Organic Solar Modules Research Articles

CO2 snow jet cleaning as a roll-to-roll compatible method for deburring IMI substrates after laser patterning

Burring is commonly encountered upon patterning of dielectric-metal-dielectric (DMD) transparent electrodes by laser ablation. These burrs are conductive and thus lead to shunting of the (opto-)electronic devices built upon these electrodes. In this work, CO2 snow jet blasting is presented as a convenient and reliable method for deburring laser-patterned DMD electrodes during roll-to-roll manufacturing of organic solar modules. As CO2 snow jet blasting significantly reduces the extent of shunting and concomitantly avoids scratching the electrode, the photoelectrical conversion efficiencies of the solar modules thus produced are higher than those obtained for traditional deburring techniques.

Improved Molecular Ordering in a Ternary Blend Enables All-Polymer Solar Cells over 18% Efficiency.

Although all-polymer solar cells (all-PSCs) show great commercialization prospects, their power conversion efficiencies (PCEs) still fall behind their small molecule acceptor-based counterparts. In all-polymer blends, the optimized morphology and high molecular ordering are difficult to achieve since there is troublesome competition between the crystallinity of the polymer donor and acceptor during the film-formation process. Therefore, it ischallenging to improve the performance of all-PSCs. Herein, a ternary strategy is adopted to modulate the morphology and the molecular crystallinity of an all-polymer blend, in which PM6:PY-82 is selected as the host blend and PY-DT is employed as a guest component. Benefiting from the favorable miscibility of the two acceptors and the higher regularity of PY-DT, the ternary matrix features a well-defined fibrillar morphology and improved molecular ordering. Consequently, the champion PM6:PY-82:PY-DT device produces a record-high PCE of 18.03%, with simultaneously improved open-circuit voltage, short-circuit current and fill factor in comparison with the binary devices. High-performance large-area (1 cm2 ) and thick-film (300nm) all-PSCs are also successfully fabricated with PCEs of 16.35% and 15.70%, respectively.Moreover, 16.5cm2 organic solar module affords an encouraging PCE of 13.84% when using the non-halogenated solvent , showing the great potential of "Lab-to-Fab" transition of all-PSCs.

26.75 cm2 organic solar modules demonstrate a certified efficiency of 14.34%

26.75 cm2 organic solar modules demonstrate a certified efficiency of 14.34%

Integration of body-mounted ultrasoft organic solar cell on cyborg insects with intact mobility

Cyborg insects have been proposed for applications such as urban search and rescue. Body-mounted energy-harvesting devices are critical for expanding the range of activity and functionality of cyborg insects. However, their power outputs are limited to less than 1 mW, which is considerably lower than those required for wireless locomotion control. The area and load of the energy harvesting device considerably impair the mobility of tiny robots. Here, we describe the integration of an ultrasoft organic solar cell module on cyborg insects that preserves their motion abilities. Our quantified system design strategy, developed using a combination of ultrathin film electronics and an adhesive–nonadhesive interleaving structure to perform basic insect motion, successfully achieved the fundamental locomotion of traversing and self-righting. The body-mounted ultrathin organic solar cell module achieves a power output of 17.2 mW. We demonstrate its feasibility by displaying the recharging wireless locomotion control of cyborg insects.

High‐Performance Organic Solar Modules via Bilayer‐Merged‐Annealing Assisted Blade Coating

Although encouraging progresses being made on the spin-coated prototype cells, organic solar cells still face significant challenges, yet to be explored, for up-scaling the multi-stacked photoactive layers in the construction of large area modules. Herein, high-performance opaque and semitransparent organic solar modules are developed via a bilayer-merged-annealing (BMA) assisted blade-coating strategy, achieving the impressive efficiencies of 14.79% and 12.01% with respect to active area of 18.73 cm2 , which represent the best organic solar minimodules so far. It is revealed that BMA strategy effectively resolves the de-wetting issues between polar charge transport layer solution and non-polar bulk heterojunction blends, hence improving the film coverage, along with electronic and electric contacts of multi-stacked photoactive layers. As results, organic solar modules coated under ambient condition successfully retain the high-efficiency of small area cells upon 312 times area scaling-up. Overall, this work provides a facile and effective method to fabricate high-performance organic solar modules under ambient condition. This article is protected by copyright. All rights reserved.

