Thieno[3,4-c]pyrrole-4,6-dione Research Articles

Small Molecules Derived from Thieno[3,4-c]pyrrole-4,6-dione (TPD) and Their Use in Solution Processed Organic Solar Cells.

In this work, microwave synthesis, chemical, optical and electrochemical characterization of three small organic molecules, TPA-TPD, TPA-PT-TPD and TPA-TT-TPD with donor-acceptor structure and their use in organic photovoltaic cells are reported. For the synthesis, 5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione was used as electron withdrawing fragment while the triphenylamine was used as electron donating fragment. Molecular electronic geometry and electronic distribution density were established by density functional theory (DFT) calculations and confirmed by optical and chemical characterization. These molecules were employed as electron-donors in the active layer for manufacturing bulk heterojunction organic solar cells, where [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) was used as electron-acceptor. As cathode, Field′s metal (FM), an eutectic alloy (Bi/In/Sn: 32.5%, 51%, and 16.5%, respectively) with a melting point above 62 °C, was easily deposited by drop casting under vacuum-free process and at air atmosphere. Prepared devices based on TPA-TPD:PC71BM (1:4 w/w ratio) presented a large VOC = 0.97 V, with JSC = 7.9 mA/cm2, a FF = 0.34, then, a power conversion efficiency (PCE) of 2.6%.

Steric‐Hindrance Modulation toward High‐Performance 1,3‐Bis(thieno[3,4‐b]thiophen‐6‐yl)‐4H‐thieno[3,4‐c]pyrrole‐4,6(5H)‐dione‐Based Polymer Solar Cells with Enhanced Open‐Circuit Voltage

AbstractSolution‐processed bulk‐heterojunction polymer solar cells (PSCs) are indispensable in photovoltaics. π‐Conjugated donor–acceptor copolymers as electron donors have become the cornerstone as the most intensively studied topic in this field. Thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) is one of the most commonly used electron‐withdrawing moieties. Based on TPD, a new building block, 1,3‐bis(thieno[3,4‐b]thiophen‐6‐yl)‐4H‐thieno[3,4‐c]pyrrole‐4,6(5H)‐dione (TBTT), is designed and a novel low‐bandgap TPD‐copolymer is developed with a power conversion efficiency (PCE) up to 7.5% with a low open‐circuit voltage (Voc) of 0.633 V when utilizing PC71BM as electron acceptor. To promote the performance of TBTT‐based polymers, four conjugated copolymers are designed and synthesized based on TBTT and benzodithiophene (BDT) building blocks by regulating their steric hindrance with side alkyl chains on BDT moiety. PSCs based on polymer P4 with an additional n‐hexyl side chain blended with PC71BM deliver a high PCE of 9.1% with a Voc of 0.78 V increased by 24%, which is among the highest in TPD‐based polymers. The study provides new insights into the molecular design and synthesis of high‐performance photovoltaic materials.

Interface engineering on phenanthrocarbazole/thienopyrroledione-based conjugated polymer for efficient organic photovoltaic devices with ideal nano-morphology and improved charge carrier dynamics

We synthesized PP-TPD, based on a phenanthro[1,10,9,8-cdefg]carbazole unit as a donor and a thieno [3,4-c]pyrrole-4,6-dione (TPD) unit as an acceptor for efficient bulk heterojunction photovoltaic cells. The copolymer achieves a relatively low bandgap (1.6 eV) by its internal charge-transfer, which concurs with the results of density functional theory (DFT) calculation for the distribution of HOMO and LUMO levels. In addition, we fabricated the bulk-heterojunction (BHJ) photovoltaic cells as a function of the blend ratio of the donor (PP-TPD) and acceptor (PC70BM), and applied a solvent additive and an interlayer to the device, with the optimized ratio used in this study. To comprehend the relationships between the device performance and the synergetic effects of 1,8-diiodooctane (DIO) and titanium oxide (TiOx) within the PP-TPD: PC70BM blends, we investigated the hole mobility related to the charge carrier transport, the charge generation, and the charge transport resistance using space-charge limited current (SCLC) measurement, photocurrent analysis, and impedance spectroscopy, respectively. Especially, we implemented fluorescence imaging by Raman spectroscopy, which related to the charge generation and recombination dynamics within the surface of photoactive areas.

