Acceptor Domains Research Articles

Unraveling the Microstructure-Related Device Stability for Polymer Solar Cells Based on Nonfullerene Small-Molecular Acceptors.

As the power conversion efficiency (PCE) of organic solar cells (OSCs) has surpassed the 17% baseline, the long-term stability of highly efficient OSCs is essential for the practical application of this photovoltaic technology. Here, the photostability and possible degradation mechanisms of three state-of-the-art polymer donors with a commonly used nonfullerene acceptor (NFA), IT-4F, are investigated. The active-layer materials show excellent intrinsic photostability. The initial morphology, in particular the mixed region, causes degradation predominantly in the fill factor (FF) under illumination. Electron traps are formed due to the reorganization of polymers and diffusion-limited aggregation of NFAs to assemble small isolated acceptor domains under illumination. These electron traps lead to losses mainly in FF, which is in contradistinction to the degradation mechanisms observed for fullerene-based OSCs. Control of the composition of NFAs close to the thermodynamic equilibrium limit while keeping adequate electron percolation and improving the initial polymer and NFA ordering are of the essence to stabilize the FF in NFA-based solar cells, which may be the key tactics to develop next-generation OSCs with high efficiency as well as excellent stability.

Critical Role of Polymer Aggregation and Miscibility in Nonfullerene‐Based Organic Photovoltaics

AbstractUnderstanding the correlation between polymer aggregation, miscibility, and device performance is important to establish a set of chemistry design rules for donor polymers with nonfullerene acceptors (NFAs). Employing a donor polymer with strong temperature‐dependent aggregation, namely PffBT4T‐2OD [poly[(5,6‐difluoro‐2,1,3‐benzothiadiazol‐4,7‐diyl)‐alt‐(3,3″′‐di(2‐octyldodecyl)‐2,2′;5′,2″;5″,2″′‐quaterthiophen‐5,5‐diyl)], also known as PCE‐11 as a base polymer, five copolymer derivatives having a different thiophene linker composition are blended with the common NFA O‐IDTBR to investigate their photovoltaic performance. While the donor polymers have similar optoelectronic properties, it is found that the device power conversion efficiency changes drastically from 1.8% to 8.7% as a function of thiophene content in the donor polymer. Results of structural characterization show that polymer aggregation and miscibility with O‐IDTBR are a strong function of the chemical composition, leading to different donor–acceptor blend morphology. Polymers having a strong tendency to aggregate are found to undergo fast aggregation prior to liquid–liquid phase separation and have a higher miscibility with NFA. These properties result in smaller mixed donor–acceptor domains, stronger PL quenching, and more efficient exciton dissociation in the resulting cells. This work indicates the importance of both polymer aggregation and donor–acceptor interaction on the formation of bulk heterojunctions in polymer:NFA blends.

Afterglow Effects as a Tool to Screen Emissive Nongeminate Charge Recombination Processes in Organic Photovoltaic Composites.

Disentangling temporally overlapping charge carrier recombination events in organic bulk heterojunctions by optical spectroscopy is challenging. Here, a new methodology for employing delayed luminescence spectroscopy is presented. The proposed method is capable of distinguishing between recombination of spatially separated charge carriers and trap-assisted charge recombination simply by monitoring the delayed luminescence (afterglow) of bulk heterojunctions with a quasi time-integrated detection scheme. Applied on the model composite of the donor poly(6,12-dihydro-6,6,12,12-tetraoctyl-indeno[1,2-b]fluorene-alt-benzothiadiazole) (PIF8BT) polymer and the acceptor ethyl-propyl perylene diimide (PDI) derivative, that is, PIF8BT:PDI, the luminescence of charge-transfer (CT) states created by nongeminate charge recombination on the ns to μs timescale is observed. Fluence-dependent, quasi time-integrated detection of the CT luminescence monitors exclusively emissive charge recombination events, while rejecting the contribution of other early-time emissive processes. Trap-assisted and bimolecular charge recombination channels are identified based on their distinct dependence on fluence. The importance of the two recombination channels is correlated with the layer's order and electrical properties of the corresponding devices. Four different microstructures of the PIF8BT:PDI composite obtained by thermal annealing are investigated. Thermal annealing of PIF8BT:PDI shrinks the PDI domains in parallel with the growth of the PIF8BT domains in the blend. Common to all states studied, the delayed CT luminescence signal is dominated by trap-assisted recombination. Yet, the minor fraction of fully separated charge recombination in the overall CT emission increases as the difference in the size of the donor and acceptor domains in the PIF8BT:PDI blend becomes larger. Electric field-induced quenching measurements on complete PIF8BT:PDI devices confirm quantitatively the dominance of emissive trap-limited charge recombination and demonstrates that only 40% of the PIF8BT/PDI CT luminescence comes from the recombination of fully-separated charges, taking place within 200 ns after photoexcitation. The method is applicable to other nonfullerene acceptor blends beyond the system discussed here, if their CT state luminescence can be monitored.

