Bulk Heterojunction Blend Research Articles

Direct Correlation of Nanoscale Morphology and Device Performance to Study Photocurrent Generation in Donor-Enriched Phases of Polymer Solar Cells.

The nanoscale morphology of polymer blends is a key parameter to reach high efficiency in bulk heterojunction solar cells. Thereby, research typically focusing on optimal blend morphologies while studying nonoptimized blends may give insight into blend designs that can prove more robust against morphology defects. Here, we focus on the direct correlation of morphology and device performance of thieno[3,4-b]-thiophene-alt-benzodithiophene (PTB7):[6,6]phenyl C71 butyric acid methyl ester (PC71BM) bulk heterojunction (BHJ) blends processed without additives in different donor/acceptor weight ratios. We show that while blends of a 1:1.5 ratio are composed of large donor-enriched and fullerene domains beyond the exciton diffusion length, reducing the ratio below 1:0.5 leads to blends composed purely of polymer-enriched domains. Importantly, the photocurrent density in such blends can reach values between 45 and 60% of those reached for fully optimized blends using additives. We provide here direct visual evidence that fullerenes in the donor-enriched domains are not distributed homogeneously but fluctuate locally. To this end, we performed compositional nanoscale morphology analysis of the blend using spectroscopic imaging of low-energy-loss electrons using a transmission electron microscope. Charge transport measurement in combination with molecular dynamics simulations shows that the fullerene substructures inside the polymer phase generate efficient electron transport in the polymer-enriched phase. Furthermore, we show that the formation of densely packed regions of fullerene inside the polymer phase is driven by the PTB7:PC71BM enthalpy of mixing. The occurrence of such a nanoscale network of fullerene clusters leads to a reduction of electron trap states and thus efficient extraction of photocurrent inside the polymer domain. Suitable tuning of the polymer-acceptor interaction can thus introduce acceptor subnetworks in polymer-enriched phases, improving the tolerance for high-efficiency BHJ toward morphological defects such as donor-enriched domains exceeding the exciton diffusion length.

Appropriate Molecular Interaction Enabling Perfect Balance Between Induced Crystallinity and Phase Separation for Efficient Photovoltaic Blends

Fluorination is a promising modification method to adjust the photophysical profiles of organic semiconductors. Notably, the fluorine modification on donor or acceptor materials could impact the molecular interaction, which is strongly related to the morphology of bulk heterojunction (BHJ) blends and the resultant device performance. Therefore, it's essential to investigate how the molecular interaction affect the morphology of BHJ films. In this study, a new fluorinated polymer PBDB-PSF is synthesized to investigate the molecular interaction in both nonfluorinated (ITIC) and fluorinated (IT-4F) systems. The results reveal that the F-F interaction in PBDB-PSF:IT-4F system could effectively induce the crystallization of IT-4F while retaining ideal phase separation scale, resulting in outstanding charge transport. On the contrary, poor morphology can be observed in PBDB-PSF:ITIC system due to the unbalanced molecular interaction. As a consequence, the PBDB-PSF:IT-4F device delivers an excellent PCE of 13.63%, which greatly exceeds PBDB-PSF:ITIC device (9.84%). These results highlight manipulating the micromorphology in regard of molecular interaction.

Tackling Performance Challenges in Organic Photovoltaics: An Overview about Compatibilizers.

Organic Photovoltaics (OPVs) based on Bulk Heterojunction (BHJ) blends are a mature technology. Having started their intensive development two decades ago, their low cost, processability and flexibility rapidly funneled the interest of the scientific community, searching for new solutions to expand solar photovoltaics market and promote sustainable development. However, their robust implementation is hampered by some issues, concerning the choice of the donor/acceptor materials, the device thermal/photo-stability, and, last but not least, their morphology. Indeed, the morphological profile of BHJs has a strong impact over charge generation, collection, and recombination processes; control over nano/microstructural morphology would be desirable, aiming at finely tuning the device performance and overcoming those previously mentioned critical issues. The employ of compatibilizers has emerged as a promising, economically sustainable, and widely applicable approach for the donor/acceptor interface (D/A-I) optimization. Thus, improvements in the global performance of the devices can be achieved without making use of more complex architectures. Even though several materials have been deeply documented and reported as effective compatibilizing agents, scientific reports are quite fragmentary. Here we would like to offer a panoramic overview of the literature on compatibilizers, focusing on the progression documented in the last decade.

