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Light utilization in organic solar-power-integrated greenhouses (A) Overview of an OSC-integrated greenhouse indicating spectral use of sunlight. (B) Absorption spectra of chlorophyll a (Chl a) and active layer of an OSC indicating complimentary absorption. (C) Schematic flowchart indicating distribution of sunlight toward management of plant growth, electricity generation, and greenhouse temperature management.
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Adding semitransparent organic solar cells (ST-OSCs) to a greenhouse structure enables simultaneous plant cultivation and electricity generation, thereby reducing the greenhouse energy demand. However, there is a need to establish the impact of such systems on plant growth and indoor climate and to optimize system tradeoffs. In this work, we consid...
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... lower the energy footprint of greenhouses, there has been growing interest in integrating solar cells onto the greenhouse structure, as illustrated in Figure 1. [7][8][9][10][11] In this approach, a portion of light is captured by the solar cells to generate power, while the remaining light transmits into the greenhouse for crop production. ...
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... may be applied that manage near-IR (NIR) solar radiation that contributes significant thermal energy, and coatings that manage long-wavelength (LW) IR that assist in maintaining indoor greenhouse temperatures. Thus, for solar power-integrated greenhouses to be successful, a holistic perspective that takes into account the opportunities and trade-offs between power generation, crop productivity, and greenhouse thermal management is needed, as illustrated in Figure 1. ...
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... Lettuce also has a reasonably short vegetative period, allowing for multiple replications in a reasonably short period. 28 The OSC filters were composed of high-performance active layers, namely FTAZ:IT-M, FTAZ:PC 71 BM and PTB7-TH:IEICO-4F, 15,29,30 as shown in Figure S1. The active layers were combined with PEDOT:PSS filters to mimic the optical properties of functional solar cells. ...
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... comparison, FTAZ:IT-M has an average drop in dry weight of 12%. If only considering R3, which has slightly higher PPFD (1,000 mmol m À2 s À1 as opposed to 800 mmol m À2 s À1 in R1 and R2) incident on the growth boxes, the dry weights for all 3 filters are found to be statistically similar to the control (Fig- ure S11). LA and leaf number normalized with respect to the control and averaged across all three rounds are provided for final harvest in Figures S11C and S11D, showing similar behavior for each treatment. ...
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... only considering R3, which has slightly higher PPFD (1,000 mmol m À2 s À1 as opposed to 800 mmol m À2 s À1 in R1 and R2) incident on the growth boxes, the dry weights for all 3 filters are found to be statistically similar to the control (Fig- ure S11). LA and leaf number normalized with respect to the control and averaged across all three rounds are provided for final harvest in Figures S11C and S11D, showing similar behavior for each treatment. Harvest pictures from R2 and R3 are provided in Figures S12 and S13. ...
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... stomatal conductance is a measure of stomata aperture enabling uptake of CO 2 as well as evaporation of H 2 O and controls overall plant performance. 34,35 The total chlorophyll a (chl a) concentration and the chlorophyll a/b (chl a/b) ratio in the lettuce is given in Figure 3E and the total chlorophyll b (chl b) concentration is shown in Figure S14. The chl a content and the a/b ratio is statistically comparable between lettuce grown under all three OSC treatments with respect to the control. ...
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... increase in LA is attributed to a higher partitioning of the assimilated CO 2 into the leaves. 39,40 Across all of the replications, lettuce grown under the FTAZ:IT-M treatment have an average LA that is $15% higher than the control ( Figure S11). FTAZ:IT-M had the lowest transmittance among the three OSC filters in the PAR region and is correlated with the filter treatment resulting in the greatest LA. ...
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... an example, we experimentally demonstrate the use of solution-processed DBRs that consist of alternating layers of a titanium oxide hydrate:poly(vinyl alcohol) hybrid material and poly(methyl methacrylate) (PMMA). Two DBRs were considered, with DBR-A having a stopband centered at 560 nm and DBR-B having a stopband centered at 745 nm, with transmittance shown in Figure S15. The transmission of the ST-OSC combined with DBR-A and -B is shown in Figure 4A, while the current voltage characteristics of the ST-OSC with the DBRs are shown in Figure 4B. ...
