Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
1.
J Am Chem Soc ; 142(1): 392-406, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31793773

RESUMO

Polymer aggregation and crystallization behavior play a crucial role in the performance of all-polymer solar cells (all-PSCs). Gaining control over polymer self-assembly via molecular design to influence bulk-heterojunction active-layer morphology, however, remains challenging. Herein, we show a simple yet effective way to modulate the self-aggregation of the commonly used naphthalene diimide (NDI)-based acceptor polymer (N2200), by systematically replacing a certain amount of alkyl side-chains with compact bulky side-chains (CBS). Specifically, we have synthesized a series of random copolymer (PNDI-CBSx) with different molar fractions (x = 0-1) of the CBS units and have found that both solution-phase aggregation and solid-state crystallinity of these acceptor polymers are progressively suppressed with increasing x as evidenced by UV-vis absorption, photoluminescence (PL) spectroscopies, thermal analysis, and grazing incidence X-ray scattering (GIWAXS) techniques. Importantly, as compared to the highly self-aggregating N2200, photovoltaic results show that blending of more amorphous acceptor polymers with donor polymer (PBDB-T) can enable all-PSCs with significantly increased PCE (up to 8.5%). The higher short-circuit current density (Jsc) results from the smaller polymer phase-separation domain sizes as evidenced by PL quenching and resonant soft X-ray scattering (R-SoXS) analyses. Additionally, we show that the lower crystallinity of the active layer is less sensitive to the film deposition methods. Thus, the transition from spin-coating to solution coating can be easily achieved with no performance losses. On the other hand, decreasing aggregation and crystallinity of the acceptor polymer too much reduces the photovoltaic performance as the donor phase-separation domain sizes increases. The highly amorphous acceptor polymers appear to induce formation of larger donor polymer crystallites. These results highlight the importance of a balanced aggregation strength between the donor and acceptor polymers to achieve high-performance all-PSCs with optimal active layer film morphology.

2.
Angew Chem Int Ed Engl ; 59(29): 11969-11976, 2020 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-32293091

RESUMO

One-dimensional (1D) nanostructured oxides are proposed as excellent electron transport materials (ETMs) for perovskite solar cells (PSCs); however, experimental evidence is lacking. A facile hydrothermal approach was employed to grow highly oriented anatase TiO2 nanopyramid arrays and demonstrate their application in PSCs. The oriented TiO2 nanopyramid arrays afford sufficient contact area for electron extraction and increase light transmission. Moreover, the nanopyramid array/perovskite system exhibits an oriented electric field that can increase charge separation and accelerate charge transport, thereby suppressing charge recombination. The anatase TiO2 nanopyramid array-based PSCs deliver a champion power conversion efficiency of approximately 22.5 %, which is the highest power conversion efficiency reported to date for PSCs consisting of 1D ETMs. This work demonstrates that the rational design of 1D ETMs can achieve PSCs that perform as well as typical mesoscopic and planar PSCs.

3.
Nanotechnology ; 30(6): 065706, 2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30523904

RESUMO

The performance of earth abundant Cu2ZnSnS4 (CZTS) material is limited by high deficit of open circuit voltage (VOC) which is mainly due to the easy formation of CuZn antisite defects. Suppression of CuZn defects is thus inevitably required for further developments in CZTS based solar cells. We studied systematic increase of Ag doping in CZTS thin film and investigated the nanoscale electrical properties using Kelvin probe force microscopy and current sensing atomic force microscopy (CAFM) to probe CuZn defects. Crystallographic analysis indicated the successful partial substitution of Cu+ ions by large size Ag+ ions. The considerable decrease in grain boundary potential from 66.50 ± 5.44 mV to 13.50 ± 2.61 mV with Ag doping, suggesting the substantial decrease in CuZn defects. Consequently, CAFM measurement confirms the remarkable increment in minority carrier current with Ag doping and their local mobility in CZTS layer. Finally, the lower persistent photoconductivity and fast decay response of photogenerated carriers for Ag doped CZTS photodetector further validate our results. This study provides a fresh approach of controlling deleterious CuZn defects in CZTS by tuning Ag content that may guide researchers to develop next generation high-performance CZTS based solar cells.

