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1.
Artigo em Inglês | MEDLINE | ID: mdl-33872454

RESUMO

In non-fullerene-based photovoltaic devices, it still remains unclear how excitons efficiently dissociate into free charge carriers even under a tiny driving force (tens of meV) with reduced energy loss. Here, dielectric constants of different non-fullerene-based solar cells consisting of fluorinated-thienyl benzodithiophene (BDT-2F)-based polymer PM6 as the typical donor, and a selected series of non-fullerene acceptors were precisely measured by a newly developed method. It was found that most of the non-fullerene acceptors exhibited higher dielectric constants than fullerene derivatives (PC61BM and PC71BM). The corresponding photoactive films exhibited not only higher dielectric constants but also the larger dielectric constant differences between donor and non-fullerene acceptors. These would result in lower exciton binding energy and increased charge dissociation possibility with low geminate losses. Additionally, the overlap between the emission spectrum of donor and absorption spectra of non-fullerene acceptors would allow the resonance energy transfer from donor to the acceptor in these non-fullerene-based devices, which was confirmed by investigating the emission spectra of pristine donor (and acceptor) films and corresponding blend films. Such an energy transfer process enhanced the efficient exciton diffusion, promising improved device performance. Therefore, based on the synergistic effect of higher dielectric property and energy transfer on charge separation of selected non-fullerene-based photovoltaic devices, these results provided strong hints to interpret efficient charge separation for the high device performance with a tiny driving force. Our work paves another path to elucidate the intrinsic physical working mechanism on non-fullerene organic solar cells.

2.
Adv Mater ; : e2007177, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33742493

RESUMO

The intrinsic electronic properties of donor (D) and acceptor (A) materials in coupling with morphological features dictate the output in organic solar cells (OSCs). New physical properties of intimate eutectic mixing are used in nonfullerene-acceptor-based D-A1 -A2 ternary blends to fine-tune the bulk heterojunction thin film morphology as well as their electronic properties. With enhanced thin film crystallinity and improved carrier transport, a significant JSC amplification is achieved due to the formation of eutectic fibrillar lamellae and reduced defects state density. Material wise, aligned cascading energy levels with much larger driving force, and suppressed recombination channels confirm efficient charge transfer and transport, enabling an improved power conversion efficiency (PCE) of 17.84%. These results reveal the importance of utilizing specific material interactions to control the crystalline habit in blended films to form a well-suited morphology in guiding superior performances, which is of high demand in the next episode of OSC fabrication toward 20% PCE.

3.
Biomicrofluidics ; 14(6): 061501, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33193936

RESUMO

Microstructured functional materials such as microfibers and microparticles are widely used for a myriad of applications. Precise manipulation of the functional components and structure is important for the microstructured functional materials to achieve desired functions for advanced application. This review highlights the recent progress on the controllable microfluidic fabrication of microstructured functional materials from liquid templates. First, microfluidic strategies for controllable generation of liquid templates including laminar jets and emulsion droplets are introduced. Then, strategies for fabricating microfibers and microparticles with diverse structures and advanced functions from the liquid templates are highlighted. These strategies mainly focus on precisely engineering the functional components and microstructures of the microfibers and microparticles by tailoring those of their liquid templates to achieve desired advanced functions. Finally, future development of microfluidic techniques for industrial-scale production of the microstructured functional materials is discussed.

4.
J Am Chem Soc ; 142(47): 20124-20133, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33170682

RESUMO

We designed and synthesized a series of fused-ring electron acceptors (FREAs) based on naphthalene-fused octacyclic cores end-capped by 3-(1,1-dicyanomethylene)-5,6-difluoro-1- indanone (NOICs) using a bottom-up approach. The NOIC series shares the same end groups and side chains, as well as similar fused-ring cores. The butterfly effects, arising from different methoxy positions in the starting materials, impact the design of the final FREAs, as well as their molecular packing, optical and electronic properties, charge transport, film morphology, and performance of organic solar cells. The binary-blend devices based on this NOIC series show power conversion efficiencies varying from 7.15% to 14.1%, due to the different intrinsic properties of the NOIC series, morphologies of blend films, and voltage losses of devices.

