Phase diagram of P3HT:PC70BM thin films based on variable-temperature spectroscopic ellipsometry

In this article, we present the research on the influence of the composition of thin films of a blend of poly (3-hexylthiophene −2,5-diyl) - P3HT with fullerene derivatives [6,6]-phenyl-C71-butyric acid methyl ester – PC70BM and [6,6]-phenyl-C61-butyric acid methyl ester – PC60BM on their thermal transitions. The influence of molar mass (Mw) of P3HT (Mw = 65.2; 54.2 and 34.1 kDa) and PCBM (PC60BM – Mw = 911 g/mol and PC70BM – Mw = 1031 g/mol) is examined in details. The article presents significantly expanded research compared to our previous work on thermal transitions in thin films of blend P3HT (Mw = 65.2 kDa) with PC60BM. For this reason, we also compare current results with previous ones. Here, we present for the first time a phase diagram of thin films of the P3HT(Mw = 65.2 kDa):PC70BM blend using variable-temperature ellipsometry. Our research reveals the presence of characteristic temperatures of pure phases in thin films of P3HT: PCBM blends. It turns out that the cold crystallization temperature of the P3HT phase in P3HT(Mw = 65.2 kDa):PC70BM blend films is lower than corresponding temperature in P3HT(Mw = 65.2 kDa):PC60BM blend films. At the same time, the cold crystallization temperature of the PC70BM phase behaves inversely. We demonstrate also that variable-temperature spectroscopic ellipsometry is a very sensitive technique for studying thermal transitions in these thin films. In addition, we show that the entire phase diagram can be determined based on the raw ellipsometric data analysis, e.g. using a delta angle at wavelength λ = 280 nm.     

Dihydronaphthyl-based [60]fullerene bisadducts for efficient and stable polymer solar cells

Dihydronaphthyl-based [60]fullerene bisadduct derivative, NC(60)BA, was synthesized at mild temperature in high yield. NC(60)BA not only possesses a LUMO energy level 0.16 eV higher than PC(61)BM but also has amorphous nature that can overcome thermal-driven crystallization. The fabricated P3HT:NC(60)BA-based polymer solar cells exhibit superior photovoltaic performance and thermal stability compared to PC(61)BM-based devices under the same conditions.     

Large open-circuit voltage polymer solar cells by poly(3-hexylthiophene) with multi-adducts fullerenes

Polymer solar cells (PSCs) made by poly(3-hexylthiophene) (P3HT) with multi-adducts fullerenes, [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), PC61BM-bisadduct (bisPC61BM) and PC61BM-trisadduct (trisPC61BM), were reported. Electrochemistry studies indicated that PC61BM, bisPC61BM and trisPC61BM had step-up distributional lowest unoccupied molecular orbital (LUMO) energy. PSCs made by P3HT with above PC61BMs show a trend of enlarged open-circuit voltages, which is in good agreement with the energy difference between the LUMO of PC61BMs and the HOMO of P3HT. On the contrary, reduced short-circuit currents (Jsc) were observed. The investigation of photo responsibility, dynamics analysis based on photo-induced absorption of composite films, P3HT:PC61BMs and n-channel thin film field-effect transistors of PC61BMs suggested that the short polaron lifetimes and low carrier mobilities were response for reduced Jsc. All these results demonstrated that it was important to develop an electron acceptor which has both high carrier mobility, and good compatibility with the electron donor conjugated polymer for approaching high performance PSCs.     

Free Carrier Generation in Organic Photovoltaic Bulk Heterojunctions of Conjugated Polymers with Molecular Acceptors: Planar versus Spherical Acceptors