Fluid Mechanics Inspired Sequential Blade‐Coating for High‐Performance Large‐Area Organic Solar Modules

AbstractDespite rapid advances in the field of organic solar cells (OSCs), high‐performance large‐scale OSC modules are limited. In this study, it is found that the non‐Newtonian fluid feature of conjugated polymer primarily causes the wedge‐shaped mass (donor and/or acceptor component)/phase distribution of blends in large‐scale blade coating, which results in the lower module efficiency. To address the critical issue in printing manufacturing, a reversible and sequential layer‐by‐layer (RS‐LBL) deposition method with sequential twice forward/reverse blade‐coating of polymer donor and forward blade‐coating of Y6 acceptor, is developed for precisely controlling fluid mechanics of PM6:Y6 active layer. Through using the RS‐LBL strategy, uniform morphology and favorable phase separation and crystallization are obtained in the 10 × 10 cm2 active layer. As a result, the RS‐LBL‐based OSCs show excellent operational stability, and an outstanding PCE of 13.47% is achieved with significantly suppressed charge recombination losses in the 36 cm2 large‐area OSC module, which represents the highest efficiency of binary solar modules with the area over 30 cm2. This study provides a feasible route for the next generation of high‐performance large‐area OSCs and OSC modules.

High-performance see-through power windows

High-performance see-through power windows, derived from newly designed semitransparent organic solar modules, exhibit excellent energy generation and saving features.

Large‐Area Organic Solar Modules with Efficiency Over 14%

AbstractIt is still challenging to fabricate efficient large‐area organic solar modules by solution processing. Processing window is important to obtain optimal aggregation of an active layer in large area for high efficiency. The star active layer of PM6:Y6 is processed from chloroform (for high efficiency) that has a narrow processing window due to the low boiling point of the solvent. In this work, the correlation between chemical structure (side chains) and processing solvents is investigated to obtain high efficiency and long processing windows. It is found that large side chains on the pyrrole ring are the key factor influencing the aggregation of active layer films. Short side chain (in Y6 and Y6‐1O) will cause excess aggregation when processed from high‐boiling‐point solvent (chlorobenzene, CB), while long side‐chain (in BTP‐BO‐4F, BTP‐BO‐4Cl, and BTP‐eC9) can inhibit such aggregation and maintain high photovoltaic performance when processed from CB with wide processing window. In the end, over 25 cm2 organic solar module via doctor blading based on PM6:BTP‐eC9 active layer has been fabricated with a PCE of 14.07%.

Fully printed organic solar modules with bottom and top silver nanowire electrodes

AbstractOne of the advantages of organic photovoltaics (OPV) over other contemporary technologies is its relative ease of processing. There are, however, very few works that have realized fully printed devices, including the bottom electrode, let alone with a scalable process in a reasonable device size (>1 cm2). In this work, design steps and optimization processes towards fully printed OPV modules with scalable processes are demonstrated for the first time. An overview on issues related to upscaling with printed electrodes is first provided. The various issues are then addressed by a rational design process supported by measurements and calculations. Finally, a set of fully printed OPV modules are fabricated using these optimized parameters that have over 3.5‐cm2 active area with 5% efficiency. For the first time, this work has also demonstrated the process compatibility of fully printed device structures with non‐fullerene acceptor systems, which enables more design opportunities for the current generation of high‐performance OPV materials.

Highly Reflective and Low Resistive Top Electrode for Organic Solar Cells and Modules by Low Temperature Silver Nanoparticle Ink

One of the issues that have caused a wide performance gap between commercially available organic photovoltaic (OPV) modules and the hero cells in literature lies in the lack of printable and roll‐to‐roll process compatible high‐performance top electrodes. This work takes an unorthodox approach to this issue by developing a printable silver nanoparticle (AgNP) film top electrode that can achieve a similar performance as evaporated ones (EvapAg). It illustrates the developmental process from ink formulation to the critical processing conditions that are tailored for OPV devices procedurally. The resultant cells and modules with AgNP electrodes have achieved almost the same power conversion efficiencies (≈90%) as those with evaporated silver electrodes, as demonstrated for multiple material systems, printing methods, as well as layouts. Under low light condition, AgNP cells perform even significantly better than EvapAg ones, due to their lower leakage currents. More importantly, this work has demonstrated that fully printed OPV modules can achieve similar performance as small scale OPV cells with evaporated electrodes when both the electrical and optical performance of their top electrodes are comparable. With the latest generation of materials, this approach offers an attractive alternative for manufacturing of highly efficient OPV modules at large scale.

Portable Photovoltaic-Self-Powered Flexible Electrochromic Windows for Adaptive Envelopes

Variable transmission applications for light control or energy saving based on electrochromic materials have been successfully applied in the past in the building, sports, or automotive fields, although lower costs and ease of fabrication, installation, and maintenance are still needed for deeper market integration. In this study, all-printed large area (900 cm2 active area) flexible electrochromic devices were fabricated, and an autoregulating self-power supply was implemented through the use of organic solar cells. A new perspective was applied for automotive light transmission function, where portability and mechanical flexibility added new features for successful market implementation. Special emphasis was placed in applying solution-based scalable deposition techniques and commercially available materials (PEDOT-PSS as an electrochromic material; vanadium oxide, V2O5, as a transparent ion-storage counter electrode; and organic solar modules as the power supply). A straightforward electronic control method was designed and successfully implemented allowing for easy user control. We describe a step-by-step route following the design, materials optimization, electronic control simulation, in-solution fabrication, and scaling-up of fully functional self-powered portable electrochromic devices.