NURBS-based microstructure design for organic photovoltaics

The microstructure – spatial distribution of electron donor and acceptor domains – plays an important role in determining the photo current in thin film organic solar cells (OSCs). Optimizing the microstructure can lead to higher photo current generation, and is an active area of experimental research. There has been recent progress in framing OSC microstructure design as a computational design problem. However, most current approaches to microstructure optimization are based on volumetric distribution of material, which makes the design space very large. In contrast, we frame the microstructure design optimization problem in terms of designing the interface between the donor and acceptor regions, and thus pose it as a surface representation and optimization problem. This results in substantially reduced number of design variables, thus enabling use of standard optimization tools. In this work, we address the efficient design of OSC microstructure by using surface and curve modeling techniques to model the donor–acceptor interface, and use meta-heuristic, gradient-free optimization techniques to optimize the microstructure for maximum short circuit current generation. Our modeling framework consists of three major components: (1) geometric modeling of OSC microstructure that uses Non-Uniform Rational B-spline (NURBS) curves and surfaces to construct the free-form donor–acceptor interface, (2) photo-current generation modeling that uses a parallel, finite-element based exciton–drift–diffusion (XDD) model, and (3) optimization that utilizes genetic algorithms (GA) to optimize the OSCs microstructure via exploration of the NURBS representation. We apply these methods for the optimization of both 2D and 3D microstructures. Results show substantial improvement in current density compared to the bulk-heterojunction microstructures. These results provide promising microstructures for experimental groups to fabricate. The proposed surface representation approach seems to be a promising approach for interface design in engineered systems.

Interface-Dependent Aggregation-Induced Delayed Fluorescence in Bottlebrush Polymer Nanofibers.

Bottlebrush copolymers provide a covalent route to multicompartment nanomaterials that remain nanosegregated regardless of environmental conditions. This is particularly advantageous when combining polymers for optoelectronics, where the ability to control the interface between multiple chemically distinct polymers can be key to a device's function. Here we prepare bottlebrush nanofibers from an acridine- and triazine-based donor/acceptor pair, which have been shown to exhibit thermally activated delayed fluorescence (TADF) via through-space charge transfer (TSCT). By controlling the morphology of the donor and acceptor domains within the bottlebrush, random, miktoarm, and block bottlebrush morphologies are obtained. Using these materials, nanofibers may be prepared which (i) strongly exhibit TSCT TADF; (ii) exhibit switchable TSCT TADF based on aggregation of the fibers; or (iii) preserve the properties of the original donor and acceptor components. This work demonstrates that a bottlebrush strategy may be used to either force or prevent interactions between chemically dissimilar optoelectronic polymers in blended thin films. In this way, we establish a convenient method for either maximizing or minimizing donor-acceptor interactions in semiconductor polymer blends, using different arrangements of the same building blocks within a bottlebrush nanofiber.

Entropy promotes charge separation in bulk heterojunction organic photovoltaics

Charge separation is one of the crucial processes in the photoelectric conversion of organic photovoltaics. It is considered that organic photovoltaics have low performances because of strong Coulomb attraction. In this work, an entropy-driven charge-separation mechanism was elucidated using a graph algorithm and dynamic Monte Carlo simulations. Helmholtz energies were decreased by entropies, and had a barrier (240–270 meV) at an electron-hole distance of 6 nm; separation efficiencies at interfaces of large donor: small acceptor domains were lower than those at large donor: large acceptor domains, which can be attributed to their higher barrier-separation was promoted by a decreased barrier.

