Bulletin. 2019; 64: 1255-1261Crossref Scopus (30) Google Scholar Significant effort has been devoted to optimizing device efficiencies4NREL Best research-cell efficiency chart.https://www.nrel.gov/pv/cell-efficiency.htmlGoogle Scholar and to further understand inherent material properties.5Jena A.K. Kulkarni A. Miyasaka T. Halide perovskite photovoltaics: background, status, and future prospects.Chem. Rev. 2019; 119: 3036-3103Crossref PubMed Scopus (761) Google Scholar Some strategies, including crystallization and morphology optimization of perovskite thin films,6Hu Q. Zhao L. Wu J. Gao K. Luo D. Jiang Y. Zhang Z. Zhu C. Schaible E. Hexemer A. et al.In situ dynamic observations of perovskite crystallisation and microstructure evolution intermediated from [PbI6]4− cage nanoparticles.Nat. Commun. 2017; 8: 15688Crossref PubMed Scopus (117) Google Scholar composition-tunable alloying7Wang K. Subhani W.S. Wang Y. Zuo X. Wang H. Duan L. Liu S.F. Metal cations in efficient perovskite solar cells: progress and perspective.Adv. Mater. 2019; 31e1902037Crossref PubMed Scopus (24) Google Scholar for increasing light absorption, and interface engineering8Deng W. Liang X. Kubiak P.S. Cameron P.J. Molecular interlayers in hybrid perovskite solar cells.Adv. Energy Mater. 2018; 8: 1701544Crossref Scopus (52) Google Scholar within the device structure, have been adapted to enhance the PCEs. Despite these efforts to improve device performance, the lifespan of perovskite solar cells (PSCs) is still too short for practical use.9Wang L. Zhou H. Hu J. Huang B. Sun M. Dong B. Zheng G. Huang Y. Chen Y. Li L. et al.A Eu3+-Eu2+ ion redox shuttle imparts operational durability to Pb-I perovskite solar cells.Science. 2019; 363: 265-270Crossref PubMed Scopus (369) Google Scholar,10Tu Y. Xu G. Yang X. Zhang Y. Li Z. Su R. Luo D. Yang W. Miao Y. Cai R. et al.Mixed-cation perovskite solar cells in space.Sci. China Phys. Mech. Astron. 2019; 62: 974221Crossref Scopus (68) Google Scholar Thus, simultaneously improving device efficiency and stability has become the most important issue at present. The inherent “soft” crystal lattice of perovskite solids is one of the key reasons for poor stability, which makes PSCs vulnerable to aging stresses, such as UV-light, moisture, electric field, and thermal annealing. In addition, structural defects in the bulk and on the surfaces of perovskite polycrystalline thin films, ion migration, hygroscopic additives, and the thermal instability of charge transporting layers, are also contributors to PSCs’ performance deterioration.11Meng L. You J. Yang Y. Addressing the stability issue of perovskite solar cells for commercial applications.Nat. Commun. 2018; 9: 5265Crossref PubMed Scopus (224) Google Scholar Various approaches have been applied to improve the perovskite quality and critical interfaces, and PSCs can now survive under environment stresses from hours to months. For instance, to selectively oxidize Pb0 and reduce I0 defects, Europium ion pairs, Eu3+-Eu2+, can be added as the “redox shuttle,” increasing device efficiency and longevity.9Wang L. Zhou H. Hu J. Huang B. Sun M. Dong B. Zheng G. Huang Y. Chen Y. Li L. et al.A Eu3+-Eu2+ ion redox shuttle imparts operational durability to Pb-I perovskite solar cells.Science. 2019; 363: 265-270Crossref PubMed Scopus (369) Google Scholar Ionic liquid additives12Bai S. Da P. Li C. Wang Z. Yuan Z. Fu F. Kawecki M. Liu X. Sakai N. Wang J.T.-W. et al.Planar perovskite solar cells with long-term stability using ionic liquid additives.Nature. 2019; 571: 245-250Crossref PubMed Scopus (454) Google Scholar have also been shown to improve the surface energetic alignment and suppress ion migration, resulting in longer-lasting output. Moreover, a double-layer perovskite structure with in situ reaction of hydrophobic chemicals (n-hexyl trimethyl ammonium bromide13Jung E.H. Jeon N.J. Park E.Y. Moon C.S. Shin T.J. Yang T.Y. Noh J.H. Seo J. Efficient, stable and scalable perovskite solar cells using poly(3-hexylthiophene).Nature. 