4.
Nanotechnology ; 29(21): 215403, 2018 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-29521645

RESUMO

We present a method to synthesize CuO nanorod array/TiO2 nanocrystals bulk heterojunction (BHJ) on fluorine-tin-oxide (FTO) glass, in which single-crystalline p-type semiconductor of the CuO nanorod array is grown on the FTO glass by hydrothermal reaction and the n-type semiconductor of the TiO2 precursor is filled into the CuO nanorods to form well-organized nano-interpenetrating BHJ after air annealing. The interface charge transfer in CuO nanorod array/TiO2 heterojunction is studied by Kelvin probe force microscopy (KPFM). KPFM results demonstrate that the CuO nanorod array/TiO2 heterojunction can realize the transfer of photo-generated electrons from the CuO nanorod array to TiO2. In this work, a solar cell with the structure FTO/CuO nanoarray/TiO2/Al is successfully fabricated, which exhibits an open-circuit voltage (V oc) of 0.20 V and short-circuit current density (J sc) of 0.026 mA cm-2 under AM 1.5 illumination. KPFM studies indicate that the very low performance is caused by an undesirable interface charge transfer. The interfacial surface potential (SP) shows that the electron concentration in the CuO nanorod array changes considerably after illumination due to increased photo-generated electrons, but the change in the electron concentration in TiO2 is much less than in CuO, which indicates that the injection efficiency of the photo-generated electrons from CuO to TiO2 is not satisfactory, resulting in an undesirable J sc in the solar cell. The interface photovoltage from the KPFM measurement shows that the low V oc results from the small interfacial SP difference between CuO and TiO2 because the low injected electron concentration cannot raise the Fermi level significantly in TiO2. This conclusion agrees with the measured work function results under illumination. Hence, improvement of the interfacial electron injection is primary for the CuO nanorod array/TiO2 heterojunction solar cells.

5.
Chemistry ; 21(10): 4085-91, 2015 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-25640264

RESUMO

Two-dimensional (2D) semiconducting nanosheets have emerged as an important field of materials, owing to their unique properties and potential applications in areas ranging from electronics to catalysis. However, the controlled synthesis of ultrathin 2D nanosheets remains a great challenge, due to the lack of an intrinsic driving force for anisotropic growth. High-quality ultrathin 2D FeSe2 nanosheets with average thickness below 7 nm have been synthesized on large scale by a facile solution method, and a formation mechanism has been proposed. Due to their favorable structural features, the as-synthesized ultrathin FeSe2 nanosheets exhibit excellent electrocatalytic activity for the reduction of triiodide to iodide and low charge-transfer resistance at the electrolyte-electrode interface in dye-sensitized solar cells (DSSCs). The DSSCs with FeSe2 nanosheets as counter electrode material achieve a high power conversion efficiency of 7.53% under a simulated solar illumination of 100 mW cm(-2) (AM 1.5), which is comparable with that of Pt-based devices (7.47%).

6.
Chemistry ; 21(43): 15153-7, 2015 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-26338374

RESUMO

It is generally believed that silver or silver-based compounds are not suitable counter electrode (CE) materials for dye-sensitized solar cells (DSSCs) due to the corrosion of the I(-) /I3 (-) redox couple in electrolytes. However, Ag2 S has potential applications in DSSCs for catalyzing I3 (-) reduction reactions because of its high carrier concentration and tiny solubility product constant. In the present work, CE manufactured from Ag2 S nanocrystals ink exhibited efficient electrocatalytic activity in the reduction of I3 (-) to I(-) in DSSCs. The DSSC consisting of Ag2 S CE displayed a higher power conversion efficiency of 8.40 % than that of Pt CE (8.11 %). Moreover, the devices also showed the characteristics of fast activity onset, high multiple start/stop capability and good irradiated stability. The simple composition, easy preparation, stable chemical property, and good catalytic performance make the developed Ag2 S CE as a promising alternative to Pt CE in DSSCs.