A comparative study of the photophysical performance of the prototypical fullerene derivative PC₆₁BM with a planar small‐molecule acceptor in an organic photovoltaic device is presented. The small‐molecule planar acceptor is 2‐[{7‐(9,9‐di‐n‐propyl‐9H‐fluoren‐2‐yl)benzo[c][1,2,5]thiadiazol‐4‐yl}methylene]malononitrile, termed K12. We discuss photoinduced free charge‐carrier generation and transport in blends of PC₆₁BM or K12 with poly(3‐n‐hexylthiophene) (P3HT), surveying literature results for P3HT:PC₆₁BM and presenting new results on P3HT:K12. For both systems we also review previous work on film structure and correlate the structural and photophysical results. In both cases, a disordered mixed phase is formed between P3HT and the acceptor, although the photophysical properties of this mixed phase differ markedly for PC₆₁BM and K12. In the case of PC₆₁BM the mixed phase acts as a free carrier generation region that can efficiently shuttle carriers to the pure polymer and fullerene domains. As a result, the vast majority of excitons quenched in P3HT:PC₆₁BM blends yield free carriers detected by the contactless time‐resolved microwave conductivity (TRMC) method. In contrast, approximately 85 % of the excitons quenched in P3HT:K12 do not result in free carriers over the nanosecond timescale of the TRMC experiment. We attribute this to poor electron‐transport properties in the mixed P3HT:K12 phase. We propose that the observed differences can be traced to the respective shapes of PC₆₁BM and K12: the three‐dimensional nature of the fullerene cage facilitates coupling between PC₆₁BM molecules irrespective of their relative orientation, whereas for K12 strong electronic coupling is only expected for molecules oriented with their π systems parallel to each other. Comparison between the eutectic compositions of the P3HT:PC₆₁BM and P3HT:K12 shows that the former contains enough fullerene to form a percolation pathway for electrons, whereas the latter contains a sub‐percolating volume fraction of the planar acceptor. Furthermore, the planar K12 co‐assembles with P3HT into a disordered, glassy phase that partly accounts for the poor electron‐transport properties, and may also enhance recombination due to the strong intermolecular interactions between the donor and the acceptor. The implication for the performance of organic photovoltaic devices with the two acceptors is also discussed.     

以C70衍生物为电子受体的高效聚合物固体薄膜太阳能电池

以PC[70]BM(phenyl C71-butyric acid methyl ester)取代PC[60]BM(phenyl C61-butyric acid methyl ester)作为电子受体材料,以MEH-PPV(poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene])为电子给体材料,制成了本体异质结(bulk heterojunction,BHJ)聚合物太阳能电池.MEH-PPV/PC[70]BM器件在AM1.5G(80 mW/cm2)模拟太阳光的光照条件下得到了3.42%的能量转换效率,短路电流值达到了6.07 mA/cm2,开路电压0.85 V,填充因子为53%.通过紫外可见吸收光谱和外量子效率的研究,发现PC[70]BM作为电子受体,对扩大光谱的吸收范围和增加活性层的吸收系数有明显的作用.同时比较了不同溶剂对该体系器件性能的影响.通过原子力显微镜(AFM)、光暗导I-V曲线等研究,分析了1,2-二氯苯有利于给体相和受体相的微相分离和载流子的传输的原因.     

光敏层厚度与退火温度调控对聚3-己基噻吩光电探测器性能的影响

以聚3-己基噻吩(P3HT)为给体材料,富勒烯衍生物(PC61BM)为受体材料,制备了一系列结构为ITO/PEDOT:PSS/P3HT:PC61BM/C60/Al的体异质结光电探测器.研究了120、160、180与200 nm不同光敏层厚度,100、120、130、140与150℃不同退火温度等条件对器件性能的影响,并采用原子力显微镜(AFM)对光敏层形貌进行了分析.研究发现,基于180 nm厚光敏层、150℃退火处理的器件,在-2 V的偏压下550 nm处有最大响应度,为268 mA/W,并且在470~610 nm范围内响应度都超过了200 mA/W;基于180 nm厚光敏层、120℃退火处理的器件有最大线性动态范围,为95 dB.研究表明,适当厚度的光敏层有利于提高光吸收效率与器件的光伏性能;退火处理,可以使光敏层形成均匀的互穿网络结构,进而减小空穴与电子的复合概率,提高器件的光伏性能.     

Effect of 1,8-Diiodooctane Content on the Performance of P3HT:PC61BM Bulk Heterojunction Photodetectors

A series of polymer photodetectors with device configuration of ITO/PEDOT:PSS/P₃ HT:PC₆₁ BM/C₆₀/Al were prepared by using P₃ HT as the donor material and PC₆₁ BM as the acceptor material. By regulating the content of 1,8-diiodooctane(DIO)(V/V: 1%, 3%, 5%) as a processing additive, the morphology of the active layer can be greatly improved. With C₆₀ as the hole blocking layer, the dark current density of the device can be reduced b...     