2019; 567: 511-515Crossref PubMed Scopus (1017) Google Scholar or lead sulfate14Yang S. Chen S. Mosconi E. Fang Y. Xiao X. Wang C. Zhou Y. Yu Z. Zhao J. Gao Y. et al.Stabilizing halide perovskite surfaces for solar cell operation with wide-bandgap lead oxysalts.Science. 2019; 365: 473-478Crossref PubMed Scopus (310) Google Scholar) can passivate the perovskite surface, yielding higher open-circuit voltages (Voc) and enhanced moisture resistance. In addition to the optimization of the perovskite active layer, significant contributions have also been made to reduce surface disorder, improve charge extraction, and enhance the chemical stability of the electron or hole transporting layer (ETL or HTL) toward the goal of maximizing device stability. Compared with the regular n-i-p structure, the p-i-n (aka inverted) structure shows great potential to realize long-term operational stability, due to the use of stable metal oxide semiconductors or undoped conjugated polymers or small molecules as the interface layers.15Luo D. Yang W. Wang Z. Sadhanala A. Hu Q. Su R. Shivanna R. Trindade G.F. Watts J.F. Xu Z. et al.Enhanced photovoltage for inverted planar heterojunction perovskite solar cells.Science. 2018; 360: 1442-1446Crossref PubMed Scopus (705) Google Scholar, 16Liu T. Chen K. Hu Q. Zhu R. Gong Q. Inverted perovskite solar cells: progresses and perspectives.Adv. Energy Mater. 2016; 6: 1600457Crossref Scopus (253) Google Scholar, 17Chen H. Wei Q. Saidaminov M.I. Wang F. Johnston A. Hou Y. Peng Z. Xu K. Zhou W. Liu Z. et al.Efficient and stable inverted perovskite solar cells incorporating secondary amines.Adv. Mater. 2019; 31e1903559Crossref PubMed Scopus (64) Google Scholar Having a robust ETL in p-i-n PSCs is also needed for implementing a perovskite as the front cell in perovskite:silicon or all-perovskite tandem solar cells.18Tong J. Song Z. Kim D.H. Chen X. Chen C. Palmstrom A.F. Ndione P.F. Reese M.O. Dunfield S.P. Reid O.G. et al.Carrier lifetimes of >1 μs in Sn-Pb perovskites enable efficient all-perovskite tandem solar cells.Science. 2019; 364: 475-479Crossref PubMed Scopus (348) Google Scholar,19Jošt M. Köhnen E. Morales-Vilches A.B. Lipovšek B. Jäger K. Macco B. Al-Ashouri A. Krč J. Korte L. Rech B. et al.Textured interfaces in monolithic perovskite/silicon tandem solar cells: advanced light management for improved efficiency and energy yield.Energy Environ. Sci. 2018; 11: 3511-3523Crossref Google Scholar Furthermore, inverted PSCs are also compatible with plastic substrates that require low-temperature fabrication for flexible devices.20Yang D. Yang R. Priya S. Liu S.F. Recent advances in flexible perovskite solar cells: fabrication and applications.Angew. Chem. Int. Ed. Engl. 2019; 58: 4466-4483Crossref PubMed Scopus (124) Google Scholar Unfortunately, p-i-n PSCs have not kept pace with n-i-p PSCs in device efficiencies due to lower short current densities (Jsc)21Chen W. Sun H. Hu Q. Djurišić A.B. Russell T.P. Guo X. He Z. High short-circuit current density via integrating the perovskite and ternary organic bulk heterojunction.ACS Energy Lett. 2019; 4: 2535-2536Crossref Scopus (21) Google Scholar and/or larger Voc losses induced by non-radiative recombination.22Luo D. Su R. Zhang W. Gong Q. Zhu R. Minimizing non-radiative recombination losses in perovskite solar cells.Nat. Rev. Mater. 