Towards Efficient Integrated Perovskite/Organic Bulk Heterojunction Solar Cells: Interfacial Energetic Requirement to Reduce Charge Carrier Recombination Losses

AbstractIntegrated perovskite/organic bulk heterojunction (BHJ) solar cells have the potential to enhance the efficiency of perovskite solar cells by a simple one‐step deposition of an organic BHJ blend photoactive layer on top of the perovskite absorber. It is found that inverted structure integrated solar cells show significantly increased short‐circuit current (Jsc) gained from the complementary absorption of the organic BHJ layer compared to the reference perovskite‐only devices. However, this increase in Jsc is not directly reflected as an increase in power conversion efficiency of the devices due to a loss of fill factor. Herein, the origin of this efficiency loss is investigated. It is found that a significant energetic barrier (≈250 meV) exists at the perovskite/organic BHJ interface. This interfacial barrier prevents efficient transport of photogenerated charge carriers (holes) from the BHJ layer to the perovskite layer, leading to charge accumulation at the perovskite/BHJ interface. Such accumulation is found to cause undesirable recombination of charge carriers, lowering surface photovoltage of the photoactive layers and device efficiency via fill factor loss. The results highlight a critical role of the interfacial energetics in such integrated cells and provide useful guidelines for photoactive materials (both perovskite and organic semiconductors) required for high‐performance devices.

Over 15% Efficiency in Ternary Organic Solar Cells by Enhanced Charge Transport and Reduced Energy Loss

In this study, an efficient ternary bulk-heterojunction (BHJ) organic solar cell (OSC) is demonstrated by incorporating two acceptors, PC61BM and ITC6-4F with a polymer donor (PM6). It reveals that the addition of PC61BM not only enhances the electron mobility of the derived BHJ blend but also facilitates the exciton dissociation, resulting in a more balanced charge transport alongside with reduced trap-assisted charge recombination. Consequently, as compared to the pristine PM6:ITC6-4F device, the optimal ternary OSC is revealed to deliver an improved power conversion efficiency (PCE) of 15.11% with boosted JSC, VOC and FF simultaneously. The resultant VOC and FF are among the highest values recorded in the literature for the ternary OSCs with PCE exceeding 15%. This result thus suggests that besides improving the charge transport characteristics in devices, incorporating fullerene derivative as part of the acceptor can also improve the resultant VOC, which can reduce the energy loss to realize efficient organic photovoltaic.

Efficient Organic Solar Cell with 16.88% Efficiency Enabled by Refined Acceptor Crystallization and Morphology with Improved Charge Transfer and Transport Properties

AbstractSingle‐layered organic solar cells (OSCs) using nonfullerene acceptors have reached 16% efficiency. Such a breakthrough has inspired new sparks for the development of the next generation of OSC materials. In addition to the optimization of electronic structure, it is important to investigate the essential solid‐state structure that guides the high efficiency of bulk heterojunction blends, which provides insight in understanding how to pair an efficient donor–acceptor mixture and refine film morphology. In this study, a thorough analysis is executed to reveal morphology details, and the results demonstrate that Y6 can form a unique 2D packing with a polymer‐like conjugated backbone oriented normal to the substrate, controlled by the processing solvent and thermal annealing conditions. Such morphology provides improved carrier transport and ultrafast hole and electron transfer, leading to improved device performance, and the best optimized device shows a power conversion efficiency of 16.88% (16.4% certified). This work reveals the importance of film morphology and the mechanism by which it affects device performance. A full set of analytical methods and processing conditions are executed to achieve high efficiency solar cells from materials design to device optimization, which will be useful in future OSC technology development.

