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A dihydronaphthyl-based C60 bisadduct (NCBA) acceptor is introduce as a third component to typical PTB7: PC 71 BM binary polymer solar cells (PSCs). NCBA play bridging role between the lowest unoccupied molecular orbital (LUMO) of PTB7 and PC 71 BM and provides more routes for charge carrier transfer at the interface between PTB7 and PC 71 BM, a higher open-circuit voltage ( V OC ) realize upon addition of NCBA can be achieve relative to the neat PC 71 BM as an electron acceptor. The strong visible light absorption in the range from 350 to 700 nm of NCBA molecule compared with PC 71 BM molecule, it has the effect of apparently complementary visible light absorption compare with the binary PTB7:PC 71 BM thin films. The current density–voltage ( J - V ) characteristics dependent on incident light intensity were employed and to analyze the effect of NCBA concentration on the charge carrier recombination process of ternary PSCs. The crystallinity and surface morphology of the ternary PTB7:NCBA:PC 71 BM thin films with NCBA concentration is 15% of blend acceptor is similar to that of the binary PTB7:PC 71 BM thin films, which guarantees suitable efficient exciton dissociation and charge carrier transport. The transient photovoltage (TPV) and transient photocurrent (TPC) were measured, and the results illustrate the effect of NCBA as the third component materials in terms of higher charge carrier density and long charge carrier lifetime and weaken charge carrier recombination. [ABSTRACT FROM AUTHOR]

The solution processable electron extraction layer (EEL) is crucial for polymer solar cells (PSCs). Here, we investigated titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) as an EEL and fabricated inverted PSCs with a blend of poly(3-hexylthiophene) (P3HT) and indene-C60 bisadduct (ICBA) acting as the photoactive layer, with a structure of ITO/TIPD/P3HT:ICBA/MoO 3 /Ag. After thermal annealing treatment at 150 °C for 15 min, the PSC performances increased from 3.85% to 6.84% and they achieve stable power conversion efficiency ( PCE ), with a similar PCE compared with TiO 2 as an EEL by the vacuum evaporated method. Fourier transform infrared spectroscopy (FTIR) and ultraviolet photoelectron spectroscopy (UPS) confirmed that the TIPD decomposed and formed the Ti O bond, and the energy level of the lowest unoccupied molecular orbital and the highest occupied molecular orbital increased. The space charge limited current (SCLC) measurements further confirmed the improvement in electron collection and the transport ability using TIPD as the EEL and thermal annealing. [ABSTRACT FROM AUTHOR]

Photo-annealing treatment titanium chelate (TIPD) layer, which was the indium tin oxide (ITO) interface-modified layer, was used as a replacement for the thermal annealing treatment of TIPD. The power conversion efficiency (PCE) of photo-annealed TIPD-based polymer solar cells (PSCs) is quite low in the initial stage, but it dramatically increases following constant light illumination, and the cell achieves a saturated state after 9 min of light illumination. By employing the mixed films poly[1-(5-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)-6-methylbenzo[1,2-b:4,5-b′]dithiophen-2-yl)thiophen-2-yl)-5,7-bis(2-ethylhexyl)-3-(5-methylthiophen-2-yl)-4H,8H-benzo[1,2-c:4,5-c′]dithiophene-4,8-dione] (PBDB-TF) and 2,2′-((2 Z ,2′ Z)-(((4,4,9,9-tetrakis-(4-hexylphenyl)-4,9-dihydro-sindaceno[1,2- b :5,6- b ']-dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene)) dimalononitrile (IEICO-4F) as photoactive layers, we improved the photovoltaic performance. The enhanced photovoltaic performance of TIPD films treated with photo-annealing was explained by the increased short-circuit current density (J SC). Efficient medium- and long-wavelength light transmittance and suppression of charge recombination are beneficial for enhancing the J SC value. • Titanium chelate (TIPD) films by photo annealing treatment is efficient electron extraction layer (EEL) material. • The photo annealing treatment TIPD films achieve efficient charge transport and weak charge recombination. • The efficient medium and long wavelength light transmittance efficiency for photo annealing TIPD films. [ABSTRACT FROM AUTHOR]