2020; 5: 44-60Crossref Scopus (241) Google Scholar On top of poorer performance, inverted PSCs also usually exhibit modest stability against water and light, mainly due to the use of fullerenes with low-crystallinity and large aggregation as the ETL.23Akbulatov A.F. Frolova L.A. Griffin M.P. Gearba I.R. Dolocan A. Vanden Bout D.A. Tsarev S. Katz E.A. Shestakov A.F. Stevenson K.J. Trosin P.A. Effect of electron-transport material on light-induced degradation of inverted planar junction perovskite solar cells.Adv. Energy Mater. 2017; 7: 1700476Crossref Scopus (63) Google Scholar Therefore, new strategies to realize both high efficiencies and high stabilities for inverted PSCs are urgently needed. Here, we introduce a multi-functional interface layer (MFIL) approach to combine the roles of (1) electron transport, (2) moisture barrier, (3) near-infrared (NIR) photocurrent enhancement, (4) trap passivation, and (5) ion migration suppression in inverted PSCs, and to simultaneously improve the device efficiency and long-term stability of PSCs. Compared with the fullerenes, the non-fullerenes can be easily chemically tuned to obtain superior physical properties, such as light absorption, energy level, and charge generation.24Yuan J. Zhang Y. Zhou L. Zhang G. Yip H.-L. Lau T.-K. Lu X. Zhu C. Peng H. Johnson P.A. et al.Single-junction organic solar cell with over 15% efficiency using fused-ring acceptor with electron-deficient core.Joule. 2019; 3: 1140-1151Abstract Full Text Full Text PDF Scopus (1871) Google Scholar, 25Yao H. Cui Y. Yu R. Gao B. Zhang H. Hou J. Design, synthesis, and photovoltaic characterization of a small molecular acceptor with an ultra-narrow band gap.Angew. Chem. Int. Ed. Engl. 2017; 56: 3045-3049Crossref PubMed Scopus (550) Google Scholar, 26Yan C. Liu T. Chen Y. Ma R. Tang H. Li G. Li T. Xiao Y. Yang T. Lu X. et al.ITC-2Cl: a versatile middle-bandgap nonfullerene acceptor for high-efficiency panchromatic ternary organic solar cells.Sol. RRL. 2020; 4: 1900377Crossref Scopus (13) Google Scholar, 27Chen Y. Liu T. Hu H. Ma T. Lai J.Y.L. Zhang J. Ade H. Yan H. Modulation of end groups for low-bandgap nonfullerene acceptors enabling high-performance organic solar cells.Adv. Energy Mater. 2018; 8: 1801203Crossref Scopus (77) Google Scholar Thus, non-fullerenes have the great potential to realize these functions of MFILs. A new small-band-gap non-fullerene acceptor (NFA), Y6 (as shown in Figure 1), a popular BT-core-based fused-unit dithienothiophen[3,2-b]-pyrrolobenzothiadiazole (TPBT) derivative, was screened from a series of narrow-band-gap acceptor materials to replace the commonly used PCBM without any additive or donor materials in the solid thin film. The molecular orientation, the electronic states of local structures, and the surface morphology of the Y6 layer were systematically investigated for the full device stack. The high mobility and suitable energy levels of Y6 matched the perovskite active layer quite well,24Yuan J. Zhang Y. Zhou L. Zhang G. Yip H.-L. Lau T.-K. Lu X. Zhu C. Peng H. Johnson P.A. et al.Single-junction organic solar cell with over 15% efficiency using fused-ring acceptor with electron-deficient core.Joule. 2019; 3: 1140-1151Abstract Full Text Full Text PDF Scopus (1871) Google Scholar and the narrow optical band gap extended the photoresponse cutoff from ∼775 to ∼940 nm, resulting in an improved integrated Jsc. Interfacial bonding interactions between the perovskite and Y6 were further analyzed using advanced surface spectroscopies: X-ray photoelectron spectroscopy (XPS) and synchrotron-based X-ray total fluorescence yield (TFY). We find that chemical complexing of electron-rich C–S–C, C=O, C≡N, and C–F functional groups in Y6 with the empty orbitals in Pb2+ or other electron traps at the perovskite interface, led to reductions in trap state density and non-radiative recombination, enhanced electron extraction, and suppressed ion migration in operation, resulting in the enhanced Voc, fill factor (FF) and a champion PCE of 21.0%. We also used steady-state and time-resolved photoluminescence (TRPL) spectra, steady-state microwave conductivity (SSMC) measurements, and ultrafast transient absorption spectroscopy (TAS) to elucidate the underlying charge carrier dynamics. Furthermore, in combination with the hydrophobic properties of Y6, which impedes water penetration, the surface chemical stability, intrinsic photo-stability at standard AM1.5G conditions, ambient stability with humidity of 60%–65%, and thermal stability at 85°C were all increased significantly for Y6-based devices in contrast to PCBM-based devices. This MFIL strategy opens up new pathways for ETL design and optimization for inverted PSCs, since it concomitantly enhances both device efficiency and stability, thus more broadly accelerating the market readiness of perovskite-based optoelectronics. Figure 1A shows the device architecture of the inverted planar heterojunction PSCs studied in this work. A cross-sectional scanning transmission electron microscopy (STEM) image is shown in Figure S1. Poly(triarylamine) (PTAA) is used as the HTL, and the tri-cation CsFAMA (FA, formamidinium; MA, methylammonium) perovskite with a band gap of ∼1.6 eV was fabricated as photoactive layer (see details in Experimental Procedures). We observed a uniform, compact morphology of the perovskite layer from the SEM image (Figure S1B). As a control, PCBM was used as the ETL to contrast a series of narrow-band-gap NFAs24Yuan J. Zhang Y. Zhou L. Zhang G. Yip H.-L. Lau T.-K. Lu X. Zhu C. Peng H. Johnson P.A. et al.Single-junction organic solar cell with over 15% efficiency using fused-ring acceptor with electron-deficient core.Joule. 2019; 3: 1140-1151Abstract Full Text Full Text PDF Scopus (1871) Google Scholar, 25Yao H. Cui Y. Yu R. Gao B. Zhang H. Hou J. Design, synthesis, and photovoltaic characterization of a small molecular acceptor with an ultra-narrow band gap.Angew. Chem. Int. Ed. Engl. 2017; 56: 3045-3049Crossref PubMed Scopus (550) Google Scholar, 26Yan C. Liu T. Chen Y. Ma R. Tang H. Li G. Li T. Xiao Y. Yang T. Lu X. et al.ITC-2Cl: a versatile middle-bandgap nonfullerene acceptor for high-efficiency panchromatic ternary organic solar cells.Sol. RRL. 2020; 4: 1900377Crossref Scopus (13) Google Scholar, 27Chen Y. Liu T. Hu H. Ma T. Lai J.Y.L. Zhang J. Ade H. Yan H. Modulation of end groups for low-bandgap nonfullerene acceptors enabling high-performance organic solar cells.Adv. Energy Mater. 2018; 8: 1801203Crossref Scopus (77) Google Scholar, 28Liu T. Luo Z. Chen Y. Yang T. Xiao Y. Zhang G. Ma R. Lu X. Zhan C. Zhang M. et al.A nonfullerene acceptor with a 1000 nm absorption edge enables ternary organic solar cells with improved optical and morphological properties and efficiencies over 15%.Energy Environ. Sci. 2019; 12: 2529-2536Crossref Google Scholar (Y6, IEICO-4F and IOIC-2Cl). The UV-visible (UV-vis) absorption spectra of tri-cation CsFAMA perovskite and the ETLs are shown in Figure 1B. All of the NFAs studied here extend the light-absorption from the visible (∼775 nm) to the NIR region (∼940 nm). However, when we fabricated full devices to screen these ETLs, only the Y6-based device gave a higher efficiency (20.5%, Figure 1D) than the PCBM control, a result of a Voc of 1.11 V, FF of 0.78, and Jsc of 23.7 mA·cm−2, with contribution from the extended NIR photoresponse as shown in the external quantum efficiency (EQE) spectrum (Figure 1E). In contrast, the IOIC-2Cl and IEICO-4F devices both decreased the relative device performance with PCEs of 13.6% (Voc = 1.03 V, FF = 0.54, Jsc = 24.5 mA·cm−2) and 10.8% (Voc = 1.04 V, FF = 0.46, Jsc = 22.5 mA·cm−2), respectively. The very poor FF and Voc results were likely caused by mismatched energy level alignments and high interfacial