Efficient ternary blend bulk heterojunction solar cells with tunable open-circuit voltage

To explore the potential of ternary blend bulk heterojunction (BHJ) photovoltaics as a general platform for increasing the attainable performance of organic solar cells, a model system based on poly(3-hexylthiophene) (P3HT) as the donor and two soluble fullerene acceptors, phenyl-C(61)-butyric acid methyl ester (PC(61)BM) and indene-C(60) bisadduct (ICBA), was examined. In all of the solar cells, the overall ratio of polymer to fullerene was maintained at 1:1, while the composition of the fullerene component (PC(61)BM:ICBA ratio) was varied. Photovoltaic devices showed high short-circuit current densities (J(sc)) and fill factors (FF) (>0.57) at all fullerene ratios, while the open-circuit voltage (V(oc)) was found to vary from 0.61 to 0.84 V as the fraction of ICBA was increased. These results indicate that the V(oc) in ternary blend BHJ solar cells is not limited to the smallest V(oc) of the corresponding binary blend solar cells but can be varied between the extreme V(oc) values without significant effect on the J(sc) or FF. By extension, this result suggests that ternary blends provide a potentially effective route toward maximizing the attainable J(sc)V(oc) product (which is directly proportional to the solar cell efficiency) in BHJ solar cells and that with judicious selection of donor and acceptor components, solar cells with efficiencies exceeding the theoretical limits for binary blend solar cells could be possible without sacrificing the simplicity of a single active-layer processing step.     

Fullerene derivative acceptors for high performance polymer solar cells

Polymer solar cells (PSCs) are composed of a blend film of a conjugated polymer donor and a soluble fullerene derivative acceptor sandwiched between a PEDOT?:?PSS coated ITO positive electrode and a low workfunction metal negative electrode. The conjugated polymer donor and the fullerene derivative acceptor are the key photovoltaic materials for high performance PSCs. For the acceptors, although [6,6]-phenyl-C(61)-butyric acid methyl ester (PC(60)BM) and its corresponding C(70) derivative PC(70)BM are dominantly used as the acceptors in PSC at present, several series of new fullerene derivatives with higher-lying LUMO energy level and better solubility were reported in recent years for further improving the power conversion efficiency of the PSCs. In this perspective paper, we reviewed the recent research progress on the new fullerene derivative acceptors, including various PC(60)BM-like C(60) derivatives, PC(60)BM bisadduct, PC(70)BM bisadduct, indene-C(60) bisadduct and indene-C(70) bisadduct, trimetallic nitride endohedral fullerenes and other C(60) derivatives with multi side chains. The synthesis and physicochemical properties of PC(60)BM and PC(70)BM were also introduced considering the importance of the two fullerene acceptors.     

High performance low band gap polymer solar cells with a non-conventional acceptor

A novel C70 fullerene derivative was designed and synthesized by [4+2] cyclic addition reaction between indene derivative (methyl 1H-indene-3-carboxylate) and C70. The absorption and photoluminescence of H120 and its mixed films with different polymer donor materials were investigated, as well as its electrochemical property and electron mobility. It was found that H120 has 0.05 eV higher LUMO level than that of PC(70)BM. Its electron mobility reached 6.32 × 10(-4) cm(2) V(-1) s(-1), which is slightly lower than 9.55 × 10(-4) cm(2) V(-1) s(-1) of PC(70)BM. The photovoltaic devices based on P3HT, and two high efficiency low band gap polymers, PBDTTT-C and PBDTTDPP as donors, with H120 as an acceptor gave power conversion efficiencies of 4.2%, 6.0% and 6.2%, respectively.     

The preparation and properties of bulk-heterojunction organic solar cells with indole-containing fulleropyrrolidine derivatives as acceptors

Two indole-containing fullerene derivatives, N-hydrogen-2-[3-(N-2-ethylhexylindolyl)][60]fulleropyrrolidine (EHIHC60P), and N-(2-ethylhexylindolyl))-2-[3-(N-2-ethylhexylindolyl)][60]fulleropyrrolidine (DEHIC60P) were synthesized by the typical Prato reaction. The absorption spectra, electrochemical properties of the two compounds were measured. Inverted solar cells were fabricated with the structure of ITO/ZnO/poly(3-hexylthiophene) (P3HT):fullerene derivatives/MoO₃/Ag. The highest power conversion efficiencies (PCEs) of 3.32% and 3.23% were obtained for P3HT/EHIHC60P and P3HT/DEHIC60P based solar cells at the composite ratio of 1:1 after the active layers were annealed at 150 °C under inert atmosphere, with a open-circuit voltage (V_oc) of 0.66 V and 0.74 V, respectively. For comparison, the device based on P3HT/PCBM at the same conditions showed the PCE of 3.28%, with a V_oc of 0.61 V. The influence on the photovoltaic property of the fullerene derivatives, which was induced by some subtle changes in the chemical structure was compared and discussed.     

