Application In Polymer Solar Cells Research Articles

Isatylidene malononitrile derived acceptors for fullerene free organic solar cells

New electron withdrawing moieties derived from isatin and its thiophene analogue were successfully incorporated into A-D-A structured molecular acceptors for polymer solar cell applications. The optical absorption and electrochemical properties of the new materials were investigated. The new acceptors showed low LUMO energy level, broad absorption in visible and near IR region and good miscibility with polymer donor, PTB7-Th. The solar cell devices based on the new electron acceptors and polymer electron donor, PTB7-Th achieved moderate performances. This work indicates that isatin related structures can be useful building blocks for small molecular acceptors.

Solution prepared O-doped ZnS nanocrystals: Structure characterization, energy level engineering and interfacial application in polymer solar cells

Doping impure atoms into host semiconductor nanocrystals is used to tune the properties and functions of semiconductor nanocrystals (NCs). Here, we demonstrate a solution method for preparing O doped ZnS (ZnS(O)) colloidal NCs. The as-prepared NCs have been proved to be consistent with the crystal structure of ZnS and Zn 3d-O 2p hydrization existed in the as-prepared NCs as certified by O k-edge X-ray absorption spectra (XAS). The average size was measured to be about 8.5 nm by Transmission Electron Microscope (TEM). The role of pyridines was to control the size and tune the surface property. By doping oxygen into ZnS lattice, the energy levels of as-prepared NCs were moved down, giving a better band alignment for photovoltaic application. When it was applied to modify ZnO interlayer and form ZnO/ZnS(O) bilayer in the polymer solar cells (PSCs), the optimal power conversion efficiency (PCE) of the device based on ZnO/ZnS(O) reached 8.85% (8.59 ± 0.49%), which increased by 10% compared to ZnO-only control device with the optimal PCE of 8.00% (7.46 ± 0.54%). The novel approach has been proved to be facile and scalable, paving the way for synthetizing O doped semiconductor nanocrystal.

"Double-Cable" Conjugated Polymers with Linear Backbone toward High Quantum Efficiencies in Single-Component Polymer Solar Cells.

A series of "double-cable" conjugated polymers were developed for application in efficient single-component polymer solar cells, in which high quantum efficiencies could be achieved due to the optimized nanophase separation between donor and acceptor parts. The new double-cable polymers contain electron-donating poly(benzodithiophene) (BDT) as linear conjugated backbone for hole transport and pendant electron-deficient perylene bisimide (PBI) units for electron transport, connected via a dodecyl linker. Sulfur and fluorine substituents were introduced to tune the energy levels and crystallinity of the conjugated polymers. The double-cable polymers adopt a "face-on" orientation in which the conjugated BDT backbone and the pendant PBI units have a preferential π-π stacking direction perpendicular to the substrate, favorable for interchain charge transport normal to the plane. The linear conjugated backbone acts as a scaffold for the crystallization of the PBI groups, to provide a double-cable nanophase separation of donor and acceptor phases. The optimized nanophase separation enables efficient exciton dissociation as well as charge transport as evidenced from the high-up to 80%-internal quantum efficiency for photon-to-electron conversion. In single-component organic solar cells, the double-cable polymers provide power conversion efficiency up to 4.18%. This is one of the highest performances in single-component organic solar cells. The nanophase-separated design can likely be used to achieve high-performance single-component organic solar cells.

Comprehensive Study on Chemical and Hot Press-Treated Silver Nanowires for Efficient Polymer Solar Cell Application.

In this study, chemical treatment (CT; oxidation–reduction method) and physical treatment (HP; hot-pressing methods) were applied to improve the performance of silver nanowire (AgNW)-derived electrodes on a glass or flexible polyethylene terephthalate (PET) substrate. The four-point probe method, UV-Vis spectroscopy and scanning electron microscopy (SEM) were used to measure the properties of AgNW electrodes and compare them with those of indium tin oxide (ITO) electrodes for exploring the possibility of using CT- and HP-based AgNW electrodes for polymer solar cell (PSC) applications. Using the CT or HP method, the sheet resistance of electrodes decreased to lower than 40 Ω sq−1 with an average high transmittance of more than 80%. Furthermore, HP reduced the surface roughness of AgNWs, which solved the inter-electrode short circuiting problem for devices. We studied the performance of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) and zinc oxide-based PSC devices. The power conversion efficiency of HP-AgNW-derived poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl] (PTB7-Th):[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) devices was 7.83%, which was slightly lower than the performance of the device using ITO (8.03%) as a substrate. After a bend test (100 times) at a 2-cm curvature radius, the efficiency of AgNW/PET-derived PSCs was more than 70%. The performance of PSCs made with AgNWs and ITO electrodes is comparable, but the cost of using AgNWs for electrodes is much lower; therefore, HP-derived AgNWs demonstrate great potential for optoelectronic applications.