(Invited) Role of Domain Purity in Non-Fullerene Acceptor Based Organic Solar Cells

The field of non-fullerene organic solar cells (OSC) has experienced rapid development during the past few years, mainly driven by the development of novel non-fullerene acceptors and matching donor semiconductors with device efficiencies approaching 15%. However, organic solar cell material development has progressed via a trial-and-error approach with limited understanding of the materials’ structure–property relationships and the underlying device physics of non-fullerene devices. In addition, the availability of hundreds of donor and acceptor semiconductors creates a large pool of possible donor–acceptor combinations, which poses a daunting challenge for rationally screening material combinations. Resonant soft X-ray scattering (RSoXS) has proven to be a powerful technique to measure domain purity in OSC active layer blends. In polymer-fullerene systems, RSoXS has shown that higher average domain purity is generally correlated to device performance. A simple interpretation of RSoXS purity measurements is complicated by the consideration that real morphologies may be composed of three or more phases, with mixed amorphous regions in addition to relatively pure, aggregated donor and acceptor domains. Whilst charges are understood to migrate to the aggregated domains due to a favorable electronic landscape, these charges might be effectively trapped in aggregates if there is insufficient number of percolating pathways in the amorphous mixed regions. Conversely, if the mixed regions have a composition much beyond the percolation threshold or if the volume faction of the mixed regions is large, then recombination is enhanced. Therefore, understanding the role of domain purity over different length scales and controlling the mixed amorphous phase for maximum charge creation and minimum recombination remains a principal challenge for non-fullerene OSCs. We will summarize several of our RSoXS studies that compare non-fullerene acceptor based organic solar cells having different primary chemical structures of the constituents and with significant processing variations. Our analysis suggests that mixed regions are often detrimental to good performance in these systems, typically having a pronounced negative impact on FF. Optimizing performance continues to be a delicate balance of possibly competing factors and the volume fraction of the ideal morphology remains to be determined. However, the miscibility of blend components, which might be probed using near-edge X-ray absorption spectroscopy as a screening tool, can guide expectations of achievable phase purity and ultimately the achievable performance of the active layer.

Charge Transfer and Interface Effects in Co‐Assembled Circular Donor/Acceptor Complexes for Organic Photovoltaics

AbstractAn in‐depth theoretical characterization of alternative structural architectures is reported for use in organic photovoltaic devices (OPV): a host–guest structure where a circular π‐conjugated nanohoop electron donor encapsulates an electron acceptor fullerene, forming a circular donor/acceptor complex. The mesoscale morphology, pairwise charge transport at the donor or acceptor domains, and charge transfer reactions at the donor/acceptor interfaces are calculated. For a fundamental understanding, three prototype complexes are considered: C60@10‐cycloparaphenylene (C60@[10]CPP), C70@11‐cycloparaphenylene (C70@[11]CPP), C70@3‐cycloparaphenyleneacetylene (C70@[3]CPPA). It is found that solid state packing is crucial for the interface morphology, charge transport, and the electronic performance of the materials. While contorted and stiff packing result in small structural disorder, electron–phonon coupling is reduced, charge mobility and charge transfer is limited by the complex transport network. In contrast, a regular packing arrangement suggests an efficient charge transport; however, it is limited by the large amount of disorder and relatively large electron–phonon coupling. Hole and electron mobilities in the order of 10−3 to 0.1 cm2 Vs−1 and 10−5 to 10−2 cm2 Vs−1 have been extracted, respectively, and electron mobilities are found to be very susceptible to intermolecular arrangements. Power conversion efficiency of ≈10% under 1 sun illumination has been offered from time‐domain drift diffusion model.

Increased charge transfer state separationviareduced mixed phase interface in polymer solar cells

For the first time, the mixed phase is quantified within a polymer solar cell and correlated to CT state separation and charge extraction efficiency. A causal relationship is revealed that a narrow mixed interphase between pure donor and pure acceptor domains is a key driver in device efficiency.

Fluorescent Sulphur- and Nitrogen-Containing Porous Polymers with Tuneable Donor-Acceptor Domains for Light-Driven Hydrogen Evolution.

