Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Materials Chemistry
Title: Exploiting Noncovalently Conformational Locking as a Design Strategy for High Performance Fused-Ring Electron Acceptor Used in Polymer Solar Cells
Abstract: We have developed a kind of novel fused-ring small molecular acceptor, whose planar conformation can be locked by intramolecular noncovalent interaction. The formation of planar supramolecular fused-ring structure by conformation locking can effectively broaden its absorption spectrum, enhance the electron mobility, and reduce the nonradiative energy loss. Polymer solar cells (PSCs) based on this acceptor afforded a power conversion efficiency (PCE) of 9.6%. In contrast, PSCs based on similar acceptor, which cannot form a flat conformation, only gave a PCE of 2.3%. Such design strategy, which can make the synthesis of small molecular acceptor much easier, will be promising in developing a new acceptor for high efficiency polymer solar cells.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Side-Chain Isomerization on an n-type Organic Semiconductor ITIC Acceptor Makes 11.77% High Efficiency Polymer Solar Cells
Abstract: Low bandgap n-type organic semiconductor (n-OS) ITIC has attracted great attention for the application as an acceptor with medium bandgap p-type conjugated polymer as donor in nonfullerene polymer solar cells (PSCs) because of its attractive photovoltaic performance. Here we report a modification on the molecular structure of ITIC by side-chain isomerization with meta-alkyl-phenyl substitution, m-ITIC, to further improve its photovoltaic performance. In a comparison with its isomeric counterpart ITIC with para-alkyl-phenyl substitution, m-ITIC shows a higher film absorption coefficient, a larger crystalline coherence, and higher electron mobility. These inherent advantages of m-ITIC resulted in a higher power conversion efficiency (PCE) of 11.77% for the nonfullerene PSCs with m-ITIC as acceptor and a medium bandgap polymer J61 as donor, which is significantly improved over that (10.57%) of the corresponding devices with ITIC as acceptor. To the best of our knowledge, the PCE of 11.77% is one of the highest values reported in the literature to date for nonfullerene PSCs. More importantly, the m-ITIC-based device shows less thickness-dependent photovoltaic behavior than ITIC-based devices in the active-layer thickness range of 80-360 nm, which is beneficial for large area device fabrication. These results indicate that m-ITIC is a promising low bandgap n-OS for the application as an acceptor in PSCs, and the side-chain isomerization could be an easy and convenient way to further improve the photovoltaic performance of the donor and acceptor materials for high efficiency PSCs.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: High-Performance Electron Acceptor with Thienyl Side Chains for Organic Photovoltaics
Abstract: We develop an efficient fused-ring electron acceptor (ITIC-Th) based on indacenodithieno[3,2-b]thiophene core and thienyl side-chains for organic solar cells (OSCs). Relative to its counterpart with phenyl side-chains (ITIC), ITIC-Th shows lower energy levels (ITIC-Th: HOMO = -5.66 eV, LUMO = -3.93 eV; ITIC: HOMO = -5.48 eV, LUMO = -3.83 eV) due to the σ-inductive effect of thienyl side-chains, which can match with high-performance narrow-band-gap polymer donors and wide-band-gap polymer donors. ITIC-Th has higher electron mobility (6.1 × 10(-4) cm(2) V(-1) s(-1)) than ITIC (2.6 × 10(-4) cm(2) V(-1) s(-1)) due to enhanced intermolecular interaction induced by sulfur-sulfur interaction. We fabricate OSCs by blending ITIC-Th acceptor with two different low-band-gap and wide-band-gap polymer donors. In one case, a power conversion efficiency of 9.6% was observed, which rivals some of the highest efficiencies for single junction OSCs based on fullerene acceptors.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: A near-infrared non-fullerene electron acceptor for high performance polymer solar cells
Abstract: Low-bandgap polymers/molecules are an interesting family of semiconductor materials, and have enabled many recent exciting breakthroughs in the field of organic electronics, especially for organic photovoltaics (OPVs). Here, such a low-bandgap (1.43 eV) non-fullerene electron acceptor (BT-IC) bearing a fused 7-heterocyclic ring with absorption edge extending to the near-infrared (NIR) region was specially designed and synthesized. Benefitted from its NIR light harvesting, high performance OPVs were fabricated with medium bandgap polymers (J61 and J71) as donors, showing power conversion efficiencies of 9.6% with J61 and 10.5% with J71 along with extremely low energy loss (0.56 eV for J61 and 0.53 eV for J71). Interestingly, femtosecond transient absorption spectroscopy studies on both systems show that efficient charge generation was observed despite the fact that the highest occupied molecular orbital (HOMO)–HOMO offset (ΔEH) in the blends was as low as 0.10 eV, suggesting that such a small ΔEH is not a crucial limitation in realizing high performance of NIR non-fullerene based OPVs. Our results indicated that BT-IC is an interesting NIR non-fullerene acceptor with great potential application in tandem/multi-junction, semitransparent, and ternary blend solar cells.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Halogenated conjugated molecules for ambipolar field-effect transistors and non-fullerene organic solar cells
Abstract: A series of halogenated conjugated molecules, containing F, Cl, Br and I, were easily prepared via Knoevenagel condensation and applied in field-effect transistors and organic solar cells. Halogenated conjugated materials were found to possess deep frontier energy levels and high crystallinity compared to their non-halogenated analogues, which is due to the strong electronegativity and heavy atom effect of halogens. As a result, halogenated semiconductors provide high electron mobilities up to 1.3 cm2 V−1 s−1 in transistors and high efficiencies over 9% in non-fullerene solar cells.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Enhancing Performance of Nonfullerene Acceptors via Side‐Chain Conjugation Strategy
Abstract: A side‐chain conjugation strategy in the design of nonfullerene electron acceptors is proposed, with the design and synthesis of a side‐chain‐conjugated acceptor (ITIC2) based on a 4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]di(cyclopenta‐dithiophene) electron‐donating core and 1,1‐dicyanomethylene‐3‐indanone electron‐withdrawing end groups. ITIC2 with the conjugated side chains exhibits an absorption peak at 714 nm, which redshifts 12 nm relative to ITIC1. The absorption extinction coefficient of ITIC2 is 2.7 × 105m−1 cm−1, higher than that of ITIC1 (1.5 × 105m−1 cm−1). ITIC2 exhibits slightly higher highest occupied molecular orbital (HOMO) (−5.43 eV) and lowest unoccupied molecular orbital (LUMO) (−3.80 eV) energy levels relative to ITIC1 (HOMO: −5.48 eV; LUMO: −3.84 eV), and higher electron mobility (1.3 × 10−3 cm2 V−1 s−1) than that of ITIC1 (9.6 × 10−4 cm2 V−1 s−1). The power conversion efficiency of ITIC2‐based organic solar cells is 11.0%, much higher than that of ITIC1‐based control devices (8.54%). Our results demonstrate that side‐chain conjugation can tune energy levels, enhance absorption, and electron mobility, and finally enhance photovoltaic performance of nonfullerene acceptors.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Design, synthesis, and structural characterization of the first dithienocyclopentacarbazole-based n-type organic semiconductor and its application in non-fullerene polymer solar cells
Abstract: Ladder-type dithienocyclopentacarbazole (DTCC) cores, which possess highly extended π-conjugated backbones and versatile modular structures for derivatization, were widely used to develop high-performance p-type polymeric semiconductors. However, an n-type DTCC-based organic semiconductor has not been reported to date. In this study, the first DTCC-based n-type organic semiconductor (DTCC–IC) with a well-defined A–D–A backbone was designed, synthesized, and characterized, in which a DTCC derivative substituted by four p-octyloxyphenyl groups was used as the electron-donating core and two strongly electron-withdrawing 3-(dicyanomethylene)indan-1-one moieties were used as the terminal acceptors. It was found that DTCC–IC has strong light-capturing ability in the range of 500–720 nm and exhibits an impressively high molar absorption coefficient of 2.24 × 105 M−1 cm−1 at 669 nm owing to effective intramolecular charge transfer and a strong D–A effect. Cyclic voltammetry measurements indicated that the HOMO and LUMO energy levels of DTCC–IC are −5.50 and −3.87 eV, respectively. More importantly, a high electron mobility of 2.17 × 10−3 cm2 V−1 s−1 was determined by the space-charge-limited current method; this electron mobility can be comparable to that of fullerene derivative acceptors (μe ∼ 10−3 cm2 V−1 s−1). To investigate its application potential in non-fullerene solar cells, we fabricated organic solar cells (OSCs) by blending a DTCC–IC acceptor with a PTB7-Th donor under various conditions. The results suggest that the optimized device exhibits a maximum power conversion efficiency (PCE) of up to 6% and a rational high VOC of 0.95 V. These findings demonstrate that the ladder-type DTCC core is a promising building block for the development of high-mobility n-type organic semiconductors for OSCs.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: A Twisted Thieno[3,4-b