Conjugated Polymers Based on Difluorobenzoxadiazole toward Practical Application of Polymer Solar Cells

AbstractTo advance polymer solar cells (PSCs) toward real‐world applications, it is crucial to develop materials that are compatible with a low‐cost large‐scale manufacturing technology. In this context, a practically useful polymer should fulfill several critical requirements: the capability to provide high power conversion efficiencies (PCEs) via low‐cost fabrication using environmentally friendly solvents under mild thermal conditions, resulting in an active layer that is thick enough to minimize defects in large‐area films. Here, the development of new photovoltaic polymers is reported through rational molecular design to meet these requirements. Benzodithiophene (BDT)‐difluorobenzoxadiazole (ffBX)‐2‐decyltetradecyl (DT), a wide‐bandgap polymer based on ffBX and BDT emerges as the first example that fulfills the qualifications. When blended with a low‐cost acceptor (C60‐fullerene derivative), BDT‐ffBX‐DT produces a PCE of 9.4% at active layer thickness over 250 nm. BDT‐ffBX‐DT devices can be fabricated from nonhalogenated solvents at low processing temperature. The success of BDT‐ffBX‐DT originates from its appropriate electronic structure and charge transport characteristics, in combination with a favorable face‐on orientation of the polymer backbone in blends, and the ability to form proper phase separation morphology with a fibrillar bicontinuous interpenetrating network in bulk‐heterojunction films. With these characteristics, BDT‐ffBX‐DT represents a meaningful step toward future everyday applications of polymer solar cells.

Side chain engineering of naphthalene diimide–bithiophene‐based polymer acceptors in all‐polymer solar cells

ABSTRACTTwo novel polymeric acceptors based on naphthalene diimide (NDI) and 2.2′‐bithiophene, named as P(NDI2THD‐T2) and P(NDI2TOD‐T2), were designed and synthesized for all polymer solar cells application. The structural and electronic properties of the two acceptors were modulated through side‐chain engineering of the NDI units. The optoelectronic properties of the polymers and the morphologies of the blend films composed of the polymer acceptors and a donor polymer PTB7‐Th were systemically investigated. With thiophene groups introduced into the side chains of the NDI units, both polymers showed wider absorption from 350 nm to 900 nm, compared with the reference polymer acceptor of N2200. No redshift of absorption spectra from solutions to films indicated reduced aggregation of the polymers due to the steric hindrance effect of thiophene rings in the side chains. The photovoltaic performance were characterized for devices in a configuration of ITO/PEDOT:PSS/PTB7‐Th:acceptors/2,9‐bis(3‐(dimethylamino)propyl)anthra[2,1,9‐def:6,5,10‐def]diisoquinoline‐1,3,8,10(2H,9H)‐tetraone (PDIN)/Al. With the addition of diphenyl ether as an additive, the power conversion efficiencies (PCEs) of 2.73% and 4.75% for P(NDI2THD‐T2) and P(NDI2TOD‐T2) based devices were achieved, respectively. The latter showed improved Jsc, Fill Factor (FF), and PCE compared with N2200 based devices. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3679–3689

Enhanced Long-term and Thermal Stability of Polymer Solar Cells in Air at High Humidity with the Formation of Unusual Quantum Dot Networks.