7.
Phys Chem Chem Phys ; 17(41): 27690-7, 2015 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-26431263

RESUMO

The role of the metal-active layer interface in photogenerated recombination has been investigated using nanoscale current sensing atomic force microscopy (CS-AFM) and intensity modulated photocurrent spectroscopy (IMPS) in as-deposited, pre-annealed and post-annealed bulk heterojunction (BHJ) solar cells. Aluminum (Al) confined post-annealed BHJ solar cells exhibited a significantly improved device efficiency compared to pre-annealed BHJ solar cells having similar photocarrier harvesting ability in the active layer. The nanoscale topography and CS-AFM results indicate a uniform PCBM rich phase at the metal-active layer interface in the post-annealed cells, but PCBM segregation in the pre-annealed cells. These two different annealing processes showed different carrier dynamics revealed using IMPS under various light intensities. The IMPS results suggest reduced photo generated carrier recombination in uniform PCBM rich post-annealed BHJ solar cells. This study reveals the importance of the metal-bend interface in BHJ solar cells in order to obtain efficient charge carrier extraction for high efficiency.

8.
Phys Chem Chem Phys ; 15(18): 6856-63, 2013 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-23545704

RESUMO

A conjugated copolymer based on alternating benzo[1,2-b;3,4-b']dithiophene (BDT) donor and dodecyloxy substituted benzo[c][1,2,5]thiadiazole (ABT) acceptor units was prepared for application in organic solar cells. A power conversion efficiency (PCE) of ~3% with a short-circuit current (Jsc) of 7.63 mA cm(-2), an open-circuit voltage (Voc) of 0.71 V and a fill-factor (FF) of 53.74% was obtained under the illumination of AM 1.5 solar irradiation (100 mW cm(-2)). Photovoltaic devices and their transient properties with a blend of the copolymer and the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) at different ratios were studied using transient photovoltage (TPV), transient photocurrent (TPC) and atomic force microscopy (AFM) measurements. From the TPV and TPC measurements, the charge recombination times (τn) were found to be 21.1 µs, 12.6 µs and 10.5 µs, and the charge transport times (τd) were 1316 ns, 422 ns and 707 ns for the 1 : 0.5, 1 : 1 and 1 : 2 donor/acceptor (D/A) ratios, respectively. The 1 : 1 D/A ratio showed the shortest charge transport time (τd) and the longest charge diffusion length (Ln) according to L(n) [proportionality] √[τ(n)/τ(d)], leading to the highest device performance among the three ratios.

9.
Phys Chem Chem Phys ; 14(14): 4682-6, 2012 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-22395640

RESUMO

Nb(2)O(5) as a new electron transport layer (ETL) was used for double junction polymer solar cells. The Nb(2)O(5) ETL was prepared by spin coating a Nb(2)O(5) sol-gel solution onto the active layer of the optical front subcell. The double junction devices using Nb(2)O(5) ETL exhibit an open circuit voltage (V(oc)) of 1.30 V, which is close to the sum of the s of the individual subcells. The current density-voltage (J-V) simulation showed that the double junction device performance using Nb(2)O(5) as ETL could be significantly increased by reducing the series resistance (R(se)) and matching the current densities of the individual subcells.

10.
Phys Chem Chem Phys ; 14(29): 10168-77, 2012 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-22724125

RESUMO

Fluorescence intensity and its ratio mapping combined with time-dependent optical microscopy and atomic force microscopy (AFM) were used to understand morphology evolution of local aggregates and neighboring regions for organic solar cells. Three solvents with different boiling points including chlorobenzene (CB), 1,3-dichlorobenzene (1,3-DCB) and 1,2-dichlorobenzene (1,2-DCB) were used to engineer morphology. These solvents affected morphology evolution factors such as solvent evaporation rate, formation (e.g., growth rate, size and/or quantity) of (6,6)-phenyl-C61-butric-acid methyl ester (PCBM)-rich aggregates, and packing/ordering of poly(3-hexylthiophene) (P3HT). Three local regions (1, 2 and 3) including microscale aggregates and their surrounding areas were identified to explore the mechanism of morphology evolution. Region 1 was the PCBM-rich aggregates; region 2 was the PCBM-deficient area; and region 3 was the area composed of a relatively normal P3HT/PCBM composite beyond region 2 for each solvent. The intensity of fluorescence spectra decreased as region 1 > region 2 > region 3 in thermally annealed (140 °C, 20 min) P3HT/PCBM blend film from each solvent. The highest fluorescence intensity in region 1 was probably caused by the relatively poor phase separation where both PCBM and P3HT formed large isolated domains. The higher fluorescence intensity ratio (720 nm/650 nm) suggested a larger relative amount of PCBM molecules, supported by similar morphologies in fluorescence intensity ratio mapping compared to those in optical images. The fluorescence intensity ratio was with the order of region 1 > region 3 > region 2 in both CB and 1,3-DCB based films, but with region 1 > region 2 > region 3 for the 1,2-DCB based film. The order of effective area taken up by aggregates was CB > 1,3-DCB > 1,2-DCB in annealed (140 °C, 10 min) bulk blend films. The final solar cell performance agreed with morphology results. This work is imperative with regards to revealing the mechanism of morphology evolution in local aggregates and surrounding regions for organic photovoltaic films.