charge recombination as shown in Figure 1C. Thus, we propose the first guidelines to screen effective narrow-band-gap NFAs as candidates for a MFIL: (1) complementary light harvesting, (2) a favorable surface energetic alignment (deeper lowest unoccupied molecular orbital [LUMO] and highest occupied molecular orbital [HOMO] energy than perovskite), (3) suitable charge mobility, and (4) electron donating functional groups to passivate the perovskite surface. Of the three NFAs here, Y6 is the only one that meets the criteria set for MFILs, though we also expect that inorganic semiconductor materials, such as NIR-absorbing quantum dots, could do so as well, as long as the energetic and functional group requirements are also fulfilled. In organic semiconductors, exciton dissociation and charge transport are sensitive to molecular order. We found that the crystallization and aggregation of Y6 can be precisely controlled in different solvent environments. The π-π stacking of Y6 films for efficient charge extraction was investigated by grazing incident X-ray diffraction (GIXD), as shown in Figure 2A. Three typical solvents with different boiling points, chloroform (CF), toluene (Tol), and chlorobenzene (CB), were used to process the Y6 films. The CF-processed Y6 (Y6-CF) film has a dominant π-π stacking diffraction peak at q ∼ 1.77 Å−1 in the out of plane (OOP) direction with a d-spacing of 3.55 Å and a crystalline coherence length (CCL) of 21.36 Å (calculated by Scherrer equation29Lilliu S. Agostinelli T. Pires E. Hampton M. Nelson J. Macdonald J.E. Dynamics of crystallization and disorder during annealing of P3HT/PCBM bulk heterojunctions.Macromolecules. 2011; 44: 2725-2734Crossref Scopus (164) Google Scholar and the full width at half maximum intensity was calculated from Gaussian fitting), forming a typical face-on orientation. The (110) peak and (11-1) peaks, simulated from single crystal structure with the unique 2D packing with polymer-like conjugated backbone (as shown in Figure S2), in the in-plane (IP) direction are located at q ∼ 0.29 and q ∼ 0.42 Å−1 with d-spacing of 21.65 and 14.95 Å, respectively. The GIXD scattering results and the related single crystal simulation indicate that the banana-like Y6 molecules grow or stack normal to substrate interface resulting in more efficient charge transfer by π-π stacking.30Zhu L. Zhang M. Zhou G. Hao T. Xu J. Wang J. Qiu C. Prine N. Ali J. Feng W. et al.Efficient organic solar cell with 16.88% efficiency enabled by refined acceptor crystallization and morphology with improved charge transfer and transport properties.Adv. Energy Mater. 2020; 10: 1904234Crossref Scopus (148) Google Scholar The diffraction profiles from the Tol-processed Y6 (Y6-Tol) and CB-processed Y6 (Y6-CB) films are quite similar, but the π-π stacking reflection is much weaker and less oriented in comparison to Y6-CF, suggesting reduced crystallinity and a more random orientation. The enhanced scattering at q ∼ 1.20 Å−1 indicates an increased amorphous content in Y6-CB and Y6-Tol. The corresponding integrated profiles in the IP and OOP directions are shown in Figure 2B. The detailed CCL and areas of the characteristic peaks are summarized in Figure 2D (OOP) and Figure S3 (IP). The Y6-CF has a greater peak area and CCL for the π-π stacking and (11-1) reflections, in comparison with those of Y6-CB and Y6-Tol, which have close d-spacings. In addition, the peak areas of π-π stacking reflections in OOP and IP are summarized in Figure 2E. The peak area ratio of the π-π stacking reflection in OOP to that in IP for Y6-CF is ∼3.5, while the Y6-CB and Y6-Tol values are close to 1.0, indicating that the π-π stacking for the Y6-CF film is significantly more oriented normal to the substrate, reducing the surface disorder at