Due to the practical applications of polymer solar cells (PSCs), their stability recently has received increasing attention. Herein, a new strategy was developed to largely enhance the long-term and thermal stability of PSCs in air with a relatively high humidity of 50-60% without any encapsulation. In this strategy, semiconductor PbS/CdS core/shell quantum dots (QDs) were incorporated into the photoactive blend of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM). By replacing the initial ligands of oleic acid with halide ligands on the surface of PbS/CdS QDs via solution-phase ligand exchange, we were able to form unusual, continuous QD networks in the film of P3HT:PCBM, which effectively stabilized the photoactive layer. Air-processed PSCs based on the stabilized P3HT:PCBM film showed excellent long-term stability under high humidity, providing over 3% of power conversion efficiency (PCE) simultaneously. Around 91% of pristine PCE was retained after 30 days storage in high-humidity air without encapsulation. This constitutes a remarkable improvement compared to ∼53% retained PCE for the QD-free devices, which can be ascribed to the efficient suppression of both PCBM aggregation and oxidation of the thiophene ring in P3HT, thanks to the formation of robust QD networks. Furthermore, the presence of QD networks was able to enhance the stability of the P3HT:PCBM film against thermal stress/oxidation under high-humidity environment (50-60%) as well. The device kept 60% of pristine PCE after thermal treatment for 12 h at 85 °C in air, which is more than twice higher than that for the QD-free device. To the best of our knowledge, the work represents the first unambiguous demonstration of the formation of QD networks in the photoactive layer and of their important contribution to the stability of PSCs. This strategy is highly promising for other fullerene-based PSCs and opens a new avenue toward achieving PSCs with high PCE and excellent stability.

Triazine-based Polyelectrolyte as an Efficient Cathode Interfacial Material for Polymer Solar Cells.

A novel polyelectrolyte containing triazine (TAZ) and benzodithiophene (BDT) scaffolds with polar phosphine oxide (P═O) and quaternary ammonium ions as pendant groups, respectively, in the polymer backbone (PBTAZPOBr) was synthesized to use it as a cathode interfacial layer (CIL) for polymer solar cell (PSC) application. Owing to the high electron affinity of the TAZ unit and P═O group, PBTAZPOBr could behave as an effective electron transport material. Due to the polar quaternary ammonium and P═O groups, the interfacial dipole moment created by PBTAZPOBr substantially reduced the work function of the metal cathode to afford better energy alignment in the device, thus enabling electron extraction and reducing recombination of excitons at the photoactive layer/cathode interface. Consequently, the PSC devices based on the poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno[3,4-b]thiophene-2-carboxylate-4,6-diyl]:[6,6]-phenyl-C71-butyric acid methyl ester (PTB7:PC71BM) system with PBTAZPOBr as CIL displayed simultaneously enhanced open-circuit voltage, short-circuit current density, and fill factor, whereas the power conversion efficiency increased from 5.42% to 8.04% compared to that of the pristine Al device. The outstanding performance of PBTAZPOBr is attributed not only to the polar pendant groups of BDT unit but also to the TAZ unit linked with the P═O group of PBTAZPOBr, demonstrating that functionalized TAZ building blocks are very promising cathode interfacial materials (CIMs). The design strategy proposed in this work will be helpful to develop more efficient CIMs for high performance PSCs in the future.

Indacenodithiophene-based D-A conjugated polymers for application in polymer solar cells

The performances of polymer solar cells (PSCs) have been greatly improved in recent years mainly ascribed to the development of various donor-acceptor (D-A) conjugated photovoltaic polymers. Among the different donor monomers used for building D-A conjugated photovoltaic polymers, indacenodithiophene (IDT) has attracted much attention due to its many advantages, like high hole mobility and easy structural modification. So far, a plenty of IDT-based polymers have been proved to deliver high power conversion efficiencies through rational molecular design. In this review, we focus on structural modification strategies on IDT monomer, including attaching various side chains and importing heteroatoms substituents, and photovoltaic properties of the resultant IDT-based D-A polymers with different acceptor monomers. We hope this review could provide an important guideline for the design of high performance IDT-based PSCs.

Visibly transparent conjugated polymers based on non-alternant cyclopenta-fused emeraldicene for polymer solar cells

In this study, we synthesized two emeraldicene (EMD)-based conjugated polymers, PBTEMD and PFEMD, through polymerization of 4,7-di(thien-2-yl)benzo[c][1,2,5]thiadiazole and 9,9-bis(2-ethylhexyl)-9H-fluorene, respectively. We then blended these EMD-derived polymers (as electron-donating materials) with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) in the active layers of polymer solar cells (PSCs) and investigate their optoelectronic properties and related photovoltaic performance. To best of our knowledge, this study is the first to use EMD derivatives for PSC applications. We compared the molecular structures, absorption behavior, energy levels, thermal properties, and thermal stability of these two polymers to determine their suitability for use in PSCs. The main absorption of PFEMD was in the near-IR spectrum (600–800 nm). We observed a transparency of greater than 80% for the blend film of PFEMD having a thickness of 95 nm; the constructed device exhibited a power conversion efficiency (PCE) of 2.5% and the transparent PFEMD:PC61BM-derived device exhibited a PCE of 1.2% under AM 1.5 G irradiation (100 mW cm−2). We observed a significant improvement in thermal stability for the device incorporating the additive crosslinker TBT-N3; it retained approximately 60% of its initial PCE after accelerated heating (150 °C) for 18 h. In contrast, the PCE of the corresponding normal device decayed to 0.01% of its initial value.