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... is then added to the ST-OSC device with FTAZ:IEICO-4F:PC 71 BM as the active layer following a device architecture described previously. The modeled device architecture is shown in Figure S16. The simulated electric field intensity (jEj2) as a function of thickness of the OSC device stack is provided in Fig- ure S17 for a wavelength in the PAR and IR region to illustrate DBR function. ...
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... The estimated solar power conversion efficiency was between 8.1-10.2% [9]. This research project aims to develop a method for mitigating thermal gain in greenhouses situated in hot climates. ...
The use of agricultural greenhouses in hot climates requires transparent enclosures to enable cooling for optimal plant growth. However, the cooling process incurs high water and energy costs due to solar gain and heat trapping. To address this issue, a novel enclosure design featuring a layer of liquid or water solution between two commercial grade glass layers has been proposed. This water solution absorbs thermal radiation and can be circulated through an active heat dissipation system. Carefully selected dyes can also be added to enhance water filter performance, allowing sufficient photosynthetically active radiation (PAR) through to the plants while blocking more of the non-PAR radiation.
To evaluate the efficiency of the proposed filter, a shading filter was used as a benchmarking scheme. The tests were conducted using clear water, mineral oil, and water with four commercially available pigments. Results indicated a reduction in the thermal load ranging from 31-62%, while the reduction in the photosynthetically active portion of the solar spectrum ranged from 32-79%. The clear water filter performed the best, blocking 45% of the thermal load while allowing 69% of weighted PAR radiation. This allowed for an additional 14% of PAR radiation compared to an equivalent 45% transparent shading device.
This new liquid filter design is effective in reducing cooling costs for agricultural greenhouses in hot climates, while still allowing for optimal plant growth. The clear water filter was found to be the most effective in blocking non-PAR radiation while still allowing sufficient PAR for the plants. However, there is potential for future work to identify additives that could enhance the filter’s overall performance. Engineering and technoeconomic development should be pursued to implement this technology for practical use in the field.
... These cells are seen in Figure 2. In recent years, this technology has begun to become readily available and can be found being sold commercially with options of varying transparency levels. Researchers such as [23] are beginning to explore how these can be used in agriculture and if the partial obstruction of sunlight affects the growth of leafy vegetables. As observed in his study, the impact is negligible. ...
In Singapore's limited land space, hydroponics, a soil-free method of that uses irrigation gained popularity for urban farming. Vertical farming can be made more sustainable by integrating Internet-of-Things (IoT) and solar photovoltaic (PV) as an intelligent system. This study aims to conduct a feasibility study on using PV cells to reduce energy consumption in IoT-enabled irrigation control and monitoring systems. In the experiment, an intelligent water irrigation system was designed for data collection including energy harvested from PV, climate conditions, and water quality. It was observed that a 45 Watt peak (Wp) solar PV was able to produce up to 460-watt hours of stored electricity in a day which can power a standalone hydroponic system that consists of a 19 W water pump and light emitting diode (LED) grow lights rated at 14 W/m. The climate monitoring system matched meteorological data from online sources proving to be applicable in the prototype. Water conditions such as water temperature and electrical conductivity (EC) also correlate to readings taken from traditional handheld water quality testers. Based on the fabricated prototype, integration is deemed to be feasible using power harvested from the sun.
... Integrating semi-transparent PV modules into a greenhouse structure is a proposed approach in agrivoltaics for simultaneous plant cultivation and electricity generation, with the added benefit of reducing greenhouse energy demand [24]. Semi-transparent organic solar cells are primarily explored for this application, leveraging the tunable absorption characteristics of the active materials [25][26][27][28]. Alternatively, the desired spectral allocation can be achieved with inorganic thin-film solar cells through engineered multilayer designs of the back reflecting contact [29]. ...
The integration of photovoltaic technologies within the agricultural framework, known as agrivoltaics, emerges as a promising and sustainable solution to meet the growing global demands for energy and food production. This innovative technology enables the simultaneous utilization of sunlight for both photovoltaics (PV) and photosynthesis. A key challenge in agrivoltaic research involves identifying technologies applicable to a wide range of plant species and diverse geographic regions. To address this challenge, we adopt a multi-experimental and multi-species approach to assess the viability of semi-transparent, spectrally selective thin-film silicon PV technology. Our findings demonstrate compatibility with crop production in controlled environments for both plants and algae. Notably, selective thin-film PV exhibits the potential to enhance crop yields and serves as a photo-protectant. We observe that plant and algal growth increases beneath the selective PV film when supplemented with appropriate diffuse light in the growth environment. Conversely, in situations where light intensity exceeds optimal levels for plant growth, the selective PV film provides a photo-protective effect. These results suggest potential supplementary benefits of employing this technology in regions characterized by excessive light irradiation, where it can contribute to healthy plant growth.