In situ current voltage measurements for optimization of a novel fullerene acceptor in bulk heterojunction photovoltaics

The evaluation of the power conversion efficiency (PCE) of new materials for organic bulk heterojunction (BHJ) photovoltaics is difficult due to the large number of processing parameters possible. An efficient procedure to determine the optimum conditions for thermal treatment of polymer‐based bulk heterojunction photovoltaic devices using in situ current‐voltage measurements is presented. The performance of a new fullerene derivative, 1,9‐dihydro‐64,65‐dihexyloxy‐1,9‐(methano[1,2] benzomethano)fullerene[60], in BHJ photovolatics with poly(3‐hexylthiophene) (P3HT) was evaluated using this methodology. The device characteristics of BHJs obtained from the in situ method were found to be in good agreement with those from BHJs annealed using a conventional process. This fullerene has similar performance to 1‐(3‐methoxycarbonyl)propyl‐1‐phenyl‐[6,6]‐methano fullerene in BHJs with P3HT after thermal annealing. For devices with thickness of 70 nm, the short circuit current was 6.24 mA/cm² with a fill factor of 0.53 and open circuit voltage of 0.65 V. The changes in the current‐voltage measurements during thermal annealing suggest that the ordering process in P3HT dominates the improvement in power conversion efficiency. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Syndiotactic Polystyrene / Fullerene Composites: Elucidation of Structural Aspect

Summary: Syndiotactic polystyrene (sPS), an attractive polymer due to its wide range of application, forms polymer-solvent intercalates with a large variety of solvent molecules ranging from liquids to solids. Recently, it has been realized that sPS intercalate prepared from SPS/naphthalene gel is more promising of making mesoporous materials. Here, the composite of sPS/fullerene have been prepared by taking advantage of sublimation of naphthalene. The different techniques as like XRD, SEM, HRTEM, FT-IR, DSC, TGA etc have been employed to characterized sPS/fullerene composite. XRD investigation shows the presence of δ form sPS in the composite. SEM and HRTEM reveal the fibrillar network with fringe like structure in presence of fullerene only and the average diameter of fibril has increased as compared to pure sPS fibrils. The conductivities of these fibrils have been increased with increasing amount of fullerene.     

Facile synthesis of a 56π-electron 1,2-dihydromethano-[60]PCBM and its application for thermally stable polymer solar cells

A facile synthesis was employed to make a 56π-electron methano-PC(61)BM with a very small 1,2-dihydromethano (CH(2)) group. This new fullerene derivative possesses high electron mobility (0.014 cm(2) V(-1) s(-1)) and higher LUMO energy level (0.15 eV) than PC(61)BM. Bulk hetero-junction devices based on using poly(3-hexylthiophene) and methano-PC(61)BM as active layer exhibited better performance and thermal stability than those using the PC(61)BM analogue.     

Triplet exciton generation in bulk-heterojunction solar cells based on endohedral fullerenes

Organic bulk-heterojunctions (BHJ) and solar cells containing the trimetallic nitride endohedral fullerene 1-[3-(2-ethyl)hexoxy carbonyl]propyl-1-phenyl-Lu(3)N@C(80) (Lu(3)N@C(80)-PCBEH) show an open circuit voltage (V(OC)) 0.3 V higher than similar devices with [6,6]-phenyl-C[61]-butyric acid methyl ester (PC(61)BM). To fully exploit the potential of this acceptor molecule with respect to the power conversion efficiency (PCE) of solar cells, the short circuit current (J(SC)) should be improved to become competitive with the state of the art solar cells. Here, we address factors influencing the J(SC) in blends containing the high voltage absorber Lu(3)N@C(80)-PCBEH in view of both photogeneration but also transport and extraction of charge carriers. We apply optical, charge carrier extraction, morphology, and spin-sensitive techniques. In blends containing Lu(3)N@C(80)-PCBEH, we found 2 times weaker photoluminescence quenching, remainders of interchain excitons, and, most remarkably, triplet excitons formed on the polymer chain, which were absent in the reference P3HT:PC(61)BM blends. We show that electron back transfer to the triplet state along with the lower exciton dissociation yield due to intramolecular charge transfer in Lu(3)N@C(80)-PCBEH are responsible for the reduced photocurrent.     

Stabilizing bicontinuous nanophase segregation in piCP-C60 donor-acceptor blends

The synthesis and thin film properties of a conjugated polymer bearing graft chains that are compatible with a fullerene, chemically modified with a similar motif, are described. The graft copolymer, obtained by nitroxide-mediated radical polymerization of a vinyl triazole onto a postfunctionalized poly(3-hexylthiophene) (P3HT) backbone, is blended with a fullerene modified with a pendant triazole functionality (TAZC60). For a given ratio of polymer:TAZC60, graft copolymer (P3HT-g-PVTAZ:TAZC60) blends exhibit substantially reduced photoluminescence compared to P3HT:TAZC60 blends, while TEM analysis reveals the graft polymer undergoes extensive mixing with the fullerene to form bicontinuous 10 nm phase domains. Graft polymer blends annealed for 1 h at 140 degrees C retain their nanometer phase separation as evidenced by TEM, UV-vis, XRD, and photoluminescence analysis, and phase purity was enhanced. In contrast, P3HT:TAZC60 blends exhibit micron-sized phase-segregated morphologies before and after annealing. The chemical similarity of the triazole functionality attached to P3HT and the fullerene leads to the formation of films with uniform, stable, nanophase morphologies. This strategy may prove a useful strategy for controlling the extent of phase segregation in electron donor and acceptor blends of pi-conjugated polymers (piCPs) and fullerenes.     

Effect of composition on the conductivity and morphology of poly(3-hexylthiophene)/gold nanoparticle composite Langmuir-Schaeffer films

Ultrathin Langmuir-Schaeffer (LS) films were fabricated from blends of regioregular poly(3-hexylthiophene) (P3HT) and highly monodispersed dodecanethiolate-capped gold nanoparticles (Au NPs) mixed in varying weight ratios. The morphology of the ultrathin films was investigated by UV-visible absorption spectroscopy, atomic force microscopy (AFM) and field-emission scanning electron microscopy (FE-SEM). The results of the structural investigations were correlated with the lateral conductivity of the films, with P3HT in its unintentionally doped state, probed by scanning electrochemical microscopy (SECM), which proved to be a very sensitive technique. Control over the P3HT/Au NP ratio led to remarkable changes in the morphology and lateral conductivity of the films. Inclusion of Au NPs into P3HT was found to influence the ordering of P3HT, which ultimately determined the macroscopic charge transport characteristics of the films. Composite films with ca. 33% by weight of Au NPs were found to be the most ordered and exhibited the highest conductivity, substantially higher than P3HT alone. To provide insight into the film formation process, LS composite films comprising equal quantities of P3HT and Au NPs (by weight) were transferred at several surface pressures and investigated by SECM, AFM and FE-SEM.     

Effect of TiO2 nanoparticles on self-assembly behaviors and optical and photovoltaic properties of the P3HT-b-P2VP block copolymer

An ordered nanostructure can be created from the hybrid materials of self-assembly poly(3-hexyl thiophene-b-2-vinyl pyridine) and nicotinic acid-modified titanium dioxide nanoparticles (P3HT-b-P2VP/TiO(2)). TEM and XRD analyses reveal that the TiO(2) nanoparticles (NPs) are preferentially confined in the P2VP domain of P3HT-b-P2VP whereas TiO(2) NPs interact with either pure P3HT or a blend of P3HT and P2VP to produce microsized phase segregation. The morphologies of lamellar and cylindrical structures are disturbed when the loading of TiO(2) NPs is 40 wt % or higher. Cylindrical P3HT-b-P2VP/TiO(2) exhibits a small blue shift in absorption and photoluminescence spectra with increasing TiO(2) loading as compared to P3HT/TiO(2). The NPs cause a slightly misaligned P3HT domain in the copolymer. Furthermore, the PL quenching of P3HT-b-P2VP/TiO(2) becomes very large as a result of efficient charge separation in the ordered nanodomain at 16 nm. Solar cells fabricated from self-assembly P3HT-b-P2VP/TiO(2) hybrid materials exhibit a >30 fold improvement in power conversion efficiency as compared to the corresponding 0.3P3HT-0.7P2VP/TiO(2) polymer blend hybrid. This study paves the way for the further development of high-efficiency polymer-inorganic nanoparticle hybrid solar cells using a self-assembled block copolymer.     