11.
Nanoscale ; 13(35): 14777-14784, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34473163

RESUMO

The underlying interface effects of sulfur hosts/polysulfides at the molecular level are of great significance to achieve advanced lithium-sulfur batteries. Herein, we systematically study the polysulfide-binding ability and the decomposition energy barrier of Li2S enabled by different kinds of nitrogen (pyridinic N, pyrrolic N and graphitic N) and phosphorus (P-O, PO and graphitic P) doping and decipher their inherent modulation effect. The doping process helps in forming a graphene-like structure and increases the micropores/mesopores, which can expose more active sites to come into contact with polysulfides. First-principles calculations reveal that the PO possesses the highest binding energies with polysulfides due to the weakening of the chemical bonds. Besides, PO as a promoter is beneficial for the free diffusion of lithium ions, and the pyridinic N and pyrrolic N can greatly reduce the kinetic barrier and catalyze the polysulfide conversion. The synergetic effects of nitrogen and phosphorus as bifunctional active centers help in achieving an in situ adsorption-diffusion-conversion process of polysulfides. Benefiting from these features, the graphene-like network achieves superior rate capability (a high reversible capacity of 954 mA h g-1 at 2C) and long-term stability (an ultralow degradation rate of 0.009% around 800 cycles at 5C). Even at a high sulfur loading of 5.6 mg cm-2, the cell can deliver an areal capacity of 4.6 mA h cm-2 at 0.2C.

12.
RSC Adv ; 10(50): 29910-29917, 2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-35518229

RESUMO

Biochar carbon YP-50 exposed to gamma radiation at 50 kGy, 100 kGy, and 150 kGy was used as an electrode for an electric double-layer capacitor. The gamma radiation affected the pore structure and pore volume of the biochar electrodes. The optimized surface morphology, pore structure, and pore volume of the biochar with an irradiation dose of 100 kGy showed outstanding specific capacitance of 246.2 F g-1 compared to the untreated biochar (115.3 F g-1). The irradiation dose of 100 kGy exhibited higher specific power and specific energy of 0.1 kW kg-1 and 34.2 W h kg-1 respectively, with a capacity retention of above 96% after 10 000 cycles at a current density of 2 A g-1. This improvement can be attributed to the decrease in average particle size, an increase in the porosity of biochar carbon. Besides, the charge transfer resistance of supercapacitor is significantly reduced from 21.7 Ω to 7.4 Ω after treating the biochar carbon with 100 kGy gamma radiation, which implies an increase in conductivity. This gamma radiation strategy to pretreat the carbon material for improving the properties of carbon materials can be promising for the development of high-performance supercapacitors for large-scale applications.

13.
ACS Appl Mater Interfaces ; 12(11): 12696-12705, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32093473

RESUMO

Mesoporous-structure perovskite solar cells (meso-PVKSCs) have been widely utilized due to the achieved high efficiency for which the TiO2 layer usually suffers from sufficient electron trap states, low electron mobility, and inavoidable catalytic activity. Herein, a mesoporous TiO2 (m-TiO2) layer is modified by tetraethylammonium p-toluenesulfonate (abbreviated as TEATS) for the first time, leading to a significant photoelectric conversion efficiency enhancement from 19.14 to 20.69% for Cs0.05MA0.12FA0.83PbI2.55Br0.45 (abbreviated as CsMAFA) meso-PVKSCs. In particular, the obtained champion open-circuit voltage (Voc) is 1.18 V, which is a record high value for meso-PVKSCs with CsMAFA triple cation mixed perovskite. A series of measurements were employed to investigate the influences of TEATS modification on the energy band structures of TiO2 as well as the CsMAFA perovskite layer atop, unveiling that TEATS modification benefits defect passivation of the TiO2 film along with a decrease in the work function of TiO2. Besides, TEATS modification helps to improve the wettability of perovskite precursors on the m-TiO2 substrate, affording improved film quality of perovskite with enhanced crystallinity and grain size. Consequently, the trap states existed in the perovskite film can be passivated, and the interfacial charge recombination is suppressed. This further benefits the improvement of the ambient stability of devices.