Light-driven water splitting is a potential source of abundant, clean energy, yet efficient charge-separation and size and position of the bandgap in heterogeneous photocatalysts are challenging to predict and design. Synthetic attempts to tune the bandgap of polymer photocatalysts classically rely on variations of the sizes of their π-conjugated domains. However, only donor-acceptor dyads hold the key to prevent undesired electron-hole recombination within the catalyst via efficient charge separation. Building on our previous success in incorporating electron-donating, sulphur-containing linkers and electron-withdrawing, triazine (C3 N3 ) units into porous polymers, we report the synthesis of six visible-light-active, triazine-based polymers with a high heteroatom-content of S and N that photocatalytically generate H2 from water: up to 915 μmol h-1 g-1 with Pt co-catalyst, and-as one of the highest to-date reported values -200 μmol h-1 g-1 without. The highly modular Sonogashira-Hagihara cross-coupling reaction we employ, enables a systematic study of mixed (S, N, C) and (N, C)-only polymer systems. Our results highlight that photocatalytic water-splitting does not only require an ideal optical bandgap of ≈2.2 eV, but that the choice of donor-acceptor motifs profoundly impacts charge-transfer and catalytic activity.

Designing Efficient Energy Funneling Kinetics in Ruddlesden-Popper Perovskites for High-Performance Light-Emitting Diodes.

Mixed Ruddlesden-Popper (RP) perovskites are of great interest in light-emitting diodes (LEDs), due to the efficient energy transfer (funneling) from high-bandgap (donor) domains to low-bandgap (acceptor) domains, which leads to enhanced photoluminescence (PL) intensity, long PL lifetime, and high-efficiency LEDs. However, the influence of reduced effective emitter centers in the active emissive film, as well as the implications of electrical injection into the larger bandgap donor material, have not been addressed in the context of an active device. The electrical and optical signatures of the energy cascading mechanisms are critically assessed and modulated in a model RP perovskite series ((C8 H17 NH3 )2 (CH(NH2 )2 )m-1 Pbm Br3m+1 ). Optimized devices demonstrate a current efficiency of 22.9 cd A-1 and 5% external quantum efficiency, more than five times higher than systems where funneling is absent. The signature of nonideal funneling in RP perovskites is revealed by the appearance of donor electroluminescence from the device, followed by a reduction in the LED performance.

Enhance the performance of polymer solar cells via extension of the flanking end groups of fused ring acceptors

Two new fused ring electron acceptors (FREAs) IDT-IC-T and IDT-IC-B with thienyl or phenyl substituents at the terminal INCN unit are synthesized. Theoretical calculations indicate that the two acceptors dominantly favor an intermolecular π-π stacking between the flanking terminal groups. The twist angle between the aryl substituent and INCN unit has a significant influence on the π-π stacking distance of terminal unit. IDT-IC-T with a smaller twist angle has a shorter π-π stacking distance than that of IDT-IC-B with a larger twist angle. In addition, extending the conjugation also affects the blend film morphology. IDT-IC-T and IDT-IC-B based photoactive films show appropriate nanoscale phase separations; whereas, blend films based on the parent compound IDT-IC show large-size acceptor domains. As expected, PBDB-T : IDT-IC-T blend films show higher and more balanced electron and hole mobilities. Moreover, these two acceptors present a good charge-transport connectivity arising from the extended conjugation and the increased intermolecular overlapping. Ultimately, IDT-IC-T demonstrates the highest electron mobility (1.47×10−4 cm2 V−1 s−1) and the best power conversion efficiency (PCE) of 9.43%. As for IDT-IC, which only shows an electron mobility of 7.33×10−5 cm2 V−1 s−1 and a PCE of 5.82%. These findings provide a facile and effective way to improve the photovoltaic performance.