the perovskite and Y6 interface and enhancing efficient electron extraction and transport from the perovskite active layers, as shown in Figure 2C. The morphology and electronic properties of the surface of Y6 films were further investigated by the Kelvin probe force microscope (KPFM). Figure S4 shows the surface topography of the perovskite/Y6 films. The root mean square (RMS) roughness values are 5.49 (Y6-CF), 5.95 (Y6-Tol), and 8.28 nm (Y6-CB), which could correspond to effects of different solvent vapor pressures during the film drying process. The solvent-rich films (with high-boiling point solvent) have insufficient time to heal surface roughness caused by Marangoni instabilities, reducing the film roughness.31Strawhecker K.E. Kumar S.K. Douglas J.F. Karim A. The critical role of solvent evaporation on the roughness of spin-cast polymer films.Macromolecules. 2001; 34: 4669-4672Crossref Scopus (191) Google Scholar The redshift of the longest-wavelength light absorption peak (∼840 nm) in the UV-vis spectra, as seen in Figure S5, suggest the enhanced molecular packing with larger aggregations in Y6-Tol and Y6-CB films, this is consistent with the recent report in Y6-based organic solar cells.30Zhu L. Zhang M. Zhou G. Hao T. Xu J. Wang J. Qiu C. Prine N. Ali J. Feng W. et al.Efficient organic solar cell with 16.88% efficiency enabled by refined acceptor crystallization and morphology with improved charge transfer and transport properties.Adv. Energy Mater. 2020; 10: 1904234Crossref Scopus (148) Google Scholar The contact potential difference (CPD) images of perovskite/Y6 films are shown in Figure 2F. In agreement with the surface topography, the variation of the CPD value for Y6-CF is 0.016 V and Y6-Tol is 0.022 V whereas Y6-CB is 0.024 V. The similarity of the CPD values suggests that different molecular packing or surface morphology in Y6 films has little influence on the surface potential. In summary, compared with Y6-CB and Y6-Tol, the Y6-CF film shows the dominant face-on orientation with the highest degree of crystallinity (GIXD results), as well as the smoothest surface topography and surface potential distribution (KPFM). Therefore, the best device performance with Y6-CF was expected. Inverted PSC devices incorporating Y6 layers with different molecular orientations (based on casting solvent) were fabricated and characterized. The device parameters measured under a standard AM1.5G solar illumination (100 mW·cm−2) are summarized in Table S1. All the Y6-based devices have a very similar Jsc and Voc. However, the Y6-CF device had the highest FF of 0.78 and the highest PCE of 20.5%, while the Y6-Tol and Y6-CB had lower FF of 0.70 and 0.68, resulting in PCEs of 17.9% and 17.7%, respectively. A sharp decrease in the FFs of Y6-Tol- and Y6-CB-based devices is ascribed to the increased series resistance (Rs) and decreased shunt resistance (Rsh) (shown in Table S1), which could be caused by increased surface roughness and less efficient interfacial charge transport. These results further argue that the face-on orientation and π-π stacking in the Y6-CF film is responsible for more efficient extraction and transport of electrons from the perovskite layer. Moreover, the device performance also confirms that the photoexcited excitons from the Y6-CF layer can be dissociated at the interface and contributes to a higher Jsc. This is further evidenced by the enhanced EQE in the NIR region of Y6-CF devices (Figure S6). The Y6-CF devices were also optimized by varying the film thickness using different solution concentrations (Figure S7), a 9.5 mg/mL solution giving a thickness of 46.3 nm (Table S2) yielded the best performance. When a very thin layer of C60 (20 nm) was added onto the Y6-CF film to further enhance the charge extraction,32Golubev