Direct characterization of vertical molecular distributions of organic bulk heterojunction structure by photoemission spectroscopy combined with argon gas cluster ion beam sputtering

The characterization of the vertical molecular distribution of organic bulk heterojunction (BHJ) structures is crucial to the development of high-performance organic photovoltaic (OPV) devices. Herein, we report a novel and direct method for the characterization of the vertical composition gradient of a BHJ structure. Ar gas cluster ion beam (GCIB) sputtering provided a uniform sputtering yield that preserved the chemical structure of the organic semiconducting materials. The combination of X-ray photoelectron spectroscopy (XPS) and Ar GCIB sputtering facilitated the accurate analysis of the vertical molecular distribution of a regioregular poly(3-​hexylthiophene) (P3HT) and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) BHJ structure. The J-V characteristics and depth profiles of the as-deposited, ethanol-annealed, and chloroform-annealed devices were examined to demonstrate the usefulness of Ar GCIB sputtering in optimizing the BHJ morphology. Chloroform-annealed device exhibited both the best performance and the most homogeneous morphology among the three prepared samples, and the thickness of the P3HT-rich region was substantially reduced from 20 to 10 nm. Consequently, these results provide important information about the correlation between the vertical molecular distribution of a BHJ blend structure and power conversion efficiency of an OPV device.

Impact of Polymer Backbone Fluorination on the Charge Generation/Recombination Patterns and Vertical Phase Segregation in Bulk Heterojunction Organic Solar Cells.

Incorporating fluorine (–F) substituents along the main-chains of polymer donors and acceptors is an effective strategy toward efficient bulk-heterojunction (BHJ) solar cells. Specifically, F-substituted polymers often exhibit planar conformations, leading to favorable packing, and electronic coupling. However, the effects of fluorine substituents on the charge generation and recombination characteristics that determine the overall efficiency of BHJ active layers remain critically important issues to examine. In this report, two PBDT[2X]T polymer analogs –poly[4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4, 5-b′]dithiophene-thiophene] [PBDT[2H]T] and its F-substituted counterpart poly[4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b′]dithiophene-3,4-difluoro-thiophene] [PBDT[2F]T]—are studied to systematically examine how –F substituents impact the blend morphology, charge generation, carrier recombination and extraction in BHJ solar cells. Considering the large efficiency differences between PBDT[2H]T- and PBDT[2F]T-based BHJ devices, significant emphasis is given to characterizing the out-of-plane morphology of the blend films as vertical phase-separation characteristics are known to have dramatic effects on charge transport and carrier extraction in polymer-fullerene BHJ solar cells. Herein, we use electron energy loss spectroscopy (EELS) in tandem with charge transport characterization to examine PBDT[2X]T-fullerene blend films. Our analyses show that PBDT[2H]T and PBDT[2F]T possess very different charge generation, recombination and extraction characteristics, resulting from distinct aggregation, and phase-distribution within the BHJ blend films.

Real‐Time Study on Structure Formation and the Intercalation Process of Polymer: Fullerene Bulk Heterojunction Thin Films

Fullerene intercalation between the side chains of conjugated polymers has a detrimental impact on both charge separation and charge transport processes in bulk heterojunction (BHJ) organic photovoltaic cells (OPVs). In situ grazing incidence X‐ray scattering experiments allow to characterize the structure formation, drying kinetics, and intercalation in blends of phenyl‐c61‐butyric acid methyl ester (PC60BM) and poly(2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene) named (pBTTT‐C14) from their 1,2‐orthodichlorobenzene (oDCB) solutions with different volume fractions of dodecanoic acid methyl ester (Me12) as a solvent additive. The structure formation process during evaporation of the solvent:additive mixture can be described by five periods, which are correlated to a multistep contraction of the lamellar stacking of the bimolecular crystals. The onset of crystallization is delayed by increasing the additive volume fraction in the coating solution leading to a promoted crystallinity. A conclusive picture of fullerene intercalation and additive‐tuned structural evolution during the drying of thin films of the polymer:fullerene BHJ blends will be presented.