Thieno[3,4‐c]Pyrrole‐4,6‐Dione‐Based Polymer Acceptors for High Open‐Circuit Voltage All‐Polymer Solar Cells

While polymer acceptors are promising fullerene alternatives in the fabrication of efficient bulk heterojunction (BHJ) solar cells, the range of efficient material systems relevant to the “all‐polymer” BHJ concept remains narrow, and currently limits the perspectives to meet the 10% efficiency threshold in all‐polymer solar cells. This report examines two polymer acceptor analogs composed of thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) and 3,4‐difluorothiophene ([2F]T) motifs, and their BHJ solar cell performance pattern with a low‐bandgap polymer donor commonly used with fullerenes (PBDT‐TS1; taken as a model system). In this material set, the introduction of a third electron‐deficient motif, namely 2,1,3‐benzothiadiazole (BT), is shown to (i) significantly narrow the optical gap (Eopt) of the corresponding polymer (by ≈0.2 eV) and (ii) improve the electron mobility of the polymer by over two orders of magnitude in BHJ solar cells. In turn, the narrow‐gap P2TPDBT[2F]T analog (Eopt = 1.7 eV) used as fullerene alternative yields high open‐circuit voltages (VOC) of ≈1.0 V, notable short‐circuit current values (JSC) of ≈11.0 mA cm−2, and power conversion efficiencies (PCEs) nearing 5% in all‐polymer BHJ solar cells. P2TPDBT[2F]T paves the way to a new, promising class of polymer acceptor candidates.

Random D–A1–D–A2terpolymers based on benzodithiophene, thiadiazole[3,4-e]isoindole-5,7-dione and thieno[3,4-c]pyrrole-4,6-dione for efficient polymer solar cells

New efficient D–A1–D–A2random terpolymers for photovoltaic applications.

ChemInform Abstract: Thieno[3,4‐c]pyrrole‐4,6‐dione Based Copolymers for High Performance Organic Solar Cells and Organic Field Effect Transistors

AbstractReview: 35 refs.

Synthesis and Characterization of Two-Dimensional Conjugated Polymers Incorporating Electron-Deficient Moieties for Application in Organic Photovoltaics.

A series of novel p-type conjugated copolymers, PTTVBDT, PTTVBDT-TPD, and PTTVBDT-DPP, cooperating benzo[1,2-b:4,5-b′]dithiophene (BDT) and terthiophene-vinylene (TTV) units with/without thieno[3,4-c]pyrrole-4,6-dione (TPD) or pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) via Stille polymerization were synthesized and characterized. Copolymer PTTVBDT shows a low-lying HOMO energy level and ordered molecular-packing behavior. Furthermore, two terpolymers, PTTVBDT-TPD and PTTVBDT-DPP, display stronger absorption ability, alower-lying HOMO energy level, and preferred molecular orientation, due to the replacement TTV-monomer units with electron-deficient groups. Furthermore, bulk-heterojunction organic solar cells were fabricated using blends of the PTTVBDT-TPD, and PC61BM gave the best power conversion efficiency of 5.01% under the illumination of AM 1.5G, 100 mW·cm−2; the short circuit current (Jsc) was 11.65 mA·cm−2 which displayed a 43.8% improvement in comparison with the PTTVBDT/PC61BM device. These results demonstrate a valid strategy combining the two-dimensional molecular structure with random copolymerization strikes promising conjugated polymers to achieve highly efficient organic photovoltaics.

Preparation and photovoltaic properties of pyrene-thieno[3,4-c]pyrrole-4,6-dione-based donor-acceptor polymers