Ternary blend films, obtained by introducing a third component (a second acceptor as the third component) to a binary polymer solar cell (PSC), are a promising ternary strategy because the light absorption range, surface morphology, and charge carrier transport of the photoactive layer may be optimized, as can the energy level alignment between the donor and the acceptor. In this work, acceptors such as the short-wavelength-absorption polymer N2200 and the long-wavelength-absorption small molecule FOIC were combined with the donor PBDB-T-2F to construct ternary blends. The optimized ternary PSC could achieve a power conversion efficiency (PCE) of 13.98%, which is higher than the efficiencies of binary PSCs based on PBDB-T-2F:FOIC (12.65%) and PBDB-T-2F:N2200 (9.36%). The enhanced PCE of the ternary PSC is based on the high electron mobility, balanced charge transport, optimized surface morphology and charge carrier kinetics and the extended light absorption of the ternary photoactive layer, realized by adjusting the ratio of FOIC:N2200. Our results indicate that mixing a polymer acceptor into a binary photoactive layer to form a ternary blend photoactive layer is a valuable strategy for improving photovoltaic performance. Image 1 • Ternary PSCs were fabricated with F–N2200 as third component materials. • The improvement of charge dynamics process of ternary photoactive layer by ternary strategy. • The improved photon harvesting at the donor–blend acceptor interface. [ABSTRACT FROM AUTHOR]

In this experiment, the molybdenum oxide (MoO X ) layer were fabricated by spin-coated ammonium heptamolybdate ((NH 4 ) 6 Mo 7 O 24 -4H 2 O) solution and thermal annealing treatment. The MoO X layer is shown the deeper energy level, which is more match the highest occupied molecular orbital (HOMO) energy level of the donor. The effect of the thermal annealing of the MoO X layer on hole mobility and photovoltaic performance was investigated. It was found that the 16 nm thick MoO X layer has the best hole mobility and photovoltaic performance as a HEL device. From the space charge limited current (SCLC) and time of flight (TOF) curve, the MoO X layer has shown the better hole extract and transport ability compared with polyethylenedioxy-thiophene:polystyrenesulfonate (PEDOT:PSS, Clevios Al4083) layer. The photocurrent density versus effective voltage ( J ph  −  V eff ) curve, short-circuit current ( J SC ) and open-circuit voltage ( V OC ) value dependent on incident light intensity is confirmed that the weaken charge carrier recombination of MoO X -based PSCs at the open circuit condition and short circuit condition. After prolonged light illumination (during ten days), the MoO X -based PSCs is shown the better photo-stability compared with PEDOT:PSS-based PSCs and the similar decrease ratio compared with inverted PSCs. [ABSTRACT FROM AUTHOR]

Abstract: Herein we report a study of the doping of the poly(2-methoxy-5-(30,70-dimethyloctyloxy)-1,4- phenylenevinylene) (MDMO-PPV), poly (3-oc tylthiophene) (P3OT), to the organic photovoltaic devices based on poly (3-hexylthiophene) (P3HT) and graphene derivative bulk heterojunction structure (BHJ). The addition of the donor polymers to P3HT:Graphene BJT solar cells resulted in a more broad absorption range. The interrelationships between UV–vis absorption, fill factor (FF), energy conversion efficiency (ECE) and current density have been simulated. Dependency of the open-circuit voltage (Voc) was based on different doped donors, which is due to the band structure of BHJ where the energy level difference between the highest occupied molecular orbital (HOMO) of the co-donors and the lowest occupied molecular orbital (LUMO) of the solution-processable functionalized graphene oxide (SPFGO) as acceptor was increased. The investigation indicated that the ECE of the co-donors:SPFGO BHJ solar devices with moderate doped donor amount can be influenced by the change of molecular packing structure, which can be interpreted in terms of incorporating doped donor. The XRD investigation of the complex donors/graphene BHJ solar device showed a well-organized intraplane structure with lamellae oriented normal to the substrate. In addition, The SEM investigation indicated the surface roughness morphology of the hybrid active layer film. [Copyright &y& Elsevier]