5.
Nanomaterials (Basel) ; 10(11)2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33143281

RESUMO

We study the ultrafast photoexcitation dynamics in PBDTTT-C-T (P51, poly(4,8-bis(5-(2-ethylhexyl)-thiophene-2-yl)-benzo[1,2-b:4,5-b']dithiophene-alt-alkylcarbonyl-thieno[3,4-b]thiophene)) film (~100 nm thickness) and PBDTTT-C-T:PC71BM (P51:PC71BM, phenyl-C71-butyric-acid-methyl ester) nanostructured blend (∼100 nm thickness) with/without DIO(1,8-diiodooctane) additives with sub-10 fs transient absorption (TA). It is revealed that hot-exciton dissociation and vibrational relaxation could occur in P51 with a lifetime of ~160 fs and was hardly affected by DIO. However, the introduction of DIO in P51 brings a longer lifetime of polaron pairs, which could make a contribution to photocarrier generation. In P51:PC71BM nanostructured blends, DIO could promote the Charge Transfer (CT) excitons and free charges generation with a ~5% increasement in ~100 fs. Moreover, the dissociation of CT excitons is faster with DIO, showing a ~5% growth within 1 ps. The promotion of CT excitons and free charge generation by DIO additive is closely related with active layer nanomorphology, accounting for Jsc enhancement. These results reveal the effect of DIO on carrier generation and separation, providing an effective route to improve the efficiency of nanoscale polymer solar cells.

6.
Adv Mater ; : e2003500, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33185952

RESUMO

Developing high-performance donor polymers is important for nonfullerene organic solar cells (NF-OSCs), as state-of-the-art nonfullerene acceptors can only perform well if they are coupled with a matching donor with suitable energy levels. However, there are very limited choices of donor polymers for NF-OSCs, and the most commonly used ones are polymers named PM6 and PM7, which suffer from several problems. First, the performance of these polymers (particularly PM7) relies on precise control of their molecular weights. Also, their optimal morphology is extremely sensitive to any structural modification. In this work, a family of donor polymers is developed based on a random polymerization strategy. These polymers can achieve well-controlled morphology and high-performance with a variety of chemical structures and molecular weights. The polymer donors are D-A1-D-A2-type random copolymers in which the D and A1 units are monomers originating from PM6 or PM7, while the A2 unit comprises an electron-deficient core flanked by two thiophene rings with branched alkyl chains. Consequently, multiple cases of highly efficient NF-OSCs are achieved with efficiencies between 16.0% and 17.1%. As the electron-deficient cores can be changed to many other structural units, the strategy can easily expand the choices of high-performance donor polymers for NF-OSCs.

7.
BMC Neurol ; 20(1): 394, 2020 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-33121474

RESUMO

BACKGROUND: To investigate whether the administration of intravenous propofol before endotracheal suctioning (ES) in patients with severe brain disease can reduce the sputum suction response, improve prognosis, and accelerate recovery. METHODS: A total of 208 severe brain disease patients after craniocerebral surgery were enrolled in the study. The subjects were randomly assigned to the experimental group (n = 104) and the control group (n = 104). The experimental group was given intravenous propofol (10 ml propofol with 1 ml 2% lidocaine), 0.5-1 mg/kg, before ES, while the control group was subjected to ES only. Changes in vital signs, sputum suction effect, the fluctuation range of intracranial pressure (ICP) before and after ES, choking cough response, short-term complications, length of stay, and hospitalization cost were evaluated. Additionally, the Glasgow Outcome Scale (GOS) prognosis score was obtained at 6 months after the operation. RESULTS: At the baseline, the characteristics of the two groups were comparable (P > 0.05). The increase of systolic blood pressure after ES was higher in the control group than in the experimental group (P < 0.05). The average peak value of ICP in the experimental group during the suctioning (15.57 ± 12.31 mmHg) was lower than in the control group (18.24 ± 8.99 mmHg; P < 0.05). The percentage of patients experiencing cough reaction- during suctioning in the experimental group was lower than in the control group (P < 0.05), and the fluctuation range of ICP was increased (P < 0.0001). The effect of ES was achieved in both groups. The incidence of short-term complications in the two groups was comparable (P > 0.05). At 6 months after the surgery, the GOS scores were significantly higher in the experimental than in the control group (4-5 points, 51.54% vs. 32.64%; 1-3 points, 48.46% vs. 67.36%; P < 0.05). There was no significant difference in the length of stay and hospitalization cost between the two groups. CONCLUSIONS: Propofol sedation before ES could reduce choking cough response and intracranial hypertension response. The use of propofol was safe and improved the long-term prognosis. The study was registered in the Chinese Clinical Trial Registry on May 16, 2015 (ChiCTR-IOR-15006441).