19.34 cm2 large-area quaternary organic photovoltaic module with 12.36% certified efficiency

In this study, a quaternary blending strategy was applied in the fabrication of organic photovoltaic devices and large-area modules. As a result, the ultimate quaternary organic solar cells (OSCs) deliver 16.71% efficiency for small-area devices and 13.25% for large-area ( 19.34 cm 2 ) modules (certified as 12.36%), which is one of the highest efficiencies for organic solar modules to date. Our results have proved the synergistic effects of multiple components in OSCs, providing an effective strategy for achieving high-performance organic photovoltaic devices and modules.

Design of novel thiazolothiazole-containing conjugated polymers for organic solar cells and modules

One of the major challenges in the field of organic photovoltaics is associated with high-throughput manufacturing of efficient and stable organic solar cells. Practical realization of technologies for production of large-area organic solar cells requires the development of novel materials with a defined combination of properties ensuring sufficient reliability and scalability of the process in addition to good efficiency and operation stability of the devices. In this work, we designed two novel polymers comprising thiazolothiazole units and investigated their performance as absorber materials for organic solar cells and modules. Optimized small-area solar cells based on P1/[70]PCBM ([6,6]-phenyl-C71-butyric acid methyl ester) blends exhibited promising power conversion efficiency (PCE) of 7.5%, while larger area modules fabricated using slot die coating showed encouraging PCE of 4.2%. Additionally, the fabricated devices showed promising outdoor stability maintaining 60–70% of the initial efficiency after 20 sun days being exposed to natural sunlight at the Negev desert. The obtained results feature the designed polymer P1 as a promising absorber material for a large-scale production of organic solar cells under ambient conditions.

Slot-die processing and encapsulation of non-fullerene based ITO-free organic solar cells and modules

Organic photovoltaic (OPV) devices have shown remarkable performance progress in recent years, reaching current record power conversion efficiency (PCE) values of 16.4% for single junction and 17.3% for multi junction devices, owing mostly to the impressive developments made within synthesis of new non-fullerene acceptors. This progress places organic solar cells at the forefront of thin-film photovoltaic technology. However, in order to meet industrial demands and reach high performance values in industrial settings, further research and development efforts within roll-to-roll (R2R) and sheet-to-sheet (S2S) processing of OPV devices under ambient conditions are required. Furthermore, OPV modules being manufactured through such up-scaled processing techniques should ideally be developed from low cost materials, and show good stability towards various different operational stress conditions. In this work, we demonstrate combined R2R and S2S development of ITO-free OPV devices, which are based on the non-fullerene material system PBDB-T:ITIC. The devices are processed from R2R vacuum sputtering and S2S slot-die coating at ambient conditions, and reach cell PCE values of 5.5%. In addition, we introduce a correlation between different barrier films, both commercial and sputtered inorganic coatings on ultra-clean PET, and the lifetime of the developed devices. The results therefore demonstrate an important step in the development of OPV devices from R2R and S2S processes in industrial settings.

Investigation of performance of P3HT:PCBM organic photovoltaic module under real operating conditions

In this work the behavior of an organic solar module operating under real solar radiation conditions is presented. This allows to understand which parameters limit the efficiency of an organic device and their underlying mechanisms. The characterization of a module, produced by CSEM Brasil, with active layer P3HT:PCBM, is based on instantaneous voltage and current curves, dark current curves and analysis of the module operating continuously with fixed voltage. This allows to extract the parameters of the equivalent circuit of the module, such as diode saturation current (I0), series resistance (RS) and shunt resistance (RSH) as well as to understand the influence of different levels of radiation and temperature on such parameters. The work presented was performed by using a commercial organic solar module in extensive outdoor experiments. The results are based on continuous use and for several levels of radiation and temperature under real operating conditions in comparison with a theoretical model for the first time. With the continuous tests it was possible to demonstrate the average daily generation of the module in Wh/m2, and also to verify experimentally, that the module presents better efficiency for diffuse radiation.