Tuning fullerene miscibility with porphyrin-terminated P3HTs in bulk heterojunction blends.

Understanding and manipulating the miscibility of donor and acceptor components in the active layer morphology is important to optimize the longevity of organic photovoltaic devices and control power conversion efficiency. In pursuit of this goal, a "porphyrin-capped" poly(3-hexylthiophene) was synthesized to take advantage of strong porphyrin:fullerene intermolecular interactions that modify fullerene miscibility in the active layer. End-functionalized poly(3-hexylthiophene) was synthesized via catalyst transfer polymerization and subsequently functionalized with a porphyrin moiety via post-polymerization modification. UV-vis spectroscopy and X-ray diffraction measurements show that the porphyrin-functionalized poly(3-hexylthiophene) exhibits increased intermolecular interactions with phenyl-C61-butyric acid methyl ester (PCBM) in the solid state compared to unfunctionalized poly(3-hexylthiophene) without sacrificing microstructure ordering that facilitates optimal charge transport properties. Additionally, differential scanning calorimetry revealed porphyrin-functionalized poly(3-hexylthiophene) crystallization decreased only slightly (1-6%) compared to unfunctionalized poly(3-hexylthiophenes) while increasing fullerene miscibility by 55%. Preliminary organic photovoltaic device results indicate device power conversion efficiency is sensitive to additive loading levels, as evident by a slight increase in power conversion efficiency at low additive loading levels but a continuous decrease with increased loading levels. While the increased fullerene miscibility is not balanced with significant increases in power conversion efficiency, this approach suggests that integrating non-bonded interaction potentials is a useful pathway for manipulating the morphology of the bulk heterojunction thin film, and porphyrin-functionalized poly(3-hexylthiophenes) may be useful additives in that regard.

Bulk-Heterojunction with Long-Range Ordering: C60 Single-Crystal with Incorporated Conjugated Polymer Networks.

Bulk-heterojunction (BHJ) blends are commonly used as active materials for optoelectronics. Ordering of molecular packing in blends is critical to their electronic properties, spurring investigation on how to obtain BHJ with long-range ordering. However, the difficulty in controlling crystallization during blending limits the crystallinity. Developing a new strategy instead of conventional blending is, thus, needed. Inspired by biomineralization, here, C60 single-crystals are prepared in organogel matrix of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenvinylene] (MEH-PPV) to form MEH-PPV:C60 composites. Essentially, networks of MEH-PPV are incorporated into growing C60 crystals and penetrate throughout the crystals, resulting in crystal/gel-network interpenetrating composites. Despite the coexistence of MEH-PPV, the C60 crystalline component maintains single-crystallinity and the composite exhibits as BHJ with long-range ordering. Furthermore, compared with blends, the long-range ordered BHJ shows a higher efficiency of charge dissociation and better performance in photodetection, exemplifying the advantage of ordering on organic electronics. Hence, this work provides a new platform to study BHJ with long-range ordering.

Bimolecular crystal instability and morphology of bulk heterojunction blends in organic and perovskite solar cells

The in situ crystallization study reveals that size compatibility plays a key role in governing the formation of bimolecular crystals.

Subtle Molecular Tailoring Induces Significant Morphology Optimization Enabling over 16% Efficiency Organic Solar Cells with Efficient Charge Generation.