Study of modification of photo active material with carbon nanostructures for polymer solar cell applications

Assorted techniques are always adapted to improve the efficiency in hybrid solar cells. One such technique is to use a combination of lower & higher band gap materials, and modified morphology of polymer: fullerene blends. The aim of all these efforts is to achieve efficient charge separation and improvement in current. In this work, the photoactive layer was modified by using two additives; (i) Multiwalled Carbon Nanotubes (MWCNT) and (ii) Graphene Nanoribbon (GNR). Basic understanding of such modifications cannot be understood till the fabrication and testing of the device. To explore the effects of such modifications on the device properties, we have studied the modified photoactive layer before the device fabrication and observed the change in optoelectronic properties under light exposure. These samples were analysed with UV–vis spectroscopy, high resolution transmission electron microscopy and photon assisted conducting atomic force microscopy (PA C-AFM). The localised current in the photoactive films with GNR additive was found significantly higher. Further, the photovoltaic device was fabricated in ambient conditions. Power conversion efficiency of the photoactive material was improved by 62% using GNR as additive, while MWCNT as additives has showed improvement by 31% in fabricated solar cell under open atmospheric conditions.

Self‐Doped, n‐Type Perylene Diimide Derivatives as Electron Transporting Layers for High‐Efficiency Polymer Solar Cells

Perylene diimide (PDI) with high electron affinities are promising candidates for applications in polymer solar cells (PSCs). In addition, the strength of π‐deficient backbones and end‐groups in an n‐type self‐dopable system strongly affects the formed end‐group‐induced electronic interactions. Herein, a series of amine/ammonium functionalized PDIs with excellent alcohol solubility are synthesized and employed as electron transporting layers (ETLs) in PSCs. The electron transfer properties of the resulting PDIs are dramatically tuned by different end‐groups and π‐deficient backbones. Notably, electron transfer is observed directly in solution in self‐doped PDIs for the first time. A significantly enhanced power conversion efficiency of 10.06% is achieved, when applying the PDIs as ETLs in PTB7‐Th:PC71BM‐based PSCs. These results demonstrate the potential of n‐type organic semiconductors with stable n‐type doping capability and facile solution processibility for future applications of energy transition devices.

Effects of Regioisomers in Fullerene Derivatives on Photovoltaic Properties of Bulk Heterojunction Solar Cells

During the last decade, bulk heterojunction (BHJ) polymer solar cells (PSCs) revealed rapid progress and achieved a power conversion efficiency (PCE) of 6-10%, owing to the development of new high-performance low-bandgap polymers as electron donors. Meanwhile, although new electron-accepting materials for PSC devices habe been explored, [70]fullerene derivatives are still prevalent as electron acceptors. An important aspect of [70]fullerene derivatives, which is always neglected in PSC applications, is that as-prepared [70]fullerene mono-adducts consist of a mixture of regioisomers due to the lower symmetry of rugby-ball shaped C70 over spherical C60. As contrasted with C60, C70 has four distinct types of [6,6]-bonds (a-, b-, e-, and k-type bonds), and thereby [70]fullerene derivatives including a prevalent, high-performance [6,6]-phenyl-C71-butyric acid methyl ester ([70]PCBM) have been employed as a regioisomer mixture in BHJ PSC devices. Considering that the miscibility with conjugated polymers and the molecular arrangement of [70]fullerene derivatives in the active layer have a large impact on charge separation and charge-transporting properties, pristine isomers of [70]fullerene derivatives rather than the isomer mixtures would yield a more desirable donor-acceptor network toward highly efficient BHJ PSCs. Indeed, the regioisomer separations of fullerene bis-adducts have been demonstrated to exhibit positive effects on BHJPSCs. In this study, the regioisomers of [70]fullerene mono-adducts have been separated for the first time to evaluate the pure isomer effect on the photovoltaic properties. To assess the substitution position effect on C70 accurately, first we designed new dihydronaphthyl-substituted [70]fullerenes with two butoxycarbonyl groups ([70]NCMA) as a simplified system. The symmetrical dihydronaphthyl group was selected as the substituent to eliminate the plausible isomers such as enantiomers and diastereomers. Then, we have further extended this strategy to separate the regioisomers of a prevalent, high-performance [70]fullerene mono-adduct acceptor, [70]PCBM, for the first time. [1] S. Kitaura, K. Kurotobi, M. Sato, Y. Takano, T. Umeyama, and H. Imahori, Chem. Commun., 48, 8550-8552 (2012). [2] R. Tao, T. Umeyama, K. Kurotobi, and H. Imahori, ACS Appl. Mater. Interface, 6, 17313-17322 (2014). [3] R. Tao, T. Umeyama, T. Higashino, T. Koganezawa, and H. Imahori, Chem. Commun., 51, 8199-8388 (2015). [4] R. Tao, T. Umeyama, T. Higashino, T. Koganezawa and H. Imahori, ACS Appl. Mater. Interfaces, 7, 16676-16685 (2015). [5] T. Umeyama, T. Miyata, A. C. Jakowetz, S. Shibata, K. Kurotobi, T. Higashino, T. Koganezawa, M. Tsujimoto, , S. Gélinas, W. Matsuda, S. Seki, R. H. Friend, and H. Imahori, Chem. Sci., in press.

Naphthalene tetracarboxylic diimide (NDI)-based polymer solar cells processed by non-halogenated solvents

Two non-fullerene acceptors, PNDIT-20 and PNDIT-16, based on naphthalenediimide (NDI) and thiophene comonomers, have been synthesized for all polymer solar cells (all-PSCs) application. The incorporation of long alkyl chains onto the NDI units endows the polymers with excellent solubility in both halogen and non-halogen solvents. Halogen-free solvents, e.g. 1,3,5-trimethylbenzene (1,3,5-TMB), 1,2,4-trimethylbenzene (1,2,4-TMB), and 1,2-dimethylbenzene (1,2-DMB), have been employed to fabricate all-PSCs based on PNDIT-20 or PNDIT-16 paired with a donor polymer PTB7-Th without use of additives or post-treatment. The devices using 1,2-DMB as the solvent demonstrated PCEs of 3.88% and 4.94% for PNDIT-20 and PNDIT-16, respectively, which are among the highest values reported for PNDIT-based all-PSCs produced using environmentally friendly solvent. The performance is superior than the control device fabricated from conventional but hazardous 1,2-dichlorobenzene (1,2-DCB). Space-charge-limited current (SCLC) measurements and active layer morphological investigation revealed that non-halogenated solvent processed devices show higher and more balanced hole and electron mobilities as well as favorable surface morphology for charge transfer. The results reported in this work suggest that non-halogenated solvents for all-PSCs processing are greatly promising for the development of high performance all-PSCs.

High‐Performance Non‐Fullerene Polymer Solar Cells Based on Fluorine Substituted Wide Bandgap Copolymers Without Extra Treatments

A new wide bandgap conjugated polymer, PFBZ, based on fluorination thienyl conjugated benzodithiophene (BDT‐2F) as a donor unit and difluorinated benzotriazole (BTz‐2F) as an acceptor unit, was synthesized for non‐fullerene polymer solar cells (PSCs) application. Compared with the analogue based on non‐fluorinated BDT unit (PBZ), PFBZ shows a lower HOMO level, a similar wide optical bandgap with a higher extinction coefficient, and a slightly higher hole mobility. As a result, without any extra treatments, the PFBZ:ITIC‐based device exhibits a higher PCE of 10.4% with Voc of 0.89 V, Jsc of 18.8 mA cm−2, and FF of 62% in comparison with the PCE of 8.0% with Voc of 0.79 V, Jsc of 17.2 mA cm−2, and FF of 59% for PBZ:ITIC‐based devices. Furthermore, the photovoltaic performance of the PFBZ: ITIC‐based devices are relatively insensitive to the thickness of the active layer and the PCE still remains 8.9% with a thickness of up to 200 nm. In addition, the PFBZ: ITIC‐based devices exhibit high tolerance to the thermal annealing, and still show a high PCE of 9.3% with annealing at 150 °C for 1 hour. These results indicate that PFBZ is a promising candidate for the large scale manufacturing and practical application of high efficient PSCs.