Four new donor-acceptor conjugated copolymers, containing pyrene moieties flanked by thienyl or bithienyl groups as a donor units and thieno[3,4-c]pyrrole-4,6-dione (TPD) as acceptor units, were successfully prepared via a direct arylation polymerisation method. While all polymers prepared had 2-ethylhexyloxy-substituents on the pyrene repeat units, two different alkyl-substituents (octyl or 4-hexylphenyl groups) were attached to their TPD moieties. The influence of these different substituents as well as the number of thienyl units linking the pyrene and TPD units along polymer chains on the photophysical, electronic and photovoltaic properties of these materials was investigated. All polymers displayed good thermal stability up to 315°C. The optical band gap of the four polymers, PPEHDT-TPDO, PPEHDT-TPDHP, PPEHDT2-TPDO and PPEHDT2-TPDHP, were estimated to be 2.00, 2.06, 1.94 and 1.91eV, respectively. Polymers that possessed a single thiophene unit attached to the pyrene unit, PPEHDT-TPDO and PPEHDT-TPDHP, displayed deeper HOMO levels compared to those with bithiophene units, PPEHDT2-TPDO and PPEHDT2-TPDHP. Photovoltaic devices were fabricated from all polymers. PPEHDT2-TPDO boasted the highest efficiency with a PCE (2.06%), a FF of 53.07%, a Jsc of 4.66mA/cm2 and a Voc of 0.83V.

Double acceptor donor–acceptor alternating conjugated polymers containing cyclopentadithiophene, benzothiadiazole and thienopyrroledione: toward subtractive color organic photovoltaics

Double acceptor copolymers comprising benzothiadiazole (BT), thieno[3,4-c]pyrrole-4,6-dione (TPD) and two cyclopentadithiophene (CPDT) units, and a series of copolymers comprising CPDT-A-CPDT (A: acceptor=BT or TPD) with different numbers of thiophene units have been synthesized by combinations of Suzuki and Stille coupling, direct arylation and oxidative polymerization. Ultraviolet–visible absorption spectra and cyclic voltammograms were measured to compare the optical and electrochemical properties of the polymers. The double acceptor copolymer exhibited hybridized features resulting from the presence of both BT, as well as TPD. On the other hand, an increase in the number of electron donor units resulted in an increase in the band gap for both the TPD and BT series. Organic photovoltaics (OPV) devices were fabricated using the polymers and a fullerene derivative. These donor–acceptor alternating copolymers showed higher OPV performance (power conversion efficiency=3–4%) than other polymers. The active layer comprising the double acceptor polymer and a fullerene derivative showed subtractive color resulting from wide-range visible light absorption, which is advantageous for developing transparent building-integrated OPVs. The OPV performance of BT-based copolymers synthesized via direct arylation was comparable or lower compared with those prepared by conventional cross-coupling polymerizations. Double acceptor donor–acceptor alternating conjugated copolymers comprising thienopyrroledione, benzothiadiazole, two cyclopentadithiophene groups and their analogs with thiophene or bithiophene units have been synthesized by combinations of direct arylation, Suzuki and Stille coupling and oxidative polymerization. These polymers were used to fabricate bulk heterojunction organic photovoltaic (OPV) devices with fullerene derivatives. The active layer comprising the double acceptor polymer with fullerene derivatives showed a subtractive color resulting from wide-range visible light absorption, which is advantageous for practical OPV applications.

Alkoxyl Side Chain Substituted Thieno[3,4-c]pyrrole-4,6-dione To Enhance Photovoltaic Performance with Low Steric Hindrance and High Dipole Moment

A series of N-OR substituted thieno[3,4-c]pyrrole-4,6-dione (TPD) and benzo[1,2-b:4,5-b′]dithiophene (BDT) based copolymers are systematically investigated. The replacing CH2 with smaller size oxygen atom not only reduces the steric hindrance but also enhances the dipole moment (Δμge), which is in favor of charge separation. while the optical and electrochemical properties almost remain unchanged due to the alkoxyl chain on TPD unit not conjugated with the backbone. Consequently, the PBT-O8 based solar cell devices yield a remarkable short-circuit current density (JSC) of up to 14.3 mA/cm2 and power conversion efficiency (PCE) of 8.22%, which exhibits an increase of 10% in comparison with that of PBT-C8 (PCE 7.50%). Furthermore, the PCEs increase almost linearly with decreasing side chain length from O12 to O10 to O8. Apart from the novel TPD analogues reported here, this work also provides a new insight into the ingenious use of alkoxyl side chain to improve the photovoltaic performance.