T. Liu D. Lunt R. Duxbury P. Understanding the impact of C60 at the interface of perovskite solar cells via drift-diffusion modeling.AIP Adv. 2019; 9035026Crossref Scopus (9) Google Scholar both the FF and Voc increased, yielding a champion PCE of 21.0%. As a result, this approach was used for all devices. The device performance with Y6 and traditional PCBM was further examined. Compared with those of the PCBM-based device, the Voc (from 1.10 to 1.12 V) and FF (from 0.77 to 0.79) of the Y6-based device are slightly enhanced while the Jsc increased significantly from 22.64 to 23.68 mA·cm−2, leading to the enhancement in the PCE from 19.2% to 21.0%, as shown in Figure 3A. The EQE spectrum of the Y6 device (Figure 3B) showed an extended photoreponse in the NIR region (∼940 nm), demonstrating the synergistic functions of Y6, both as a photoactive layer and a charge transport medium. The integrated current densities from the EQEs are 21.86 mA·cm−2 (PCBM) and 22.85 mA·cm−2 (Y6), which are consistent with the enhanced Jsc from the J-V curves. It should be noted that the devices have negligible hysteresis under a range of different scanning conditions. In addition, the stabilized power output (SPO) at maximum power point (MPP) were also tracked to confirm the efficiency reliability. As shown in Figure S8, the Y6-based devices had a stabilized efficiency of 20.9%, while the PCBM-based device had an output of 19.1%. In addition, the Y6-based devices also showed excellent reproducibility with small standard deviations, as shown in Table S3 based on 20 devices. To explore the origins for the enhanced device performance of Y6-based devices, the carrier transport properties were determined. Both steady-state and TRPL spectra were measured (Figures 3C and 3D). The PL peaks of perovskite (PVSK) with Y6 and PVSK with PCBM films are both located at ∼767 nm. Compared with that of the pure perovskite sample, the PL intensities of both the PVSK with PCBM and PVSK with Y6 samples decreased markedly, indicating a comparable charge extraction for Y6 in comparison to PCBM. The charge recombination kinetics were measured by TRPL spectra, which could be described with a double exponential decay function, suggesting two decay processes, a non-radiative recombination process and a radiative recombination process. The charge-carrier lifetimes are shown in Table S4. The average lifetime for the pure perovskite is 602.0 ns, but dropped to 30.1 ns for the PVSK with PCBM sample, due to charge-carrier transfer from PVSK to PCBM, giving rise to the TRPL intensity quenching. The further decrease in the TRPL intensity and shorter lifetime of 14.5 ns for PVSK with Y6 suggests a faster charge transfer" @default.
• W3039580051 created "2020-07-10" @default.
• W3039580051 creator A5002344232 @default.
• W3039580051 creator A5008613026 @default.
• W3039580051 creator A5017541508 @default.
• W3039580051 creator A5018073672 @default.
• W3039580051 creator A5018298417 @default.
• W3039580051 creator A5029685348 @default.
• W3039580051 creator A5030339000 @default.
• W3039580051 creator A5033794555 @default.
• W3039580051 creator A5034930424 @default.
• W3039580051 creator A5037411813 @default.
• W3039580051 creator A5048085561 @default.
• W3039580051 creator A5049001639 @default.
• W3039580051 creator A5059620765 @default.
• W3039580051 creator A5060470951 @default.
• W3039580051 creator A5060691871 @default.
• W3039580051 creator A5080856942 @default.
• W3039580051 creator A5084540011 @default.
• W3039580051 date "2020-07-01" @default.
• W3039580051 modified "2023-10-12" @default.
• W3039580051 title "Improving Efficiency and Stability of Perovskite Solar Cells Enabled by A Near-Infrared-Absorbing Moisture Barrier" @default.
• W3039580051 cites W1968286323 @default.