14.
ACS Omega ; 5(15): 8687-8696, 2020 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-32337431

RESUMO

Dye-sensitized solar cells (DSSCs) are solar energy conversion devices with high efficiency and simple fabrication procedures. Developing transparent counter electrode (CE) materials for bifacial DSSCs can address the needs of window-type building-integrated photovoltaics (BIPVs). Herein, transparent organic-inorganic hybrid composite films of molybdenum disulfide and poly(3,4-ethylenedioxythiophene) (MoS2/PEDOT) are prepared to take full advantage of the conductivity and electrocatalytic ability of the two components. MoS2 is synthesized by hydrothermal method and spin-coated to form the MoS2 layer, and then PEDOT films are electrochemically polymerized on top of the MoS2 film to form the composite CEs. The DSSC with the optimized MoS2/PEDOT composite CE shows power conversion efficiency (PCE) of 7% under front illumination and 4.82% under back illumination. Compared with the DSSC made by the PEDOT CE and the Pt CE, the DSSC fabricated by the MoS2/PEDOT composite CE improves the PCE by 10.6% and 6.4% for front illumination, respectively. It proves that the transparent MoS2/PEDOT CE owes superior conductivity and catalytic properties, and it is an excellent candidate for bifacial DSSC in the application of BIPVs.

15.
Nat Commun ; 11(1): 93, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900398

RESUMO

Lithium metal anodes have attracted extensive attention owing to their high theoretical specific capacity. However, the notorious reactivity of lithium prevents their practical applications, as evidenced by the undesired lithium dendrite growth and unstable solid electrolyte interphase formation. Here, we develop a facile, cost-effective and one-step approach to create an artificial lithium metal/electrolyte interphase by treating the lithium anode with a tin-containing electrolyte. As a result, an artificial solid electrolyte interphase composed of lithium fluoride, tin, and the tin-lithium alloy is formed, which not only ensures fast lithium-ion diffusion and suppresses lithium dendrite growth but also brings a synergistic effect of storing lithium via a reversible tin-lithium alloy formation and enabling lithium plating underneath it. With such an artificial solid electrolyte interphase, lithium symmetrical cells show outstanding plating/stripping cycles, and the full cell exhibits remarkably better cycling stability and capacity retention as well as capacity utilization at high rates compared to bare lithium.

16.
Science ; 367(6482): 1135-1140, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32139544

RESUMO

Stacking solar cells with decreasing band gaps to form tandems presents the possibility of overcoming the single-junction Shockley-Queisser limit in photovoltaics. The rapid development of solution-processed perovskites has brought perovskite single-junction efficiencies >20%. However, this process has yet to enable monolithic integration with industry-relevant textured crystalline silicon solar cells. We report tandems that combine solution-processed micrometer-thick perovskite top cells with fully textured silicon heterojunction bottom cells. To overcome the charge-collection challenges in micrometer-thick perovskites, we enhanced threefold the depletion width at the bases of silicon pyramids. Moreover, by anchoring a self-limiting passivant (1-butanethiol) on the perovskite surfaces, we enhanced the diffusion length and further suppressed phase segregation. These combined enhancements enabled an independently certified power conversion efficiency of 25.7% for perovskite-silicon tandem solar cells. These devices exhibited negligible performance loss after a 400-hour thermal stability test at 85°C and also after 400 hours under maximum power point tracking at 40°C.