]thiophene-Based Electron Acceptor Featuring a 14-π-Electron Indenoindene Core for High-Performance Organic Photovoltaics
Abstract: With an indenoindene core, a new thieno[3,4‐b]thiophene‐based small‐molecule electron acceptor, 2,2′‐((2Z,2′Z)‐((6,6′‐(5,5,10,10‐tetrakis(2‐ethylhexyl)‐5,10‐dihydroindeno[2,1‐a]indene‐2,7‐diyl)bis(2‐octylthieno[3,4‐b]thiophene‐6,4‐diyl))bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile (NITI), is successfully designed and synthesized. Compared with 12‐π‐electron fluorene, a carbon‐bridged biphenylene with an axial symmetry, indenoindene, a carbon‐bridged E‐stilbene with a centrosymmetry, shows elongated π‐conjugation with 14 π‐electrons and one more sp3 carbon bridge, which may increase the tunability of electronic structure and film morphology. Despite its twisted molecular framework, NITI shows a low optical bandgap of 1.49 eV in thin film and a high molar extinction coefficient of 1.90 × 105m−1 cm−1 in solution. By matching NITI with a large‐bandgap polymer donor, an extraordinary power conversion efficiency of 12.74% is achieved, which is among the best performance so far reported for fullerene‐free organic photovoltaics and is inspiring for the design of new electron acceptors.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Fused Hexacyclic Nonfullerene Acceptor with Strong Near‐Infrared Absorption for Semitransparent Organic Solar Cells with 9.77% Efficiency
Abstract: A fused hexacyclic electron acceptor, IHIC, based on strong electron‐donating group dithienocyclopentathieno[3,2‐b]thiophene flanked by strong electron‐withdrawing group 1,1‐dicyanomethylene‐3‐indanone, is designed, synthesized, and applied in semitransparent organic solar cells (ST‐OSCs). IHIC exhibits strong near‐infrared absorption with extinction coefficients of up to 1.6 × 105m−1 cm−1, a narrow optical bandgap of 1.38 eV, and a high electron mobility of 2.4 × 10−3 cm2 V−1 s−1. The ST‐OSCs based on blends of a narrow‐bandgap polymer donor PTB7‐Th and narrow‐bandgap IHIC acceptor exhibit a champion power conversion efficiency of 9.77% with an average visible transmittance of 36% and excellent device stability; this efficiency is much higher than any single‐junction and tandem ST‐OSCs reported in the literature.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Naphthodithiophene‐Based Nonfullerene Acceptor for High‐Performance Organic Photovoltaics: Effect of Extended Conjugation
Abstract: Naphtho[1,2‐b:5,6‐b′]dithiophene is extended to a fused octacyclic building block, which is end capped by strong electron‐withdrawing 2‐(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐inden‐1‐ylidene)malononitrile to yield a fused‐ring electron acceptor (IOIC2) for organic solar cells (OSCs). Relative to naphthalene‐based IHIC2, naphthodithiophene‐based IOIC2 with a larger π‐conjugation and a stronger electron‐donating core shows a higher lowest unoccupied molecular orbital energy level (IOIC2: −3.78 eV vs IHIC2: −3.86 eV), broader absorption with a smaller optical bandgap (IOIC2: 1.55 eV vs IHIC2: 1.66 eV), and a higher electron mobility (IOIC2: 1.0 × 10−3 cm2 V−1 s−1 vs IHIC2: 5.0 × 10−4 cm2 V−1 s−1). Thus, IOIC2‐based OSCs show higher values in open‐circuit voltage, short‐circuit current density, fill factor, and thereby much higher power conversion efficiency (PCE) values than those of the IHIC2‐based counterpart. In particular, as‐cast OSCs based on FTAZ: IOIC2 yield PCEs of up to 11.2%, higher than that of the control devices based on FTAZ: IHIC2 (7.45%). Furthermore, by using 0.2% 1,8‐diiodooctane as the processing additive, a PCE of 12.3% is achieved from the FTAZ:IOIC2‐based devices, higher than that of the FTAZ:IHIC2‐based devices (7.31%). These results indicate that incorporating extended conjugation into the electron‐donating fused‐ring units in nonfullerene acceptors is a promising strategy for designing high‐performance electron acceptors.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Dithieno[3,2-b
:2′,3′-d
]pyrrol Fused Nonfullerene Acceptors Enabling Over 13% Efficiency for Organic Solar Cells
Abstract: A new electron‐rich central building block, 5,5,12,12‐tetrakis(4‐hexylphenyl)‐indacenobis‐(dithieno[3,2‐b:2′,3′‐d]pyrrol) (INP), and two derivative nonfullerene acceptors (INPIC and INPIC‐4F) are designed and synthesized. The two molecules reveal broad (600–900 nm) and strong absorption due to the satisfactory electron‐donating ability of INP. Compared with its counterpart INPIC, fluorinated nonfullerene acceptor INPIC‐4F exhibits a stronger near‐infrared absorption with a narrower optical bandgap of 1.39 eV, an improved crystallinity with higher electron mobility, and down‐shifted highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. Organic solar cells (OSCs) based on INPIC‐4F exhibit a high power conversion efficiency (PCE) of 13.13% and a relatively low energy loss of 0.54 eV, which is among the highest efficiencies reported for binary OSCs in the literature. The results demonstrate the great potential of the new INP as an electron‐donating building block for constructing high‐performance nonfullerene acceptors for OSCs.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: Dithienopicenocarbazole-Based Acceptors for Efficient Organic Solar Cells with Optoelectronic Response Over 1000 nm and an Extremely Low Energy Loss
Abstract: Two cheliform non-fullerene acceptors, DTPC-IC and DTPC-DFIC, based on a highly electron-rich core, dithienopicenocarbazole (DTPC), are synthesized, showing ultra-narrow bandgaps (as low as 1.21 eV). The two-dimensional nitrogen-containing conjugated DTPC possesses strong electron-donating capability, which induces intense intramolecular charge transfer and intermolecular π-π stacking in derived acceptors. The solar cell based on DTPC-DFIC and a spectrally complementary polymer donor, PTB7-Th, showed a high power conversion efficiency of 10.21% and an extremely low energy loss of 0.45 eV, which is the lowest among reported efficient OSCs.
Extracted statement — Mobility: Electron
Research field: Materials Chemistry
Title: A Solution-Processable Electron Acceptor Based on Dibenzosilole and Diketopyrrolopyrrole for Organic Solar Cells
Abstract: Organic solar cells (OSCs) are a promising cost-effective alternative for utility of solar energy, and possess low-cost, light-weight, and fl exibility advantages. [ 1–7 ] Much attention has been focused on the development of OSCs which have seen a dramatic rise in effi ciency over the last decade, and the encouraging power conversion effi ciency (PCE) over 9% has been achieved from bulk heterojunction (BHJ) OSCs. [ 8 ] With regard to photoactive materials, fullerenes and their derivatives, such as [6,6]-phenyl C 61 butyric acid methyl ester (PC 61 BM), have been the dominant electron-acceptor materials in BHJ OSCs, owing to their high electron mobility, large electron affi nity and isotropy of charge transport. [ 9 ] However, fullerenes have a few disadvantages, such as restricted electronic tuning and weak absorption in the visible region. Furthermore, in typical BHJ system of poly(3-hexylthiophene) (P3HT):PC 61 BM, mismatching energy levels between donor and acceptor leads to energy loss and low open-circuit voltages ( V OC ). To solve these problems, novel electron acceptor materials with strong and broad absorption spectra and appropriate energy levels are necessary for OSCs. Recently, non-fullerene small molecule acceptors have been developed. [ 10 , 11 ] However, rare reports on the devices based on solution-processed non-fullerene small molecule acceptors have shown PCEs approaching or exceeding 1.5%, [ 12–19 ] and only one paper reported PCEs over 2%. [ 16 ]
Extracted statement — Mobility type: Electron
Research field: Materials Chemistry
Title: A Rhodanine Flanked Nonfullerene Acceptor for Solution-Processed Organic Photovoltaics
Abstract: A novel small molecule, FBR, bearing 3-ethylrhodanine flanking groups was synthesized as a nonfullerene electron acceptor for solution-processed bulk heterojunction organic photovoltaics (OPV). A straightforward synthesis route was employed, offering the potential for large scale preparation of this material. Inverted OPV devices employing poly(3-hexylthiophene) (P3HT) as the donor polymer and FBR as the acceptor gave power conversion efficiencies (PCE) up to 4.1%. Transient and steady state optical spectroscopies indicated efficient, ultrafast charge generation and efficient photocurrent generation from both donor and acceptor. Ultrafast transient absorption spectroscopy was used to investigate polaron generation efficiency as well as recombination dynamics. It was determined that the P3HT:FBR blend is highly intermixed, leading to increased charge generation relative to comparative devices with P3HT:PC60BM, but also faster recombination due to a nonideal morphology in which, in contrast to P3HT:PC60BM devices, the acceptor does not aggregate enough to create appropriate percolation pathways that prevent fast nongeminate recombination. Despite this nonoptimal morphology the P3HT:FBR devices exhibit better performance than P3HT:PC60BM devices, used as control, demonstrating that this acceptor shows great promise for further optimization.
Extracted statement — Mobility type: Electron
Research field: Materials Chemistry
Title: π-Bridge-Independent 2-(Benzo[c][1,2,5]thiadiazol-4-ylmethylene)malononitrile-Substituted Nonfullerene Acceptors for Efficient Bulk Heterojunction Solar Cells
Abstract: Molecular acceptors are promising alternatives to fullerenes (e.g., PC61/71BM) in the fabrication of high-efficiency bulk-heterojunction (BHJ) solar cells. While solution-processed polymer–fullerene BHJ devices have recently met the 10% efficiency threshold, molecular acceptors have yet to prove comparably efficient with polymer donors. At this point in time, it is important to forge a better understanding of the design parameters that directly impact small-molecule (SM) acceptor performance in BHJ solar cells. In this report, we show that 2-(benzo[c][1,2,5]thiadiazol-4-ylmethylene)malononitrile (BM)-terminated SM acceptors can achieve efficiencies as high as 5.3% in BHJ solar cells with the polymer donor PCE10. Through systematic device optimization and characterization studies, we find that the nonfullerene analogues (FBM, CBM, and CDTBM) all perform comparably well, independent of the molecular structure and electronics of the π-bridge that links the two electron-deficient BM end groups. With estimated...
Extracted statement — Mobility type: Electron
Research field: Materials Chemistry
Title: Push–Pull Type Non-Fullerene Acceptors for Polymer Solar Cells: Effect of the Donor Core
Abstract: There has been a growing interest in the design and synthesis of non-fullerene acceptors for organic solar cells that may overcome the drawbacks of the traditional fullerene-based acceptors. Herein, two novel push-pull (acceptor-donor-acceptor) type small-molecule acceptors, that is, ITDI and CDTDI, with indenothiophene and cyclopentadithiophene as the core units and 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (INCN) as the end-capping units, are designed and synthesized for non-fullerene polymer solar cells (PSCs). After device optimization, PSCs based on ITDI exhibit good device performance with a power conversion efficiency (PCE) as high as 8.00%, outperforming the CDTDI-based counterparts fabricated under identical condition (2.75% PCE). We further discuss the performance of these non-fullerene PSCs by correlating the energy level and carrier mobility with the core of non-fullerene acceptors. These results demonstrate that indenothiophene is a promising electron-donating core for high-performance non-fullerene small-molecule acceptors.
Extracted statement — Mobility type: Electron
Research field: Materials Chemistry
Title: Nonfullerene Polymer Solar Cells Based on a Main-Chain Twisted Low-Bandgap Acceptor with Power Conversion Efficiency of 13.2%
Abstract: A new acceptor–donor–acceptor-structured nonfullerene acceptor, 2,2′-((2Z,2′Z)-(((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-4,3-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (i-IEICO-4F), is designed and synthesized via main-chain substituting position modification of 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene)dimalononitrile. Unlike its planar analogue IEICO-4F with strong absorption in the near-infrared region, i-IEICO-4F exhibits a twisted main-chain configuration, resulting in 164 nm blue shifts and leading to complementary absorption with the wide-bandgap polymer (J52). A high solution molar extinction coefficient of 2.41 × 105 M–1 cm–1, and sufficiently high energy of charge-transfer excitons of 1.15 eV in a J52:i-IEICO-4F blend were observed, in comparison with those of 2.26 × 105 M–1 cm–1 and 1.08 eV for IEICO-4F. A power conversion efficiency of...
Extracted statement — Acceptor: i-IEICO-4F