8.
Artigo em Inglês | MEDLINE | ID: mdl-33058442

RESUMO

Regulating molecular structure to optimize the active layer morphology is of considerable significance for improving the power conversion efficiencies (PCEs) in organic solar cells (OSCs). Herein, we demonstrated a simple ternary copolymerization approach to develop a terpolymer donor PM6-Tz20 by incorporating the 5,5'-dithienyl-2,2'-bithiazole (DTBTz, 20 mol%) unit into the backbone of PM6 (PM6-Tz00). This method can effectively tailor the molecular orientation and aggregation of the polymer, and then optimize the active layer morphology and the corresponding physical processes of devices, ultimately boosting FF and then PCE. Hence, the PM6-Tz20: Y6-based OSCs achieved a PCE of up to 17.1% with a significantly enhanced FF of 0.77. Using Ag (220 nm) instead of Al (100 nm) as cathode, the champion PCE was further improved to 17.6%. This work provides a simple and effective molecular design strategy to optimize the active layer morphology of OSCs for improving photovoltaic performance.

9.
Nat Commun ; 11(1): 4612, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32929082

RESUMO

Developing a high-performance donor polymer is critical for achieving efficient non-fullerene organic solar cells (OSCs). Currently, most high-efficiency OSCs are based on a donor polymer named PM6, unfortunately, whose performance is highly sensitive to its molecular weight and thus has significant batch-to-batch variations. Here we report a donor polymer (named PM1) based on a random ternary polymerization strategy that enables highly efficient non-fullerene OSCs with efficiencies reaching 17.6%. Importantly, the PM1 polymer exhibits excellent batch-to-batch reproducibility. By including 20% of a weak electron-withdrawing thiophene-thiazolothiazole (TTz) into the PM6 polymer backbone, the resulting polymer (PM1) can maintain the positive effects (such as downshifted energy level and reduced miscibility) while minimize the negative ones (including reduced temperature-dependent aggregation property). With higher performance and greater synthesis reproducibility, the PM1 polymer has the promise to become the work-horse material for the non-fullerene OSC community.

10.
Macromol Rapid Commun ; 41(21): e2000170, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32776395

RESUMO

Two wide-bandgap (WBG) conjugated polymers (PBPD-p and PBPD-m) based on phenyl-substituted benzodithiophene (BDT) with the different substitution position of the alkyl side chain and benzodithiophene-4,8-dione (BDD) units are designed and synthesized to investigate the influence of alkyl substitution position on the photovoltaic performance of polymers in polymer solar cells (PSCs). The thermogravimetric analysis, absorption spectroscopy, molecular energy level, X-ray diffraction, charge transport and photovoltaic performance of the polymers are systematically studied. Compared with PBPD-p, PBPD-m exhibits a slight blue-shift but a deeper highest occupied molecular orbital (HOMO) energy level, a tighter alkyl chain packing and a higher hole mobility. The PBPD-m-based PSCs blended with acceptor IT-4F shows a higher power conversion efficiency (PCE) of 11.95% with a high open-circuit voltage (Voc ) of 0.88 V, a short-circuit current density (Jsc ) of 19.76 mA cm-2 and a fill factor (FF) of 68.7% when compared with the PCE of 6.97% with a Voc of 0.81 V, a Jsc of 15.97 mA cm-2 and an FF of 53.9% for PBPD-p. These results suggest that it is a feasible and effective strategy to optimize photovoltaic properties of WBG polymers by changing the substitution position of alkyl side chain in PSCs.