17.
Chempluschem ; 84(3): 241-246, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31950766

RESUMO

If counter electrodes (CEs) could also contribute to light harvesting in dye-sensitized solar cells (DSSCs), then the power conversion efficiency (PCE) of DSSCs would be further boosted without changing the device structure. Nearly monodispersed Ag2 Se nanocrystals with a bandgap of 1.62 eV (∼765 nm) were synthesized via a one-pot process, and Ag2 Se CEs were fabricated by using a spin-coating and annealing process. Incident photon-to-current conversion efficiency and photocurrent spectra indicated that Ag2 Se CEs can generate the electricity by harvesting more visible light, which could not be absorbed by dye-sensitized photoanodes. Thus, compared to Pt CE (7.57 %), the DSSC based on Ag2 Se CE exerted a higher PCE of 8.06 %. The development of photovoltaic CEs may offer an alternative way to promote the performance and competitiveness of DSSCs.

18.
J Colloid Interface Sci ; 555: 180-186, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31377644

RESUMO

CsPbI2Br inorganic perovskite has been considered as a promising candidate for application in photovoltaic devices due to its high thermal stability and reasonable bandgap of 1.92 eV. However, CsPbI2Br perovskite is sensitive to moisture, which remarkably deteriorates the stability of CsPbI2Br perovskite solar cells under the ambient conditions. Here, by using hydrophobic poly(3-hexylthiophene) (P3HT) layer in conjunction with multi-walled carbon nanotubes (MWCNTs) as the hole transporting layer, we develop a stable and high-performance carbon electrode-based CsPbI2Br inorganic perovskite solar cell (PSC). The P3HT-MWCNTs composites not only can prevent moisture ingress but also enhance the holes extraction and transport. A conversion efficiency up to 10.01% with a stabilized efficiency of 8.85% is achieved for the champion device. In addition, the as-prepared carbon electrode-based CsPbI2Br PSC exhibits an excellent long-term stability which retains ∼85% of its initial value over 240 h under the ambient conditions (∼35% R.H.) without encapsulation.

19.
Nanoscale Res Lett ; 14(1): 325, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31620919

RESUMO

In this work, a comprehensive understanding of the relationship of photon absorption, internal electrical field, transport path, and relative kinetics on Sb2S3 photovoltaic performance has been investigated. The n-i-p planar structure for TiO2/Sb2S3/P3HT heterojunction hybrid solar cells was conducted, and the photon-to-electron processes including illumination depth, internal electric field, drift velocity and kinetic energy of charges, photo-generated electrons and hole concentration-related surface potential in Sb2S3, charge transport time, and interfacial charge recombination lifetime were studied to reveal the key factors that governed the device photocurrent. Dark J-V curves, Kelvin probe force microscope, and intensity-modulated photocurrent/photovoltage dynamics indicate that internal electric field is the main factors that affect the photocurrent when the Sb2S3 thickness is less than the hole diffusion length. However, when the Sb2S3 thickness is larger than the hole diffusion length, the inferior area in Sb2S3 for holes that cannot be diffused to P3HT would become a dominant factor affecting the photocurrent. The inferior area in Sb2S3 layer for hole collection could also affect the Voc of the device. The reduced collection of holes in P3HT, when the Sb2S3 thickness is larger than the hole diffusion length, would increase the difference between the quasi-Fermi levels of electrons and holes for a lower Voc.

20.
ACS Appl Mater Interfaces ; 11(45): 42447-42454, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31625386

RESUMO

Ag nanowires (NWs)/PEDOT:PSS composite was prepared by a facile solution-processing method and employed as anode interface in nonfullerene organic solar cells (OSCs). In the presence of a Ag NWs (5%, v/v%)/PEDOT:PSS interfacial layer, a high-power conversion efficiency up to 13.53% was achieved based on a PBDB-T-2Cl:IT-4F photoactive layer system, much higher than the efficiency of the controlled counterpart device with pristine PEDOT:PSS as anode modifier. Simultaneous enhancements in short-circuit current and fill factor were observed, in comparison to the case of the pristine PEDOT:PSS interface, due to the improved electrical conductivity of Ag NWs/PEDOT:PSS composites accompanied by the increased work function for a better matching with the indium tin oxide counter electrode, which facilitated increased charge transfer and reduced charge recombination at the anode/photoactive interface for improved device performance. The results clearly revealed that the Ag NWs/PEDOT:PSS composite interface is beneficial to improve the charge extraction and favor the realization of highly efficient nonfullerene OSCs.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA