Showing papers on "Polymer solar cell published in 2013"
TL;DR: It is shown that perovskite absorbers can function at the highest efficiencies in simplified device architectures, without the need for complex nanostructures.
Abstract: Many different photovoltaic technologies are being developed for large-scale solar energy conversion. The wafer-based first-generation photovoltaic devices have been followed by thin-film solid semiconductor absorber layers sandwiched between two charge-selective contacts and nanostructured (or mesostructured) solar cells that rely on a distributed heterojunction to generate charge and to transport positive and negative charges in spatially separated phases. Although many materials have been used in nanostructured devices, the goal of attaining high-efficiency thin-film solar cells in such a way has yet to be achieved. Organometal halide perovskites have recently emerged as a promising material for high-efficiency nanostructured devices. Here we show that nanostructuring is not necessary to achieve high efficiencies with this material: a simple planar heterojunction solar cell incorporating vapour-deposited perovskite as the absorbing layer can have solar-to-electrical power conversion efficiencies of over 15 per cent (as measured under simulated full sunlight). This demonstrates that perovskite absorbers can function at the highest efficiencies in simplified device architectures, without the need for complex nanostructures.
7,018 citations
TL;DR: The development of a high-performance low bandgap polymer that enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions, which is the first certified polymer solar cell efficiency over 10%.
Abstract: An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-performance low bandgap polymer (bandgap 60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions (25 °C, 1,000 Wm(-2), IEC 60904-3 global), which is the first certified polymer solar cell efficiency over 10%.
2,708 citations
TL;DR: In this paper, a layered sandwich-type architecture is proposed for next-generation dye-sensitized solar cells, which consists of a bicontinuous three-dimensional nanocomposite of mesoporous (mp)-TiO2,w ith CH 3NH3PbII3 perovskite as light harvester, as well as a polymeric hole conductor.
Abstract: Inorganic‐organic hybrid structures have become innovative alternatives for next-generation dye-sensitized solar cells, because they combine the advantages of both systems. Here, we introduce a layered sandwich-type architecture, the core of which comprises a bicontinuous three-dimensional nanocomposite of mesoporous (mp)-TiO2 ,w ith CH 3NH3PbI3 perovskite as light harvester, as well as a polymeric hole conductor. This platform creates new opportunities for the development of low-cost, solution-processed, high-efficiency solar cells. The use of a polymeric hole conductor, especially poly-triarylamine, substantially improves the open-circuit voltage V oc and fill factor of the cells. Solar cells based on these inorganic‐organic hybrids exhibit a short-circuit current density Jsc of 16.5 mA cm 22 , Voc of 0.997 V and fill factor of 0.727, yielding a power conversion efficiency of 12.0% under standard AM 1.5 conditions.
2,461 citations
TL;DR: All-solid-state donor/acceptor planar-heterojunction (PHJ) hybrid solar cells are constructed and their excellent performance measured.
Abstract: All-solid-state donor/acceptor planar-heterojunction (PHJ) hybrid solar cells are constructed and their excellent performance measured. The deposition of a thin C60 fullerene or fullerene-derivative (acceptor) layer in vacuum on a CH3 NH3 PbI3 perovskite (donor) layer creates a hybrid PHJ that displays the photovoltaic effect. Such heterojunctions are shown to be suitable for the development of newly structured, hybrid, efficient solar cells.
1,327 citations
TL;DR: Inverted polymer solar cells with the ZnO-C60 cathode display markedly improved power conversion efficiency compared to those with a pristine ZNO cathode, especially when the active layer includes the low-bandgap polymer PTB7-Th.
Abstract: Modification of a ZnO cathode by doping it with a hydroxyl-containing derivative - giving a ZnO-C60 cathode - provides a fullerene-derivative-rich surface and enhanced electron conduction. Inverted polymer solar cells with the ZnO-C60 cathode display markedly improved power conversion efficiency compared to those with a pristine ZnO cathode, especially when the active layer includes the low-bandgap polymer PTB7-Th.
1,099 citations
TL;DR: A review of roll-to-roll (R2R) compatible applications for thin-film transistors can be found in this article, where the current status of R2R application within some of the existing research fields such as organic photovoltaics, organic thin film transistors, light-emitting diodes, polymer electrolyte membrane fuel cells and electrochromic devices.
Abstract: With the prospect of extremely fast manufacture of very low cost devices, organic electronics prepared by thin film processing techniques that are compatible with roll-to-roll (R2R) methods are presently receiving an increasing interest. Several technologies using organic thin films are at the point, where transfer from the laboratory to a more production-oriented environment is within reach. In this review, we aim at giving an overview of some of the R2R-compatible techniques that can be used in such a transfer, as well the current status of R2R application within some of the existing research fields such as organic photovoltaics, organic thin film transistors, light-emitting diodes, polymer electrolyte membrane fuel cells, and electrochromic devices. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
936 citations
TL;DR: The basic working principles and the state of the art device design of bulk heterojunction solar cells are reviewed and the importance of high power conversion efficiencies for the commercial exploitation is outlined and different efficiency models for bulk heterovoltaic cells are discussed.
923 citations
TL;DR: In this paper, the authors attributed the close-packed and highly ordered structure of the polymers PTPD3T and PBT13T, which leads to efficient charge extraction and suppressed recombination.
Abstract: New designs of donor polymers yield organic solar cells with fill factors approaching 80%, significantly higher than those of conventional cells. This enhanced performance is attributed to the close-packed and highly ordered structure of the polymers PTPD3T and PBT13T, which leads to efficient charge extraction and suppressed recombination.
867 citations
TL;DR: Analysis of the current-voltage (J-V) characteristics at various light intensities provides information on the different recombination mechanisms in the BHJ solar cells with different thicknesses of the Ca layer, revealing that the J-V curves are dominated by first-order recombination from the short-circuit condition to the maximum power point and evolve to bimolecular recombination in the range of voltage in the optimized device with a Ca thickness of 20 nm.
Abstract: Solution-processed small-molecule p-DTS(FBTTh2)2:PC71BM bulk heterojunction (BHJ) solar cells with power conversion efficiency of 8.01% are demonstrated. The fill factor (FF) is sensitive to the thickness of a calcium layer between the BHJ layer and the Al cathode; for 20 nm Ca thickness, the FF is 73%, the highest value reported for an organic solar cell. The maximum external quantum efficiency exceeds 80%. After correcting for the total absorption in the cell through normal incidence reflectance measurements, the internal quantum efficiency approaches 100% in the spectral range of 600–650 nm and well over 80% across the entire spectral range from 400 to 700 nm. Analysis of the current–voltage (J–V) characteristics at various light intensities provides information on the different recombination mechanisms in the BHJ solar cells with different thicknesses of the Ca layer. Our analysis reveals that the J–V curves are dominated by first-order recombination from the short-circuit condition to the maximum pow...
790 citations
TL;DR: In this article, a single core-shell p-i-n junction GaAs nanowire solar cell grown on a silicon substrate was shown to achieve a short-circuit current of 180 mA cm-2 at 1 sun illumination, more than one order of magnitude higher than that predicted from the Lambert-Beer law.
Abstract: Light management is of great importance in photovoltaic cells, as it determines the fraction of incident light entering the device. An optimal p–n junction combined with optimal light absorption can lead to a solar cell efficiency above the Shockley–Queisser limit. Here, we show how this is possible by studying photocurrent generation for a single core–shell p–i–n junction GaAs nanowire solar cell grown on a silicon substrate. At 1 sun illumination, a short-circuit current of 180 mA cm –2 is obtained, which is more than one order of magnitude higher than that predicted from the Lambert–Beer law. The enhanced light absorption is shown to be due to a light-concentrating property of the standing nanowire, as shown by photocurrent maps of the device. The results imply new limits for the maximum efficiency obtainable with III–V based nanowire solar cells under 1 sun illumination.
756 citations
TL;DR: In this article, the influence of the improved state-of-the-art parameters on the limiting efficiency for crystalline silicon solar cells under 1-sun illumination at 25°C, by following the narrow-base approximation to model ideal solar cells was analyzed.
Abstract: Recently, several parameters relevant for modeling crystalline silicon solar cells were improved or revised, e.g., the international standard solar spectrum or properties of silicon such as the intrinsic recombination rate and the intrinsic carrier concentration. In this study, we analyzed the influence of these improved state-of-the-art parameters on the limiting efficiency for crystalline silicon solar cells under 1-sun illumination at 25°C, by following the narrow-base approximation to model ideal solar cells. We also considered bandgap narrowing, which was not addressed so far with respect to efficiency limitation. The new calculations that are presented in this study result in a maximum theoretical efficiency of 29.43% for a 110-μm-thick solar cell made of undoped silicon. A systematic calculation of the I-V parameters as a function of the doping concentration and the cell thickness together with an analysis of the loss current at maximum power point provides further insight into the intrinsic limitations of silicon solar cells.
TL;DR: In this article, a depleted hole conductor free CH3NH3PbI3/TiO2 heterojunction solar cell using a thick CH3NHPbII3 film was presented, which formed large crystals which function simultaneously as light harvesting and hole transport materials.
Abstract: Lead halide perovskite is an excellent candidate for use as a light harvester in solar cells. Our work presents a depleted hole conductor free CH3NH3PbI3/TiO2 heterojunction solar cell using a thick CH3NH3PbI3 film. The CH3NH3PbI3 formed large crystals which function simultaneously as light harvesters and as hole transport materials. We performed capacitance voltage measurements, which show a depletion region which extends to both n and p sides. The built-in field of the depletion region assists in the charge separation and suppresses the back reaction of electrons from the TiO2 film to the CH3NH3PbI3 film. This depleted hole conductor free CH3NH3PbI3/TiO2 heterojunction solar cell provides a power conversion efficiency of 8% with a current density of 18.8 mA cm−2, the highest efficiency achieved to date for perovskite based solar cells without a hole conductor.
TL;DR: In this paper, a review of conjugated polymers with 1D and 2D topological structures is presented, and a design approach for the alternating donor-acceptor (D-A) copolymers is proposed.
TL;DR: It is shown that replacing branched side chains by linear ones in the BDT motifs induces a critical change in polymer self-assembly and backbone orientation in thin films that correlates with a dramatic drop in solar cell efficiency, making PBDTTPD one of the best polymer donors for use in the high-band-gap cell of tandem solar cells.
Abstract: While varying the size and branching of solubilizing side chains in π-conjugated polymers impacts their self-assembling properties in thin-film devices, these structural changes remain difficult to anticipate. This report emphasizes the determining role that linear side-chain substituents play in poly(benzo[1,2-b:4,5-b′]dithiophene–thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymers for bulk heterojunction (BHJ) solar cell applications. We show that replacing branched side chains by linear ones in the BDT motifs induces a critical change in polymer self-assembly and backbone orientation in thin films that correlates with a dramatic drop in solar cell efficiency. In contrast, we show that for polymers with branched alkyl-substituted BDT motifs, controlling the number of aliphatic carbons in the linear N-alkyl-substituted TPD motifs is a major contributor to improved material performance. With this approach, PBDTTPD polymers were found to reach power conversion efficiencies of 8.5% and open-circuit voltages ...
TL;DR: In this paper, a review of polymer donor-polymer acceptor (all polymer) BHJ OPVs is presented, highlighting the initial breakthroughs and recent progress in the development of polymer acceptor materials.
TL;DR: This work directly targets the interfacial physics of an efficient low-bandgap polymer/PC(60)BM system and rationalizes these findings in terms of a higher degree of delocalization of the hot CTSs with respect to the relaxed ones, which enhances the probability of charge dissociation in the first 200 fs.
Abstract: The standard picture of photovoltaic conversion in all-organic bulk heterojunction solar cells predicts that the initial excitation dissociates at the donor/acceptor interface after thermalization. Accordingly, on above-gap excitation, the excess photon energy is quickly lost by internal dissipation. Here we directly target the interfacial physics of an efficient low-bandgap polymer/PC(60)BM system. Exciton splitting occurs within the first 50 fs, creating both interfacial charge transfer states (CTSs) and polaron species. On high-energy excitation, higher-lying singlet states convert into hot interfacial CTSs that effectively contribute to free-polaron generation. We rationalize these findings in terms of a higher degree of delocalization of the hot CTSs with respect to the relaxed ones, which enhances the probability of charge dissociation in the first 200 fs. Thus, the hot CTS dissociation produces an overall increase in the charge generation yield.
TL;DR: Results strongly suggest solution-processed small molecular materials are excellent candidates for organic solar cells, using single junction and double junction tandem solar cells.
Abstract: A two-dimensional conjugated small molecule (SMPV1) was designed and synthesized for high performance solution-processed organic solar cells. This study explores the photovoltaic properties of this molecule as a donor, with a fullerene derivative as an acceptor, using solution processing in single junction and double junction tandem solar cells. The single junction solar cells based on SMPV1 exhibited a certified power conversion efficiency of 8.02% under AM 1.5 G irradiation (100 mW cm−2). A homo-tandem solar cell based on SMPV1 was constructed with a novel interlayer (or tunnel junction) consisting of bilayer conjugated polyelectrolyte, demonstrating an unprecedented PCE of 10.1%. These results strongly suggest solution-processed small molecular materials are excellent candidates for organic solar cells.
TL;DR: When mixed Ag and Au nanoparticles are incorporated into the anode buffer layer, dual nanoparticles show superior behavior on enhancing light absorption in comparison with single nanoparticles, which led to the realization of a polymer solar cell with a power conversion efficiency of 8.67%, accounting for a 20% enhancement.
Abstract: This article describes a cooperative plasmonic effect on improving the performance of polymer bulk heterojunction solar cells. When mixed Ag and Au nanoparticles are incorporated into the anode buffer layer, dual nanoparticles show superior behavior on enhancing light absorption in comparison with single nanoparticles, which led to the realization of a polymer solar cell with a power conversion efficiency of 8.67%, accounting for a 20% enhancement. The cooperative plasmonic effect aroused from dual resonance enhancement of two different nanoparticles. The idea was further unraveled by comparing Au nanorods with Au nanoparticles for solar cell application. Detailed studies shed light into the influence of plasmonic nanostructures on exciton generation, dissociation, and charge recombination and transport inside thin film devices.
TL;DR: In this paper, the authors review the latest on geminate and nongeminate recombination in organic solar cells and discuss the key loss mechanisms in charge carrier recombination, which is one of the most promising alternative energy sources because of their ease of processing and their potential to be produced using large scale techniques such as roll-to-roll, newspaper style, coating.
TL;DR: The disclosed "fluorine" impact not only explains the efficiency increase from 4% of PBnDT-DTBT (0F) to 7% with PBn DT-DTffBT (2F) but also suggests fluorine substitution should be generally considered in the future design of new polymers.
Abstract: Three structurally identical polymers, except for the number of fluorine substitutions (0, 1, or 2) on the repeat unit (BnDT-DTBT), are investigated in detail, to further understand the impact of these fluorine atoms on open circuit voltage (Voc), short circuit current (Jsc), and fill factor (FF) of related solar cells. While the enhanced Voc can be ascribed to a lower HOMO level of the polymer by adding more fluorine substituents, the improvement in Jsc and FF are likely due to suppressed charge recombination. While the reduced bimolecular recombination with raising fluorine concentration is confirmed by variable light intensity studies, a plausibly suppressed geminate recombination is implied by the significantly increased change of dipole moment between the ground and excited states (Δμge) for these polymers as the number of fluorine substituents increases. Moreover, the 2F polymer (PBnDT-DTffBT) exhibits significantly more scattering in the in-plane lamellar stacking and out-of-plane π–π stacking dire...
TL;DR: T tandem and triple-junction polymer solar cells with power conversion efficiencies of 8.9% and 9.6% are demonstrated that use a newly designed, high molecular weight, small band gap semiconducting polymer and a matching wide band gap polymer.
Abstract: We demonstrate tandem and triple-junction polymer solar cells with power conversion efficiencies of 8.9% and 9.6% that use a newly designed, high molecular weight, small band gap semiconducting polymer and a matching wide band gap polymer.
[...]
TL;DR: Recent work to image and control nanostructure in polymer-based solar cells is reviewed, and very recent progress is described using the unique properties of organic semiconductors to develop strategies that may allow the Shockley–Queisser limit to be broken in a simple photovoltaic cell.
Abstract: This article reviews the motivations for developing polymer-based photovoltaics and describes some of the material systems used. Current challenges are identified, and some recent developments in the field are outlined. In particular, recent work to image and control nanostructure in polymer-based solar cells is reviewed, and very recent progress is described using the unique properties of organic semiconductors to develop strategies that may allow the Shockley–Queisser limit to be broken in a simple photovoltaic cell.
TL;DR: In this article, the surface plasmon resonance effect of carbon-dot-supported silver nanoparticles (CD-Ag nanoparticles) was used as reducing agent and template to fabricate solution-processable polymer light-emitting diodes and polymer solar cells.