Progress in Poly (3‐Hexylthiophene) Organic Solar Cells and the Influence of Its Molecular Weight on Device Performance

AbstractPoly (3‐hexylthiophene) (P3HT) was an early frontrunner in the development of donor polymers to be used in organic photovoltaics. A relatively straightforward and inexpensive synthesis suggests that it may be the most viable donor polymer to use in large‐scale commercial organic solar cells. Replacing fullerenes with new electron acceptors has led to significant improvements in device performance and stability, with devices now able to exceed an efficiency of 7%. Past studies have reported a dependence of device performance on the molecular weight of the polymer in fullerene‐containing blends, however, with nonfullerene acceptors now showing promise a similar study was needed. P3HT blends, with two nonfullerene acceptors (O‐IDTBR and EH‐IDTBR), were probed using a number of polymer batches with varying molecular weights. O‐IDTBR was shown to exhibit a dependence on the polymer molecular weight, with optimal performance achieved with a 34 kDa polymer, while EH‐IDTBR displayed an independence in performance with varying polymer molecular weight. Probing the thermal and morphological behavior of the P3HT:O‐IDTBR blends suggests that an optimal morphology with pronounced donor and acceptor domains was only achieved with the 34 kDa polymer, and a greater degree of mixing was exhibited in the other blends, likely leading to poorer device performance.

The Role of FRET in Non-Fullerene Organic Solar Cells: Implications for Molecular Design

Non-fullerene acceptors (NFAs) have been demonstrated to be promising candidates for highly efficient organic photovoltaic (OPV) devices. The tunability of absorption characteristics of NFAs can be used to make OPVs with complementary donor-acceptor absorption to cover a broad range of the solar spectrum. However, both charge transfer from donor to acceptor moieties and energy (energy) transfer from high-bandgap to low-bandgap materials are possible in such structures. Here, we show that when charge transfer and exciton transfer processes are both present, the coexistence of excitons in both domains can cause a loss mechanism. Charge separation of excitons in a low-bandgap material is hindered due to exciton population in the larger bandgap acceptor domains. Our results further show that excitons in low-bandgap material should have a relatively long lifetime compared to the transfer time of excitons from higher bandgap material in order to contribute to the charge separation. These observations provide significant guidance for design and development of new materials in OPV applications.

Control of Geminate Recombination by the Material Composition and Processing Conditions in Novel Polymer: Nonfullerene Acceptor Photovoltaic Devices.

Herein, we report on the charge dynamics of photovoltaic devices based on two novel small-molecule nonfullerene acceptors featuring a central ketone unit. Using ultrafast near-infrared spectroscopy with optical and photocurrent detection methods, we identify one of the key loss channels in the devices as geminate recombination (GR) of interfacial charge transfer states (CTSs). We find that the magnitude of GR is highly sensitive to the choice of solvent and annealing conditions. Interestingly, regardless of these processing conditions, the same lifetime for GR (∼130 ps) is obtained by both detection methods upon decomposing the complex broadband transient optical spectra, suggesting this time scale is inherent and independent of morphology. These observations suggest that the CTSs in the studied material blends are mostly strongly bound, and that charge generation from these states is highly inefficient. We further rationalize our results by considering the impact of the processing on the morphology of the mixed donor and acceptor domains and discuss the potential consequences of the early charge dynamics on the performance of emerging nonfullerene photovoltaic devices. Our results demonstrate that careful choice of processing conditions enables enhanced exciton harvesting and suppression of GR by more than 3 orders of magnitude.

Nanoscale Domain Imaging of All-Polymer Organic Solar Cells by Photo-Induced Force Microscopy.

Rapid nanoscale imaging of the bulk heterojunction layer in organic solar cells is essential to the continued development of high-performance devices. Unfortunately, commonly used imaging techniques such as tunneling electron microscopy (TEM) and atomic force microscopy (AFM) suffer from significant drawbacks. For instance, assuming domain identity from phase contrast or topographical features can lead to inaccurate morphological conclusions. Here we demonstrate a technique known as photo-induced force microscopy (PiFM) for imaging organic solar cell bulk heterojunctions with nanoscale chemical specificity. PiFM is a relatively recent scanning probe microscopy technique that combines an AFM tip with a tunable infrared laser to induce a dipole for chemical imaging. Coupling the nanometer resolution of AFM with the chemical specificity of a tuned IR laser, we are able to spatially map the donor and acceptor domains in a model all-polymer bulk heterojunction with resolution approaching 10 nm. Domain size from PiFM images is compared to bulk-averaged results from resonant soft X-ray scattering, indicating excellent quantitative agreement. Further, we demonstrate that in our all-polymer system, the AFM topography, AFM phase, and PiFM show poor correlation, highlighting the need to move beyond standard AFM for morphology characterization of bulk heterojunctions.