P3HT Molecular Weight Determines the Performance of P3HT:O‐IDTBR Solar Cells

Large‐scale production of organic solar modules requires low‐cost and reliable materials with reproducible batch‐to‐batch properties. In case of polymers, their (photo)physical properties depend strongly on the polymers’ molecular weight (MW). Herein, the impact of the MW of the donor polymer poly(3‐hexylthiophene) (P3HT) on the photophysics is studied in blends with a recently developed rhodanine‐endcapped indacenodithiophene nonfullerene acceptor (IDTBR), a bulk heterojunction (BHJ) system that potentially fulfills the aforementioned criteria for large‐scale production. It is found that the power conversion efficiency (PCE) increases when the weight‐average MW is increased from 17 kDa (PCE: 4.0%) to 34 kDa (PCE: 6.6%), whereas a further increase in MW leads to a reduced PCE of 4.4%. It is demonstrated that the charge generation efficiency, as estimated from time‐delayed collection field experiments, varies with the P3HT MW and is the reason for the differences in photocurrent and device performance. These findings provide insight into the fundamental photophysical reasons of the MW dependence of the PCE, which is taken into account when using polymer‐based nonfullerene acceptor blends in solar cell devices and modules.

Design, Electrical, and Optical Modelling of Bulk Heterojunction Polymer Solar Cell

The energy scenario today is focused on the development and usage of solar cells, especially in the paradigm of clean energy. To readily create electron and hole pairs, solar cells utilize either photoactive or photosensitive components. A bulk heterojunction (BHJ) is a nanolayer consisting of donor and acceptor components with a large interpenetrated acceptor and donor contact area. In this context, a mix of P3HT and PCBM offers novelty for its use as an acceptor as well as a donor. In the work presented here, we address the mechanism of modelling and characterization of a BHJ-based polymer solar cell. Here, a new design of BHJ polymer solar cells have been designed, modelled, using Silvaco TCAD in the Organic Solar module, and matched with an already assembled device having similar features. Using this model, we have been able to estimate key parameters for the modelled devices, such as the short-circuit current density, open-circuit voltage, and fill factor with less than 0.25 error index compared to the fabricated counterpart, paving the way for fabless polymer solar cell design and optimization.

A Cost Analysis of Fully Solution‐Processed ITO‐Free Organic Solar Modules

AbstractOrganic photovoltaics (OPVs) have become a potential candidate for clean and renewable photovoltaic productions. This work examines the current cost drivers and potential avenues to reduce costs for organic solar modules by constructing a comprehensive bottom‐up cost model. The direct manufacturing cost (MC) and the minimum sustainable price (MSP) for an opaque single solar module (SSM) (MC = 187 ¥ m−2, MSP = 297 ¥ m−2) and for a tandem solar module (MC = 224 ¥ m−2, MSP = 438 ¥ m−2) are analyzed in detail. Within this calculation, the most expensive layers and processing steps are identified and highlighted. Importantly, the low levelized cost of energy (LCOE) value for an SSM with a 10% power conversion efficiency in a 20‐year range from 0.185 to 0.486 ¥ kWh−1, with a national average of 0.324 ¥ kWh−1 in China under an average solar irradiance of 1200 kWh m−2 year−1. Moreover, the impact on the cost of alternative materials and constructions, process throughputs, module efficiency, and module lifetime, etc., is presented and avenues to further reduce the MSP and LCOE values are indicated. The analysis shows that OPVs can emerge as a competitive alternative to established power generation technologies if the remaining issues (e.g., active layer material cost, module efficiency, and lifetime) can be resolved.

Effect of the Electron Transport Layer on the Interfacial Energy Barriers and Lifetime of R2R Printed Organic Solar Cell Modules.

Understanding the phenomena at interfaces is crucial for producing efficient and stable flexible organic solar cell modules. Minimized energy barriers enable efficient charge transfer, and good adhesion allows mechanical and environmental stability and thus increased lifetime. We utilize here the inverted organic solar module stack and standard photoactive materials (a blend of poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester) to study the interfaces in a pilot scale large-area roll-to-roll (R2R) process. The results show that the adhesion and work function of the zinc oxide nanoparticle based electron transport layer can be controlled in the R2R process, which allows optimization of performance and lifetime. Plasma treatment of zinc oxide (ZnO) nanoparticles and encapsulation-induced oxygen trapping will increase the absolute value of the ZnO work function, resulting in energy barriers and an S-shaped IV curve. However, light soaking will decrease the zinc oxide work function close to the original value and the S-shape can be recovered, leading to power conversion efficiencies above 3%. We present also an electrical simulation, which supports the results. Finally, we study the effect of plasma treatment in more detail and show that we can effectively remove the organic ligands around the ZnO nanoparticles from the printed layer in a R2R process, resulting in increased adhesion. This postprinting plasma treatment increases the lifetime of the R2R printed modules significantly with modules retaining 80% of their efficiency for ∼3000 h in accelerated conditions. Without plasma treatment, this efficiency level is reached in less than 1000 h.

Writable and patternable organic solar cells and modules inspired by an old Chinese calligraphy tradition

A fabrication technique inspired by an old Chinese calligraphy tradition is developed to fabricate organic solar cells and modules.