Abstract: The coupling of surface plasmons and excitons in organic materials can improve the performance of organic optoelectronic devices. Here, we prepare carbon-dot-supported silver nanoparticles (CD–Ag nanoparticles) using the carbon dots both as a reducing agent and a template to fabricate solution-processable polymer light-emitting diodes and polymer solar cells. The surface plasmon resonance effect of CD–Ag nanoparticles allows significant radiative emission and additional light absorption, leading to remarkably enhanced current efficiency of 27.16 cd A−1 and a luminous efficiency of 18.54 lm W−1 in polymer light-emitting diodes as well as a power conversion efficiency of 8.31% and an internal quantum efficiency of 99% in polymer solar cells compared with control devices (current efficiency = 11.65 cd A−1 and luminous efficiency = 6.33 lm W−1 in polymer light-emitting diodes; power conversion efficiency = 7.53% and internal quantum efficiency = 91% in polymer solar cells). These results demonstrate that CD–Ag nanoparticles constitute a versatile and effective route for achieving high-performance polymer optoelectronic devices. The coupling of surface plasmons and excitons in organic materials can improve the performance of organic optoelectronic devices. Carbon-dot-supported silver nanoparticles have now been used to improve the efficiency of polymer light-emitting diodes and polymer solar cells.
TL;DR: A significant enhancement of efficiency in thieno[3,4-b]-thiophene/benzodithiophene:[6,6]-phenyl C71-butyric acid methyl ester (PTB7:PC70 BM) solar cells can be achieved by methanol treatment.
Abstract: A significant enhancement of efficiency in thieno[3,4-b]-thiophene/benzodithiophene:[6,6]-phenyl C71-butyric acid methyl ester (PTB7:PC70 BM) solar cells can be achieved by methanol treatment. The effects of methanol treatment are shown in an improvement of built-in voltage, a decrease in series resistance, an enhanced charge-transport property, an accelerated and enlarged charge extraction, and a reduced charge recombination, which induce a simultaneous enhancement in open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) in the devices.
TL;DR: In this article, a detailed characterization of solution-derived nickel (II) oxide (NiO) hole-transporting layer (HTL) films and their application in high efficiency organic photovoltaic (OPV) cells is reported.
Abstract: The detailed characterization of solution-derived nickel (II) oxide (NiO) hole-transporting layer (HTL) films and their application in high efficiency organic photovoltaic (OPV) cells is reported. The NiO precursor solution is examined in situ to determine the chemical species present. Coordination complexes of monoethanolamine (MEA) with Ni in ethanol thermally decompose to form non-stoichiometric NiO. Specifically, the [Ni(MEA)2(OAc)]+ ion is found to be the most prevalent species in the precursor solution. The defect-induced Ni3+ ion, which is present in non-stoichiometric NiO and signifies the p-type conduction of NiO, as well as the dipolar nickel oxyhydroxide (NiOOH) species are confirmed using X-ray photoelectron spectroscopy. Bulk heterojunction (BHJ) solar cells with a polymer/fullerene photoactive layer blend composed of poly-dithienogermole-thienopyrrolodione (pDTG-TPD) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) are fabricated using these solution-processed NiO films. The resulting devices show an average power conversion efficiency (PCE) of 7.8%, which is a 15% improvement over devices utilizing a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL. The enhancement is due to the optical resonance in the solar cell and the hydrophobicity of NiO, which promotes a more homogeneous donor/acceptor morphology in the active layer at the NiO/BHJ interface. Finally, devices incorporating NiO as a HTL are more stable in air than devices using PEDOT:PSS.
TL;DR: Polymer tandem solar cells with 10.2% power conversion efficiency are demonstrated via stacking two PDTP-DFBT:PC₇₁ BM bulk heterojunctions, connected by MoO₃/PEDOT:PSS/ZnO as an interconnecting layer.
Abstract: Polymer tandem solar cells with 102% power conversion efficiency are demonstrated via stacking two PDTP-DFBT:PC₇₁ BM bulk heterojunctions, connected by MoO₃/PEDOT:PSS/ZnO as an interconnecting layer The tandem solar cells increase the power conversion efficiency of the PDTP-DFBT:PC₇₁ BM system from 81% to 102%, successfully demonstrating polymer tandem solar cells with identical sub-cells of double-digit efficiency
TL;DR: In this article, a two-step deposition technique was used for preparing CH3NH3PbI3 perovskite solar cells using ZrO2 and TiO2 as a mesoporous layer, achieving an efficiency of 10.8% and 9.5% under 1000 W m−2 illumination.