Surface Layering and Supersaturation for Top‐Down Nanostructural Development during Spin Coating of Polymer/Fullerene Thin Films

This study provides new evidence on a long postulated mechanism of phase separation in a polymer/fullerene mixture during spin coating for controlled nanodomains of oriented crystallization and heterojunctions that favor applications in polymer solar cells (PSCs). The simultaneous nanoscale phase separation and crystallization during spin coating of the mixture are traced using in situ grazing‐incidence small‐ and wide‐angle X‐ray scattering. Combined with the complimentary results from time‐resolved optical reflectance spectroscopy, transient stratification of the liquid film during the transition from the flow‐ to evaporation‐dominated stage of spin coating is disclosed; the vertical liquid–liquid phase separation incubates a supersaturated skin layer where fullerene aggregation and polymer crystallization occur and develop concomitantly. Shortly after the transition, the near‐surface structural development is largely pinned, leaving the solvent‐rich bottom layer to diminish via solvent diffusion and evaporation through the thickened skin layer that finally condenses into the spin‐coated film upon solvent depletion. The shear‐enhanced surface layering and supersaturation for the surface‐down nanostructural development are unexpected in all the existing structural models for PSCs. The mechanistic understanding of coupled vertical phase separation and local nanosegregation provides new insights and alternative strategy to the morphology control of spin‐cast PSC active layers in particular and various solution‐processed polymeric films in general.

Electrochemical route to fabricate porous organic polymers film and its application for polymer solar cells

A facile and controllable electrochemical polymerization of porous organic polymers (POP) film using carbazolyl triphenylethylene derivative (TPCz) as building block for the applications in polymer solar cells(PSCs) was developed. The POP film is an interlocked network film of poly-TPCz (designated as PTPCz) which has smooth surface morphology and porous nanostructures. The film can increase the work function (WF) of the anode of PSCs, the contact with the active layer, and enhance hole-extraction process. By using PEDOT:PSS/PTPCz instead of PEDOT:PSS as the anode interlayer, the optimized PSCs shows a 13% enhancement in power conversion efficiency (PCE) which is 8.54%. These results indicate the potential of electrochemical synthesized POP film as efficient interlayer for PSCs.

A novel wide bandgap conjugated polymer (2.0 eV) based on bithiazole for high efficiency polymer solar cells

An efficient wide bandgap conjugated polymer (PTZ6) based on alkoxylphenyl substituted benzodithiophene as donor unit and bithiazole as acceptor unit was developed for polymer solar cells (PSCs). The polymer exhibited a wide bandgap of 2.0eV with strong absorption in the range of 300–620nm, and a low-lying highest occupied molecular orbital (HOMO) energy level of −5.36eV. The PSCs based on PTZ6: PC71BM show a PCE of 8.1% with a Voc of 0.96V, a Jsc of 10.9mAcm−2 and a high FF of 76.7%, which is among the highest values for the fullerene PSCs based on conjugated polymer donors with bandgap near to 2.0eV. Moreover, for this blend system, the photovoltaic performance of the devices changes little when the active layer thickness increases from 90nm to 220nm. More importantly, the non-fullerene PSCs based on PTZ6: ITIC exhibit a PCE of 10.3% with a high Voc of 1.01V, which should be the best value for the non-fullerene PSCs with the Eloss less than 0.6eV to date. Our results indicate that PTZ6 is a promising wide bandgap polymer donor for the photovoltaic application in PSCs.

Naphthalene Diimide-Based Polymers Consisting of Amino Alkyl Side Groups:Three-Component One-Pot Polymerization and Their Application in Polymer Solar Cells

Naphthalene Diimide-Based Polymers Consisting of Amino Alkyl Side Groups:Three-Component One-Pot Polymerization and Their Application in Polymer Solar Cells

Design, synthesis, and structural characterization of the first dithienocyclopentacarbazole-based n-type organic semiconductor and its application in non-fullerene polymer solar cells

A novel dithienocyclopentacarbazole-containing n-type organic semiconductor (DTCC–IC) was designed and synthesized as the acceptor for non-fullerene solar cells.