Enhanced properties of photovoltaic devices tailored with novel supramolecular structures based on reduced graphene oxide nanosheets grafted/functionalized with thiophenic materials

For verifying the influence of donor–acceptor supramolecules on photovoltaic properties, different hybrids were designed and used in organic solar cells. In this respect, reduced graphene oxide (rGO) was functionalization with 2‐thiophene acetic acid (rGO‐f‐TAA) and grafted with poly(3‐dodecylthiophene) (rGO‐g‐PDDT) and poly(3‐thiophene ethanol) (rGO‐g‐PTEt) to manipulate orientation of poly(3‐hexylthiophene) (P3HT) assemblies. Face‐on, edge‐on, and flat‐on orientations were detected for assembled P3HTs on rGO and its functionalized and grafted derivatives, respectively. Alteration of P3HT orientation from face‐on to flat‐on enhanced current density (J _sc), fill factor (FF), and power conversion efficiency (PCE) and thus J _sc = 7.11 mA cm^?2, FF = 47%, and PCE = 2.14% were acquired. By adding phenyl‐C71‐butyric acid methyl ester (PC71BM) to active layers composed of pre‐designed P3HT/rGO, P3HT/rGO‐f‐TAA, P3HT/rGO‐g‐PDDT, and P3HT/rGO‐g‐PTEt hybrids, photovoltaic characteristics further improved, demonstrating that supramolecules appropriately mediated in P3HT:PC71BM solar cells. Phase separation was more intensified in best‐performing photovoltaic systems. Larger P3HT crystals assembled onto grafted rGOs (95–143 nm) may have acted as convenient templates for the larger and more intensified phase separation in P3HT:PCBM films. The best performances were reached for P3HT:P3HT/rGO‐g‐PDDT:PCBM (J _sc = 9.45 mA cm^?2, FF = 54%, and PCE = 3.16%) and P3HT:P3HT/rGO‐g‐PTEt:PCBM (J _sc = 9.32 mA cm^?2, FF = 53%, and PCE = 3.11%) photovoltaic systems. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 1877–1889     

Compositional dependence of the open-circuit voltage in ternary blend bulk heterojunction solar cells based on two donor polymers

Ternary blend bulk heterojunction (BHJ) solar cells containing as donor polymers two P3HT analogues, high-band-gap poly(3-hexylthiophene-co-3-(2-ethylhexyl)thiophene) (P3HT(75)-co-EHT(25)) and low-band-gap poly(3-hexylthiophene-thiophene-diketopyrrolopyrrole) (P3HTT-DPP-10%), with phenyl-C(61)-butyric acid methyl ester (PC(61)BM) as an acceptor were studied. When the ratio of the three components was varied, the open-circuit voltage (V(oc)) increased as the amount of P3HT(75)-co-EHT(25) increased. The dependence of V(oc) on the polymer composition for the ternary blend regime was linear when the overall polymer:fullerene ratio was optimized for each polymer:polymer ratio. Also, the short-circuit current densities (J(sc)) for the ternary blends were bettter than those of the binary blends because of complementary polymer absorption, as verified using external quantum efficiency measurements. High fill factors (FF) (>0.59) were achieved in all cases and are attributed to high charge-carrier mobilities in the ternary blends. As a result of the intermediate V(oc), increased J(sc) and high FF, the ternary blend BHJ solar cells showed power conversion efficiencies of up to 5.51%, exceeding those of the corresponding binary blends (3.16 and 5.07%). Importantly, this work shows that upon optimization of the overall polymer:fullerene ratio at each polymer:polymer ratio, high FF, regular variations in V(oc), and enhanced J(sc) are possible throughout the ternary blend composition regime. This adds to the growing evidence that the use of ternary blends is a general and effective strategy for producing efficient organic photovoltaics manufactured in a single active-layer processing step.