11.
Proc Natl Acad Sci U S A ; 117(35): 21147-21154, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817532

RESUMO

Semitransparent organic photovoltaic cells (ST-OPVs) are emerging as a solution for solar energy harvesting on building facades, rooftops, and windows. However, the trade-off between power-conversion efficiency (PCE) and the average photopic transmission (APT) in color-neutral devices limits their utility as attractive, power-generating windows. A color-neutral ST-OPV is demonstrated by using a transparent indium tin oxide (ITO) anode along with a narrow energy gap nonfullerene acceptor near-infrared (NIR) absorbing cell and outcoupling (OC) coatings on the exit surface. The device exhibits PCE = 8.1 ± 0.3% and APT = 43.3 ± 1.2% that combine to achieve a light-utilization efficiency of LUE = 3.5 ± 0.1%. Commission Internationale d'eclairage chromaticity coordinates of (0.38, 0.39), a color-rendering index of 86, and a correlated color temperature of 4,143 K are obtained for simulated AM1.5 illumination transmitted through the cell. Using an ultrathin metal anode in place of ITO, we demonstrate a slightly green-tinted ST-OPV with PCE = 10.8 ± 0.5% and APT = 45.7 ± 2.1% yielding LUE = 5.0 ± 0.3% These results indicate that ST-OPVs can combine both efficiency and color neutrality in a single device.

12.
Angew Chem Int Ed Engl ; 59(45): 19835-19840, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-32666653

RESUMO

A non-conjugated polymer acceptor PF1-TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient >105  cm-1 , a high LUMO level of -3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1-TS4-based all-PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is ≈45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1-TS4-based all-PSC has good thermal stability with ≈70 % of its initial PCE retained after being stored at 85 °C for 180 h, while the IDIC16-based device only retained ≈50 % of its initial PCE when stored at 85 °C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non-conjugated thioalkyl segments.

13.
ACS Appl Mater Interfaces ; 12(31): 35120-35131, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32648440

RESUMO

This work reports on a simple and general strategy for continuous fabrication of self-propelled micromotors with photocatalytic metal-organic frameworks (MOFs) for enhanced synergistic degradation of organic contaminants. With emulsion microdroplets from microfluidics as templates, uniform porous micromotors decorated with Fe3O4@Ag nanoparticles (Fe3O4@AgNPs) at the bottom and zeolitic imidazolate framework-8@ZnO nanoparticles (ZIF-8@ZnONPs) on the surface can be synthesized. The spatial location of ZIF-8@ZnONPs and Fe3O4@AgNPs in micromotors is accurately controlled in one step via their directional migration in the confined microspace of emulsion droplets driven by interfacial energy and magnetic field. The nanoengines Fe3O4@AgNPs enable asymmetric decomposition of H2O2 for bubble-propelled motion and easy magnetic recycling of the micromotor. The porous structures of micromotors provide a large surface area, benefiting decoration of Fe3O4@AgNPs and their contact with H2O2 for promoting bubble generation and reduced micromotor weight for promoting bubble-propelled motion. The nanophotocatalysts ZIF-8@ZnONPs allow enrichment of organic contaminant molecules via adsorption for efficient photocatalytic degradation. With synergistic coupling of the photocatalysis of ZIF-8@ZnONPs and advanced oxidation of the H2O2/UV system, the micromotors with bubble-propelled motion for improved mixing can achieve enhanced degradation of organic contaminants via dual synergistic degradation mechanisms. As highlighted by degradation of rhodamine B, the micromotors exhibit the highest degradation performance as compared to control groups with a single degradation mechanism and with dual degradation mechanisms but without self-propelled motion. This simple fabrication strategy is general and can be flexibly extended to other MOF materials, which may open up new avenues for developing advanced MOF-integrated micromotors for myriad applications.

14.
Small ; 16(30): e2001942, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32602255

RESUMO

Understanding the conformation effect on molecular packing, miscibility, and photovoltaic performance is important to open a new avenue for small-molecule acceptor (SMA) design. Herein, two novel acceptor-(donor-acceptor1-donor)-acceptor (A-DA1D-A)-type asymmetric SMAs are developed, namely C-shaped BDTP-4F and S-shaped BTDTP-4F. The BDTP-4F-based polymer solar cells (PSCs) with PM6 as donor, yields a power conversion efficiency (PCE) of 15.24%, significantly higher than that of the BTDTP-4F-based device (13.12%). The better PCE for BDTP-4F-based device is mainly attributed to more balanced charge transport, weaker bimolecular recombination, and more favorable morphology. Additionally, two traditional A-D-A-type SMAs (IDTP-4F and IDTTP-4F) are also synthesized to investigate the conformation effect on morphology and device performance. Different from the device result above, here, IDTP-4F with S-shape conformation outperforms than IDTTP-4F with C-shape conformation. Importantly, it is found that for these two different types of SMA, the better performing binary blend has similar morphological characteristics. Specifically, both PM6:BDTP-4F and PM6:IDTP-4F blend exhibit perfect nanofibril network structure with proper domain size, obvious face-on orientation and enhance donor-acceptor interactions, thereby better device performance. This work indicates tuning molecular conformation plays pivotal role in morphology and device effciciency, shining a light on the molecular design of the SMAs.

15.
Soft Matter ; 16(10): 2581-2593, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32083633

RESUMO

A simple and flexible strategy based on droplet microfluidics is developed for controllable fabrication of uniform magnetic SiO2 microparticles with highly-interconnected hierarchical porous structures for enhanced water decontamination. Uniform precursor water droplets containing surfactants and homogenized fine oil droplets with a relatively high volume ratio are generated from microfluidics as templates for microparticle synthesis via hydrolysis/condensation reaction. The SiO2 microparticles possess hierarchical porous structures, containing both mesopores with size of several nanometers, and well-controlled and highly-interconnected macropores with size of hundreds of nanometers. The SiO2 microparticles synergistically integrate fast mass transfer and large functional surface area for enhanced adsorption. To demonstrate the enhanced adsorption performances for organic dyes and toxic heavy metal ions, the microparticles are respectively used for removal of methylene blue in water, and modified with thiol-groups for removal of Pb2+ ions in water. Meanwhile, the microparticles can be easily recycled by magnetic field for reuse.

16.
Chemphyschem ; 20(20): 2674-2682, 2019 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-31257670

RESUMO

To achieve high open-circuit voltage (Voc ) and low acceptor content, the molecular design of a small-molecule donor with low energy loss (Eloss ) is very important for solution-processable organic solar cells (OSCs). Herein, we designed and synthesized a new coplanar A-D-A structured organic small-molecule semiconductor with non-fused ring structure π-bridge, namely B2TPR, and applied it as donor material in OSCs. Owing to the strong electron-withdrawing effect of the end group and the coplanar π-bridge, B2TPR exhibits a low-lying highest occupied molecular orbital and strong crystallinity. Furthermore, benefiting from the coplanar molecular skeleton, the high hole mobility, balanced charge transport and reduced recombination were achieved, leading to a high fill factor (FF). The OSCs based on B2TPR : PC71 BM blend film (w/w=1 : 0.35) demonstrates a moderate power conversion efficiency (PCE) of 7.10 % with a remarkable Voc of 0.98 V and FF of 64 %, corresponding to a low fullerene content of 25.9 % and a low Eloss of 0.70 eV. These results demonstrate the great potential of small-molecule with structure of B2TPR for future low-cost organic photovoltaic applications.

17.
Chem Asian J ; 14(18): 3085-3095, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31310451

RESUMO

Over the past decade, organic solar cells (OSCs) have achieved a dramatic boost in their power conversion efficiencies from about 6 % to over 16 %. In addition to developments in device engineering, innovative photovoltaic materials, especially fluorinated donors and acceptors, have become the dominant factor for improved device performance. This minireview highlights fluorinated photovoltaic materials that enable efficient OSCs. Impressive OSCs have been obtained by developing some important molds of fluorinated donor and acceptor systems. The molecular design strategy and the matching principle of fluorinated donors and acceptors in OSCs are discussed. Finally, a concise summary and outlook are presented for advances in fluorinated materials to realize the practical application of OSCs.