Abstract: A two-step deposition technique is used for preparing CH3NH3PbI3 perovskite solar cells. Using ZrO2 and TiO2 as a mesoporous layer, we obtain an efficiency of 10.8% and 9.5%, respectively, under 1000 W m−2 illumination. The ZrO2 based solar cell shows higher photovoltage and longer electron lifetime than the TiO2 based solar cell.
TL;DR: In this article, the authors examined the device characteristics of BHJ solar cells based on poly(di(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-co-octylthieno[3,4-c]pyrrole-4,6-dione) and found that thermal annealing drastically reduced the concentration of PCBM in the mixed regions.
Abstract: Most optimized donor-acceptor (D-A) polymer bulk heterojunction (BHJ) solar cells have active layers too thin to absorb greater than ∼80% of incident photons with energies above the polymer's band gap. If the thickness of these devices could be increased without sacrificing internal quantum efficiency, the device power conversion efficiency (PCE) could be significantly enhanced. We examine the device characteristics of BHJ solar cells based on poly(di(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-co-octylthieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) with 7.3% PCE and find that bimolecular recombination limits the active layer thickness of these devices. Thermal annealing does not mitigate these bimolecular recombination losses and drastically decreases the PCE of PBDTTPD BHJ solar cells. We characterize the morphology of these BHJs before and after thermal annealing and determine that thermal annealing drastically reduces the concentration of PCBM in the mixed regions, which consist of PCBM dispersed in the amorphous portions of PBDTTPD. Decreasing the concentration of PCBM may reduce the number of percolating electron transport pathways within these mixed regions and create morphological electron traps that enhance charge-carrier recombination and limit device quantum efficiency. These findings suggest that (i) the concentration of PCBM in the mixed regions of polymer BHJs must be above the PCBM percolation threshold in order to attain high solar cell internal quantum efficiency, and (ii) novel processing techniques, which improve polymer hole mobility while maintaining PCBM percolation within the mixed regions, should be developed in order to limit bimolecular recombination losses in optically thick devices and maximize the PCE of polymer BHJ solar cells.
TL;DR: An overview of recent developments in WSCPs and WSCSs, including their molecular design, material synthesis, functional principles and application as interface modification layers and photoactive components in emerging photovoltaic technologies such as organic/polymer solar cells, organic-inorganic hybrid solar cells and dye-sensitised solar cells are given.
Abstract: Water/alcohol-soluble conjugated polymers (WSCPs) and small molecules (WSCSs) are materials that can be processed from water or other polar solvents. They provide good opportunities to fabricate multilayer organic optoelectronic devices without interface mixing by solution processing, and exhibit a promising interface modification ability for metal or metal oxide electrodes to greatly enhance the device performance of solar cells. Moreover, owing to their intriguing processability, WSCPs and WSCSs have great potential for applying environmentally friendly processing technologies to fabricate solar cells. In this review, the authors give an overview of recent developments in WSCPs and WSCSs, including their molecular design, material synthesis, functional principles and application as interface modification layers and photoactive components in emerging photovoltaic technologies such as organic/polymer solar cells, organic–inorganic hybrid solar cells and dye-sensitised solar cells.
TL;DR: The design and synthesis of low-bandgap (LBG) conjugated polymers for use as electron donor materials for bulk heterojuction (BHJ) polymer solar cell (PSC) applications have attracted remarkable attention during the last decade.
Abstract: IO N Organic photovoltaic (OPV) devices provide an opportunity to utilize the solar energy effi ciently while maintaining low cost. [ 1 ] To harvest a greater part of the solar spectrum, lowering the energy bandgap of the active material is a major task for materials scientists. The design and synthesis of low-bandgap (LBG) conjugated polymers for use as electron donor materials for bulk heterojuction (BHJ) polymer solar cell (PSC) applications have attracted remarkable attention during the last decade. [ 2 ] The reasons for pursuing LBG polymers include: 1) The Shockley-Quiesser equation indicates a bandgap of around 1.4 eV is ideal for a single junction solar cell device. [ 3 ]