Thieno[3,4-c]pyrrole-4,6-dione based copolymers for high performance organic solar cells and organic field effect transistors

Abstract Donor–acceptor type copolymers have wide applications in organic field-effect transistors and organic photovoltaic devices. Thieno[3,4-c]pyrrole-4,6-dione (TPD), as an electron-withdrawing unit, has been widely used in D–A type copolymers recently. Till now, the highest power conversion efficiency and mobility of TPD-based copolymers are over 8% and 1.0 cm2 V−1 s−1 respectively. In this review, the recent progress of TPD-based copolymers in organic solar cells and organic transistors is summarized.

Thieno[3,4-c]Pyrrole-4,6-Dione and Dithiophene-Based Conjugated Polymer for Organic Field Effect Transistors: High Mobility Induced by Synergic Effect of H-Bond and Vinyl Linkage.

Here, a conjugated polymer VTTPD based on thieno[3,4-c]pyrrole-4,6-dione (TPD) and dithiophene with vinyl as linker is synthesized and characterized. Electrochemical and optical studies indicate the LUMO and HOMO energies of the polymer are -3.70 and -5.39 eV. Theoretical calculation with density functional theory suggests that H-bonds are formed between the TPD carbonyl (O) and its neighboring vinyl (H) which benefit the planarity and π-conjugation of the polymer backbone. Bottom contact bottom gate organic field effect transistor devices based on VTTPD are fabricated and examined in air. After annealing at 160 °C, the devices exhibit excellent performance of μh = 0.4 cm(2) V(-1) s(-1) , Ion/off = 10(6) , Vth within -10 V to -5 V. Thin film morphologies before and after the annealing process are also investigated with XRD and AFM.

D(A-A′)2 architecture: An efficient strategy to improve photovoltaic performance of small molecules for solution-processed organic solar cells

Two novel small molecules (SMs) of BDT(TPD-DPP)2 and BDTT(TPD-DPP)2 with a D(A-A′)2 framework were designed and synthesized, in which the electron-rich benzodithiophene (BDT) and thiophenyl-substituted benzodithiophene (BDTT) are used as a central donor (D) core, as well as the electron-deficient diketopyrrolopyrrole (DPP) and thieno [3,4-c]pyrrole-4,6-dione (TPD) as dual acceptor (A and A′) units, respectively. Their optical, electrochemical, and photovoltaic properties were investigated together with their counterparts, which bearing an accepter-donor-accepter (A-D-A) architecture. Wider and stronger solar photon responses and decreasing the lowest unoccupied orbital (LUMO) levels are observed in the D(A-A′)2 rather than A-D-A type SMs. The significantly increasing power conversion efficiency of 4.25% with a short-circuit current density of 10.08 mA cm−2 were obtained in the BDTT(TPD-DPP)2 based solar cells. This work demonstrates that using D(A-A′)2 architecture with dual acceptor units is an effective method to improve photovoltaic performance of SMs for solution-processed organic solar cells.

Single precursor for the synthesis of donor and acceptor units of the low band gap polymers: synthesis of benzodithiophene and thienopyrroledione from maleic anhydride

An efficient route was developed to synthesize dimethyl thiophene-3,4-dicarboxylate from maleic anhydride. Dimethyl thiophene-3,4-dicarboxylate was used as a single precursor for synthesis of benzo[1,2-b:4,5-b′]dithiophene (BDT) and Thieno[3,4-c]pyrrole-4,6-dione (TPD) derivatives. BDT and TPD derivatives have been highly exploited as donor and acceptor units, respectively, to synthesize important donor–acceptor (D–A) conjugated polymers. BDT-based polymers were found to be one of the most efficient conjugated polymers for organic photovoltaic application. Synthesis of quinone precursor of the dihydroxybenzothiophene was accomplished by a new and unconventional methodology which includes reaction of 3,4-thiophene dicarboxylate with sodium hydride in THF. Dithienobenzoquinone dicarboxylate and dihydroxybenzodithiophene dicarboxylate were characterized structurally by single-crystal X-ray diffraction. Both compounds show strong π-stacking interaction and arrange in the parallel molecular sheets in the crystals.