Manipulating charge generation in a broad spectral region has proved to be crucial for nonfullerene-electron-acceptor-based organic solar cells (OSCs). 16.64% high efficiency binary OSCs are achieved through the use of a novel electron acceptor AQx-2 with quinoxaline-containing fused core and PBDB-TF as donor. The significant increase in photovoltaic performance of AQx-2 based devices is obtained merely by a subtle tailoring in molecular structure of its analogue AQx-1. Combining the detailed morphology and transient absorption spectroscopy analyses, a good structure-morphology-property relationship is established. The stronger π-π interaction results in efficient electron hopping and balanced electron and hole mobilities attributed to good charge transport. Moreover, the reduced phase separation morphology of AQx-2-based bulk heterojunction blend boosts hole transfer and suppresses geminate recombination. Such success in molecule design and precise morphology optimization may lead to next-generation high-performance OSCs.

Roll-to-roll micro-gravure printed P3HT:PCBM organic solar cells

Roll-to-roll (R2R) micro-gravure printing is an attractive technology for fabricating organic solar cells (OSCs) at low cost with high throughput. The nanoscale morphology and phase separation of R2R micro-gravure printed active layers have a large influence on the photovoltaic performance of OSCs. Herein, we demonstrate that the photovoltaic performance of R2R micro-gravure printed P3HT:PCBM OSCs can be enhanced by optimizing phase separation using solvent engineering. R2R micro-gravure printed P3HT:PCBM blend film with chlorobenzene solvent enabled optimized phase separation and formation of a fine-tuned interpenetrating network in a bulk heterojunction (BHJ) layer compared with a film with 1,2-dicholorobenzene solvent. This creates an optimal transport pathway and therefore effectively enhances charge transport in the BHJ blend film and boosts device performance. This research shows that high-performance OSCs could be fabricated by large-scale, R2R micro-gravure printing with solvent engineering, which would accelerate the development of fully R2R micro-gravure printed flexible OSCs.

Understanding the High Performance of over 15% Efficiency in Single-Junction Bulk Heterojunction Organic Solar Cells.

The highly efficient single-junction bulk-heterojunction (BHJ) PM6:Y6 system can achieve high open-circuit voltages (VOC ) while maintaining exceptional fill-factor (FF) and short-circuit current (JSC ) values. With a low energetic offset, the blend system is found to exhibit radiative and non-radiative recombination losses that are among the lower reported values in the literature. Recombination and extraction dynamic studies reveal that the device shows moderate non-geminate recombination coupled with exceptional extraction throughout the relevant operating conditions. Several surface and bulk characterization techniques are employed to understand the phase separation, long-range ordering, as well as donor:acceptor (D:A) inter- and intramolecular interactions at an atomic-level resolution. This is achieved using photo-conductive atomic force microscopy, grazing-incidence wide-angle X-ray scattering, and solid-state 19 F magic-angle-spinning NMR spectroscopy. The synergy of multifaceted characterization and device physics is used to uncover key insights, for the first time, on the structure-property relationships of this high-performing BHJ blend. Detailed information about atomically resolved D:A interactions and packing reveals that the high performance of over 15% efficiency in this blend can be correlated to a beneficial morphology that allows high JSC and FF to be retained despite the low energetic offset.

Bis‐Diketopyrrolopyrrole and Carbazole‐Based Terpolymer for High Performance Organic Field‐Effect Transistors and Infra‐Red Photodiodes

AbstractCarbazoles constitute one of the most widely used donor moieties for organic semiconductors due to their excellent hole transport and high environmental stability. However, they are seldomly used in recent high performance donor–acceptor (D–A) copolymers. In the present study, a planar regular terpolymer, PCbisDPP, composed of carbazole and thiophene flanked bis‐diketopyrrolopyrrole (bis‐DPP) for application as an active layer for high‐performance organic devices is reported. Organic field‐effect transistors with PCbisDPP as the active layer exhibit field‐effect mobility up to 1.48 cm2 v−1 s−1, which to the best of the current knowledge corresponds to the highest hole mobility reported to date for carbazole‐based D–A polymers. The high mobility is achieved via a tailored polymer‐design resulting in high crystallinity and a strong aggregating property without sacrificing solubility. PCbisDPP is applied as an active donor material in organic photodiode with fullerene derivative PC61BM as an acceptor in a bulk heterojunction blend. Binary additive combinations (tetralin: 1,8‐diiodooxtane (3:3) v/v%) utilization achieves an impressive performance with an external quantum efficiency of 80%, an average responsivity of 309.1 mA W−1, and specific detectivity of 4.73 × 1011 Jones in the near infra‐red light region (730 nm) utilizing a simple single layer organic photodiode structure as ITO/PEDOT:PSS/PCbisDPP:PC61BM/LiF/Al.

Observing electron transport and percolation in selected bulk heterojunctions bearing fullerene derivatives, non-fullerene small molecules, and polymeric acceptors

We systematically study how electrons achieve percolation pathways in a bulk-heterojunction (BHJ) blend as the weight fraction of the electron acceptor is altered. Three different classes of BHJs are explored: BHJs that contain (1) fullerene-based acceptors, (2) non-fullerene small molecules, and (3) polymer acceptors. The nano-topologies of acceptors in (1) to (3) can be approximately associated with spheres, oblates (plates) and prolates (long rods), respectively. We discover that the weight fraction of the acceptor for electron percolation to complete is successively reduced in the order of fullerenes (0.32), non-fullerene (NF) small molecules (0.25), and polymers (0.11). A new parameter, namely, the effective volume fraction, χ, is introduced to quantify the fraction of the acceptor moieties that can contribute to electron transport in the BHJs. The electron percolation regions can be fitted with a model that considers the shapes of the acceptors and their χ in the BHJs. An all-polymer BHJ containing PTB7-Th:N2200 exhibits the largest χ (0.6–0.8), indicating N2200 acceptors are the most effective in transportation of electrons. All-polymer BHJs can better preserve their electron transport capability arising from composition variations, and they are immuned from the introduction of inert materials or the exposure of moisture, in stark contrast to fullerene-based BHJs. Our results correlate the electron transport behaviors to the nano-topologies of acceptors for BHJ cells, and offer guidance to tune the compositions and understand the nano-morphology of BHJ cells using different classes of acceptors.

Solution-Processed Semitransparent Organic Photovoltaics: From Molecular Design to Device Performance.

Recent research efforts on solution-processed semitransparent organic solar cells (OSCs) are presented. Essential properties of organic donor:acceptor bulk heterojunction blends and electrode materials, required for the combination of simultaneous high power conversion efficiency (PCE) and average visible transmittance of photovoltaic devices, are presented from the materials science and device engineering points of view. Aspects of optical perception, charge generation-recombination, and extraction processes relevant for semitransparent OSCs are also discussed in detail. Furthermore, the theoretical limits of PCE for fully transparent OSCs, compared to the performance of the best reported semitransparent OSCs, and options for further optimization are discussed.

In Situ Structure Characterization in Slot‐Die‐Printed All‐Polymer Solar Cells with Efficiency Over 9%

Herein, high‐performance printed all‐polymer solar cells (all‐PSCs) based on a bulk‐heterojunction (BHJ) blend film are demonstrated using PTzBI as the donor and N2200 as the acceptor. A slot‐die process is used to prepare the BHJ blend, which is a cost‐effective, high‐throughput approach to achieve large‐area photovoltaic devices. The real‐time crystallization of polymers in the film drying process is investigated by in situ grazing incidence wide‐angle X‐ray scattering characterization. Printing is found to significantly improve the crystallinity of the polymer blend in comparison with spin coating. Moreover, printing with 1,8‐diiodooctane as the solvent additive enhances the polymer aggregation and crystallization during solvent evaporation, eventually leading to multi‐length‐scale phase separation, with PTzBI‐rich domains in‐between the N2200 crystalline fibers. This unique morphology achieved by printing fabrication results in an impressively high power conversion efficiency of 9.10%, which is the highest efficiency reported for printed all‐PSCs. These findings provide important guidelines for controlling film drying dynamics for processing all‐PSCs.

(Invited) Transient Electron Spin Polarization Imaging of Photoinduced Interfacial Charge Separation Geometries in Organic Photovoltaic Cell

The organic photovoltaic (OPV) devises have recently attracted much attention as the next generation thin-film solar cells that can be low-cost, flexible and light compared to the conventional silicon solar cells. The spin coating method from mixed solutions consisting of conjugate polymers as the electron donors (D) and fullerene derivatives as the acceptors (A) are employed to produce the solid photoactive layer of the OPV cells. Recent progresses in the organic materials and in device structures have enabled the remarkably efficient OPV cells as high as 12 % in the light energy conversion efficiency, which is however still lower than that in the silicon solar cells. In the organic photoactive layers, it is well known that the molecules tend to be self-organized to form the phase segregation by the polymers and by the fullerene derivatives to generate the bulk heterojunction (BHJ) by the domain interfaces. The BHJ thin-films composed of poly(3-alkylthiophene) (P3AT) and [6,6]-C61-butyric acid methyl ester (PC60BM) have been regarded as a standard and representative material of the photoactive layer in the OPV devices. Extensive studies have been performed to investigate the physical and photochemical properties of the OPV-related materials. The ultrafast photoinduced charge-injection dynamics has been clarified by the light-excitations of poly(3-hexylthiophene-2,5-diyl) (P3HT) domains in the P3HT:PCBM blend films. Recent studies have demonstrated that the photoinduced, contact charge-transfer (CT) states are initially generated at the D/A domain-interfaces and play significant roles on the photocurrent generations in the P3AT:PCBM blends. Thus, the electrons and holes need to escape from the Coulomb attraction which energy is supposed to be several hundreds of meV in the CT state. To elucidate why and how the photo-carriers escape from the CT binding, it is important to directly observe not only the separation distances between the electron and the hole but also the relative molecular positions and orientations of the charged species just after the interfacial charge conductions. As for such separated electron-hole pairs, the electronic coupling matrix elements (V CR) are key interaction to understand how the energy-wasting charge-recombination (CR) processes are inhibited. Connection between the geometry and the V CRin the CS state will also lead to unveiling 1) the initial photoconduction pathways in the molecular orbitals and 2) the electronic conduction characteristics relating to the trap-depth at the D/A domain interface.[1] The molecular motion in the organic semiconductors is another key to the efficient dissociation. The molecular libration in the blend should enhance the entropy of the dissociated CS state as compared to that of the bound CT state. [2] The time-resolved electron paramagnetic resonance (TREPR) spectroscopy is a powerful tool to detect unpaired spins and to investigate their electronic structures, geometries and dynamics.[1,2] In our previous studies, the geometries and the V CRvalues were reported for the interfacial CS states in the BHJ blend films at cryogenic temperature.[1] These distant CS states separated by c.a. 2 nm were hypothesized to be shallow traps that are weakly bound by the electrostatic attraction between delocalized charges. However, the properties of the electronic states and of the charge motions are unknown in those separated charges. In the present study, we have developed a three-dimensional mapping tool of the “electron spin polarization imaging method” obtained by quantum mechanical analysis of the TREPR signals to clarify precise charge geometries in the distant CS states.[3] We herein show directional charge-separation dynamics and motions at the domain interfaces in an organic solar cell composed of ITO(150 nm)/PEDOT:PSS(~40 nm)/P3HT:PCBM (~160 nm)/LiF(0.6 nm)/Al(100 nm) by using the spin polarization imaging map. [1] Kobori, Y.; Miura, J. Phys. Chem. Lett. 2015, 6, 113-123. [2] Miura, T.; Tao, R.; Shibata, S.; Umeyama, T.; Tachikawa, T.; Imahori, H.; Kobori, Y. J. Am. Chem. Soc. 2016, 138, 5879-5885. [3] Hasegawa, M.; Nagashima, H.; Minobe, R.; Tachikawa, T.; Mino, H.; Kobori, Y. J. Phys. Chem. Lett. 2017, 8, 1179-1184.