Assuntos
Técnicas Eletroquímicas , Compostos Orgânicos/química , Energia Solar , Halogenação , Processos Fotoquímicos
18.
Phys Chem Chem Phys ; 21(20): 10660-10666, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31080967

RESUMO

As promising candidates for future applications in building-integrated photovoltaics, semitransparent organic solar cells (ST-OSCs) have made tremendous progress. However, power conversion efficiency (PCE) of the ST-OSCs is limited by intrinsic narrow absorption spectra concentrated in the near infrared region (NIR), weak extinction coefficient, and mismatched molecular energy levels of thin active layers. Here, an efficient ST-OSC based on a donor/acceptor electron pair of a trifluorinated polymer donor PBFTT and a tetrachlorinated acceptor IT-4Cl was fabricated. Due to halogenation, photovoltaic materials show stronger extinction coefficient, improved crystallinity and higher charge carrier mobility; PBFTT shows lower electronic energy levels, and IT-4Cl shows a red-shifted absorption spectrum. As a result, the PBFTT:IT-4Cl pair shows matched energy levels, complementary absorption spectra in the NIR region and a good blend morphology. Hence, as-cast OSCs based on PBFTT:IT-4Cl achieved a high PCE of 11.1% with a high short-circuit current density of 19.7 mA cm-2 and a high fill factor of 73.9%. Owing to the complementary absorption spectra in the NIR region, high EQE values between 600 and 830 nm and a favourable transparency window between 400 and 600 nm, while the human eye has the highest sensitivity in the yellow-green wavelength region (500-600 nm), ST-OSCs using an ultra-thin (10-20 nm) Au cathode showed high PCEs of 7.9-9.1% at a high average visible transmittance of 37.3-27.6% in the photopic region. The PCE of 9.1% is one of the highest values reported in the literature for ST-OSCs without any extra treatment and with an AVT of more than 25% in the photopic region so far.

19.
ACS Nano ; 13(4): 4686-4694, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-30892869

RESUMO

Flexible organic solar cells (OSCs) are considered one key component in wearable, intelligent electronics due to the unique capacity for highly flexible renewable energy sources. However, it is urgently required to enhance their efficiency, as it is far inferior to that of their conventional, glass-based counterparts. To boost the performance of flexible OSCs on plastic substrates, we here present a synergetic transparent electrode structure, which combines electrically conductive silver nanowires, a sol-gel-derived ZnO planarization layer, and imprinted light-trapping nanostructures. This synergetic composite electrode exhibits good properties in terms of optical transparency, electrical conductivity, mechanical flexibility, and low-temperature processability. As a result, the single-junction non-fullerene-based flexible OSCs achieve a power conversion efficiency exceeding 12% due to the synergetic interplay between broadband light trapping and suppressed charge recombination loss. Moreover, these flexible OSCs are repeatedly bendable in both inward and outward bending directions, retaining over 60% of the initial efficiency after 1000 cycles of the bending test at a 3.0 mm radius. These results convey a clear depiction of the practicality of flexible OSCs in a variety of high-performance flexible applications.

20.
Macromol Rapid Commun ; 40(1): e1800660, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30350437

RESUMO

Nonfullerene polymer solar cells (PSCs) are developed based on a fluorinated thienyl-based wide-bandgap (WBG) polymer PBBF as the electron donor and nonfullerene small molecule IDIC as the electron acceptor. PBBF exhibits a strong absorption in the range of 300-605 nm with a wide optical bandgap of 2.05 eV, which is complementary with that of IDIC. Meanwhile, it possesses a deeper highest occupied molecular orbital energy level of  -5.52 eV and a higher hole mobility of 7.3 × 10-4  cm2 V-1  s-1 compared to the nonfluorinated polymer PBDTT. The PSCs based on PBBF:IDIC without extra treatment show a power conversion efficiency (PCE) of 8.5% with a V oc of 0.95 V, a J sc of 15.3 mA cm-2 , and an FF of 58.8%, which is much higher than that of the devices based on PBDTT:IDIC (a PCE of 5.3% with a V oc of 0.88 V, a J sc of 13.7 mA cm-2 , and an FF of 43.9%). These results indicate that PBBF is a promising WBG polymer donor material for the photovoltaic applications in nonfullerene PSCs.


Assuntos
Fontes de Energia Elétrica , Fulerenos/química , Polímeros/química , Energia Solar
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