Interplay of Interfacial Layers and Blend Composition To Reduce Thermal Degradation of Polymer Solar Cells at High Temperature.

The thermal stability of printed polymer solar cells at elevated temperatures needs to be improved to achieve high-throughput fabrication including annealing steps as well as long-term stability. During device processing, thermal annealing impacts both the organic photoactive layer, and the two interfacial layers make detailed studies of degradation mechanism delicate. A recently identified thermally stable poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]]:[6,6]-phenyl-C71-butyric acid methyl ester (PTB7:PC70BM) blend as photoactive layer in combination with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate as hole extraction layer is used here to focus on the impact of electron extraction layer (EEL) on the thermal stability of solar cells. Solar cells processed with densely packed ZnO nanoparticle layers still show 92% of the initial efficiency after constant annealing during 1 day at 140 °C, whereas partially covering ZnO layers as well as an evaporated calcium layer leads to performance losses of up to 30%. This demonstrates that the nature and morphology of EELs highly influence the thermal stability of the device. We extend our study to thermally unstable PTB7:[6,6]-phenyl-C61-butyric acid methyl ester (PC60BM) blends to highlight the impact of ZnO on the device degradation during annealing. Importantly, only 12% loss in photocurrent density is observed after annealing at 140 °C during 1 day when using closely packed ZnO. This is in stark contrast to literature and addressed here to the use of a stable double-sided confinement during thermal annealing. The underlying mechanism of the inhibition of photocurrent losses is revealed by electron microscopy imaging and spatially resolved spectroscopy. We found that the double-sided confinement suppresses extensive fullerene diffusion during the annealing step, but with still an increase in size and distance of the enriched donor and acceptor domains inside the photoactive layer by an average factor of 5. The later result in combination with comparably small photocurrent density losses indicates the existence of an efficient transport of minority charge carriers inside the donor and acceptor enriched phases in PTB7:PC60BM blends.

Ternary System with Controlled Structure: A New Strategy toward Efficient Organic Photovoltaics.

Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin-coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal-semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C-ternary) is reported. The C-ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin-coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C-ternary are enhanced by 14-21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene-based and fullerene-free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene-free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation.

Exploring the conformations of nitric oxide synthase with fluorescence.

Multi-domain oxidoreductases are a family of enzymes that catalyze oxidation-reduction reactions through a series of electron transfers. Efficient electron transfer requires a sequence of protein conformations that position electron donor and acceptor domains in close proximity to each other so that electron transfer can occur efficiently. An example is mammalian nitric oxide synthase (NOS), which consists of an N-terminal oxygenase domain containing heme and a C-terminal reductase domain containing NADPH/FAD and FMN subdomains. We describe the use of time-resolved and single-molecule fluorescence to detect and characterize the conformations and conformational dynamics of the neuronal and endothelial isoforms of NOS. Fluorescence signals are provided by a fluorescent dye attached to the Ca2+-signaling protein calmodulin (CaM), which regulates NOS activity. Time-resolved fluorescence decays reveal the presence of at least four underlying conformational states that are differentiated by the extent of fluorescence quenching. Single-molecule fluorescence displays transitions between conformational states on the time scales of milliseconds to seconds. This review describes the type of information available by analysis of time-resolved and single-molecule fluorescence experiments.

Colloidal distribution of the PCPDTBT and VOPcPhO in the organic amalgam thin films and their optical properties

In this article, we investigated the optical properties and colloidal distribution of the PCPDTBT and VOPcPhO in the organic amalgam thin films prepared by spin-coating technique. A very even dispersion of donor and acceptor domains in the binary blend has been obtained. The thin films were characterized using atomic force microscopy, UV–Vis optical absorption spectra, photo luminescence, and Raman spectral measurements. The combination of these two materials stretched the absorption spectra over the whole visible region (400–800 nm). Optical and structural properties of the proposed combination argue its potential in organic optoelectronics applications.