• W3039580051 cites W1968737010 @default.
• W3039580051 cites W2007395042 @default.
• W3039580051 cites W2055247124 @default.
• W3039580051 cites W2068625397 @default.
• W3039580051 cites W2083222334 @default.
• W3039580051 cites W2315557091 @default.
• W3039580051 cites W2334452713 @default.
• W3039580051 cites W2395956896 @default.
• W3039580051 cites W2547891055 @default.
• W3039580051 cites W2560455873 @default.
• W3039580051 cites W2585473308 @default.
• W3039580051 cites W2592268197 @default.
• W3039580051 cites W2607378409 @default.
• W3039580051 cites W2623152317 @default.
• W3039580051 cites W2662873333 @default.
• W3039580051 cites W2705902370 @default.
• W3039580051 cites W2728532059 @default.
• W3039580051 cites W2754387220 @default.
• W3039580051 cites W2757891104 @default.
• W3039580051 cites W2765853045 @default.
• W3039580051 cites W2790131079 @default.
• W3039580051 cites W2790131787 @default.
• W3039580051 cites W2811284615 @default.
• W3039580051 cites W2885547713 @default.
• W3039580051 cites W2897045528 @default.
• W3039580051 cites W2898568184 @default.
• W3039580051 cites W2902119819 @default.
• W3039580051 cites W2909990379 @default.
• W3039580051 cites W2910856350 @default.
• W3039580051 cites W2911789225 @default.
• W3039580051 cites W2914354396 @default.
• W3039580051 cites W2917106215 @default.
• W3039580051 cites W2919043374 @default.
• W3039580051 cites W2921709259 @default.
• W3039580051 cites W2923019151 @default.
• W3039580051 cites W2937886105 @default.
• W3039580051 cites W2938079366 @default.
• W3039580051 cites W2940017382 @default.
• W3039580051 cites W2944370267 @default.
• W3039580051 cites W2948324038 @default.
• W3039580051 cites W2952824761 @default.
• W3039580051 cites W2962424236 @default.
• W3039580051 cites W2966424648 @default.
• W3039580051 cites W2974351421 @default.
• W3039580051 cites W2975760103 @default.
• W3039580051 cites W2981728652 @default.
• W3039580051 cites W2989642950 @default.
• W3039580051 cites W2994551035 @default.
• W3039580051 cites W2994622674 @default.
• W3039580051 cites W2999691245 @default.
• W3039580051 cites W3011388529 @default.
• W3039580051 cites W3022390477 @default.
• W3039580051 doi "https://doi.org/10.1016/j.joule.2020.06.007" @default.
• W3039580051 hasPublicationYear "2020" @default.
• W3039580051 type Work @default.
• W3039580051 sameAs 3039580051 @default.
• W3039580051 citedByCount "77" @default.
• W3039580051 countsByYear W30395800512020 @default.
• W3039580051 countsByYear W30395800512021 @default.
• W3039580051 countsByYear W30395800512022 @default.
• W3039580051 countsByYear W30395800512023 @default.
• W3039580051 crossrefType "journal-article" @default.
• W3039580051 hasAuthorship W3039580051A5002344232 @default.
• W3039580051 hasAuthorship W3039580051A5008613026 @default.
• W3039580051 hasAuthorship W3039580051A5017541508 @default.
• W3039580051 hasAuthorship W3039580051A5018073672 @default.
• W3039580051 hasAuthorship W3039580051A5018298417 @default.
• W3039580051 hasAuthorship W3039580051A5029685348 @default.
• W3039580051 hasAuthorship W3039580051A5030339000 @default.
• W3039580051 hasAuthorship W3039580051A5033794555 @default.
• W3039580051 hasAuthorship W3039580051A5034930424 @default.
• W3039580051 hasAuthorship W3039580051A5037411813 @default.
• W3039580051 hasAuthorship W3039580051A5048085561 @default.
• W3039580051 hasAuthorship W3039580051A5049001639 @default.
• W3039580051 hasAuthorship W3039580051A5059620765 @default.

• next