New bulky side chain substituted benzodithiophene based 2D-conjugated polymers for optoelectronic applications

In order to explore the effect of bulky side chain substituted benzodithiophene (BDT) based polymers on optoelectronic properties, here we have designed and synthesized two new 2D conjugated donor–acceptor (D–A) copolymers P1 and P2 via Stille coupling of 2,3-bis(4-(2-ethylhexyloxy)phenyl)thiophene (BAPT) substituted BDT as (D) unit and 1,3-di(2-bromothien-5-yl)-5-(2-ethylhexyl)thieno[3,4-c]pyrrole-4,6-dione (TPD) or 2,5-ethylhexyl-3,6-bis(5-bromothiophen-2-yl)pyrrolo[3,4-c]-pyrrole-1,4-dione (DPP) as (A) units. The new polymers P1 and P2 showed broad absorption windows with vibronic shoulders indicate π–π stacking of polymer backbones. In addition P1 and P2 showed deep highest occupied molecular orbital (HOMO) energy levels of −5.50, −5.35 eV, respectively which allow delivering high open-circuit voltages (Voc) in bulk heterojunction polymer solar cells (BHJ PSCs). The donor photon energy loss (Eg–eVoc) of P1 and P2 are 0.87 and 0.57 which is comparable to the previous reports. BHJ PSCs were fabricated with P1 and P2, and they displayed high Voc of 0.99 and 0.78 V, respectively, with maximum power conversion efficiency of 2.05 and 0.96 % in additive free BHJ PSCs. The polymer field effect transistor mobilities of P1 and P2 are 8.0 × 10−3, 9.2 × 10−5 cm2/V s, respectively.

TPD‐ and DPP‐based Small Molecule Donors Containing Pyridine End Groups for Organic Photovoltaic Cells

We synthesized two new thieno[3,4‐c]pyrrole‐4,6‐dione (TPD)‐ and diketopyrrolopyrrole (DPP)‐based small molecules having pyridine end groups, TPDTPy and DPPTPy, using the Stille and Suzuki coupling reactions, respectively. The optical, electrochemical, and photovoltaic properties of these small molecules depended on the introduced electron‐accepting units of TPD and DPP. DPPTPy exhibited a relatively low‐energy bandgap (Eg) of 1.82 eV compared to TPDTPy (2.22 eV) because of the stronger electron‐withdrawing ability of DPP compared to TPD. Organic photovoltaic cells with the inverted ITO/ZnO/small molecule:(6,6)‐phenyl‐C71‐butyric acid methyl ester/MoO3/Ag structure were fabricated. The DPPTPy‐based device showed a relatively high power conversion efficiency of 0.62% compared to TPDTPy (0.16%), mainly because of the red‐shifted UV absorption, lower Eg, and the higher short‐circuit current of DPPTPy.

Thiophene π bridge effect on bulky side‐chained benzodithiophene‐based photovoltaic polymers

ABSTRACTRecently, we have used terthiophene side chain to modify benzo[1,2‐b:4,5‐b′]dithiophene (BDT) to form novel building block for BDT polymers. In this paper, this building block is used to copolymerized with thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) and thieno[3,4‐b]thiophene (TT). This building block and TPD‐ or TT‐based polymers (P1 and P3) show high open circuit voltage (VOC) (ca. 0.9–0.95 V) and low energy loss (Eg–eVOC) in solar cells devices compared with similar polymers without bulky side chain. We further introduce thiophene π bridge into these polymers backbone to form two other polymers (P2 and P4). We find this thiophene π bridge does contribute to this bulky side chained benzodithiophene polymer photovoltaic performances, especially for power conversion efficiencies (PCEs). The polymer solar cells (PSCs) performances are moderate in this article due to the serious aggregation in the PSCs active layer. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1615–1622

Anthracene‐thieno[3,4‐c]pyrrole‐4,6‐dione based donor–acceptor conjugated copolymers for applications in optoelectronic devices

Three novel alternating copolymers of thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) and triisopropylsilylacetylene‐functionalized anthracene were prepared via Suzuki polymerization. Various solubilizing substituents were attached to the TPD moiety in order to ascertain the impact they have upon the optical, electrochemical, and thermal properties of the resulting polymers. All copolymers showed good solubility and thermal stability with decomposition temperatures in excess of 300°C. Optical properties revealed that PTATPD(O), PTATPD(DMO), and PTATPD(BP) displayed optical energy gaps in excess of 2.0 eV. It is speculated that steric repulsion between solubilizing groups on repeat units along polymer chains reduces their planarity and decreases their electronic conjugation. The amorphous nature of the polymers was confirmed with differential scanning calorimetry and powder X‐ray diffraction. The highest occupied molecular orbital levels of the three polymers are unaffected by the different solubilizing chains. However, they exert some influence over the lowest unoccupied molecular orbital (LUMO) levels with PTATPD(BP) and PTATPD(O) displaying the lowest LUMO levels (−3.4 eV). In contrast, PTATPD(DMO) displayed the highest LUMO level (−3.3 eV). © 2015 The Authors. Polymers for Advanced Technologies Published by John Wiley & Sons Ltd.

Marked Consequences of Systematic Oligothiophene Catenation in Thieno[3,4-c]pyrrole-4,6-dione and Bithiopheneimide Photovoltaic Copolymers.

As effective building blocks for high-mobility transistor polymers, oligothiophenes are receiving attention for polymer solar cells (PSCs) because the resulting polymers can effectively suppress charge recombination. Here we investigate two series of in-chain donor-acceptor copolymers, PTPDnT and PBTInT, based on thieno[3,4-c]pyrrole-4,6-dione (TPD) or bithiopheneimide (BTI) as electron acceptor units, respectively, and oligothiophenes (nTs) as donor counits, for high-performance PSCs. Intramolecular S···O interaction leads to more planar TPD polymer backbones, however backbone torsion yields greater open-circuit voltages for BTI polymers. Thiophene addition progressively raises polymer HOMOs but marginally affects their band gaps. FT-Raman spectra indicate that PTPDnT and PBTInT conjugation lengths scale with nT catenation up to n = 3 and then saturate for longer oligomer. Furthermore, the effects of oligothiophene alkylation position are explored, revealing that the alkylation pattern greatly affects film morphology and PSC performance. The 3T with "outward" alkylation in PTPD3T and PBTI3T affords optimal π-conjugation, close stacking, long-range order, and high hole mobilities (0.1 cm(2)/(V s)). These characteristics contribute to the exceptional ∼80% fill factors for PTPD3T-based PSCs with PCE = 7.7%. The results demonstrate that 3T is the optimal donor unit among nTs (n = 1-4) for photovoltaic polymers. Grazing incidence wide-angle X-ray scattering, transmission electron microscopy, and time-resolved microwave conductivity measurements reveal that the terthiophene-based PTPD3T blend maintains high crystallinity with appreciable local mobility and long charge carrier lifetime. These results provide fundamental materials structure-device performance correlations and suggest guidelines for designing oligothiophene-based polymers with optimal thiophene catenation and appropriate alkylation pattern to maximize PSC performance.

Thieno, Furo, and Selenopheno[3,4‐c]pyrrole‐4,6‐dione Copolymers: Air‐Processed Polymer Solar Cells with Power Conversion Efficiency up to 7.1%

Polymers based on thieno[3,4‐c]pyrrole‐4,6‐dione derivatives are interesting and promising candidates for organic bulk heterojunction solar cells. Herein, a series of push–pull conjugated polymers based on thieno[3,4‐c]pyrrole‐4,6‐dione (TPD), furo[3,4‐c]pyrrole‐4,6‐dione (FPD), and selenopheno[3,4‐c]‐pyrrole‐4,6‐dione (SePD) have been synthesized by direct heteroarylation polymerization and fully characterized. The impacts of both the heteroatom (sulfur, oxygen, and selenium) and the side chain (branched or linear) of [3,4‐c]pyrrole‐4,6‐dione unit on the electro‐optical properties have been investigated. Among polymers developed, two new highly processable terthiophene–SePD (P4) and dithienosilole–SePD (P9) copolymers led to air‐processed polymer solar cells with power conversion efficiencies of 5.1% and 7.1% using the following inverted configuration: ITO/ZnO/Polymer:PCBM/MoO3/Ag. These promising results make P4 and P9 good candidates for further upscaling and device optimization.