... However, some of these solutions are still constrained by small PV size, low transparency, and lack of flexibility to tune the transmission spectra (Table S1). Consequently, their impact on plant growth remains disputed (Ravishankar et al., 2021;Song et al., 2020;Thompson et al., 2020;Zisis et al., 2019). More importantly, these pioneering works largely focus on PV materials and characterization (Table S1), disregarding plant performance and yields (Dessì et al., 2020;Shi et al., 2019;Subhani et al., 2019;Weng et al., 2021). ...
... Evaluations of plant growth often rely on oversimplified models, such as the crop growth factor G (Wang, D. et al., 2021a) or other simplified models (Ravishankar et al., 2022). Although some studies have experimentally evaluated plant growth, they are usually qualitative Ravishankar et al., 2021;Song et al., 2020;Wang, D. et al., 2021a). Several recent studies have reported photosynthetic performance under PV shade (Zhang et al., 2024) or split sunlight (Yuan et al., 2023), but in situ measurements in ambient light conditions were not mentioned. ...
Spectral splitting is a promising strategy for wavelength-selective solar energy harvesting, offering the potential to combine photosynthesis with artificial solar technologies for higher hybrid efficiencies. Despite this potential, the photosynthetic performance and biomass production of plants under split sunlight has remained unclear. Photosynthetic organisms under full sunlight must dissipate excess absorbed light energy as heat, resulting in suboptimal photosynthetic efficiency. Here, we show that solar spectral splitting can enhance photosynthesis and yield while utilizing excess sunlight for energy polygeneration. Specifically, we observed increased electron transport rate (22 %), daily leaf photosynthetic CO 2 uptake (12 %), and plant biomass productivity (up to 136 %) under the selected solar spectral bands, largely due to decreased photoinhibition and improved stomatal conductance. The theoretical limit and practical guideline for photovoltaic (PV) efficiency under complementary spectral bands were ~22.5 % and ~14.6 %, respectively, highlighting the substantial potential for energy production. This study provides a basis for the design and application of spectral splitting energy systems on agricultural lands, which not only encompasses the concept of sharing the land or the solar spectrum, but also presents an effective strategy for enhancing crop production.
... 13 With the emergence of PV cells of various materials and spectral filters, several researchers have studied SAPV systems. [14][15][16][17][18][19][20][21][22] However, these studies had focused on small-scale greenhouses and laboratory modules. The efficiency of these systems is notably lower than that of ordinary crystalline PVs, and there have been no systematic successful reports on large-scale construction, spectral microclimate, or spectral agricultural planting results. ...
Agrivoltaics (AV) offers a promising solution to address both food and energy crises. However, crop growth under photovoltaic (PV) conditions faces substantial challenges due to insufficient light transmission. We propose a large-scale and cost-effective spectral separated concentrated agricultural photovoltaic (SCAPV) system. The system utilizes concentrator modules, cell components, and dual-axis tracking systems to enhance power conversion efficiency (PCE), achieving a maximum PCE of 11.6%. After three years of successful operation, a 10 kWp power plant achieved an average annual electricity generation exceeding 107 MWh/ha. The results showed higher yields of various crops, including ginger and sweet potatoes, and significant improvements in soil moisture retention compared to open air. The improvements in PCE and microclimate validate the scalability of the SCAPV, which provides better plant conditions and cost effectiveness, with an estimated cost reduction of 18.8% compared to conventional PV power plant. This study provides valuable insights and directions for improvement in AV.
... Single crystal Si cells have turned into an economically viable sustainable energy harvesting solution, featuring PCEs of over 25% and long-term stability of 25 + years at costs that have steadily declined in the past decade 8,9 . Besides utility-scale power generation, they serve off-grid applications such as parking meters, portable chargers, or street lights and can be integrated into buildings, greenhouses or vehicles, and serve electricity generation, water and waste water treatment in developing countries [10][11][12][13][14][15][16][17][18] . In addition to that, solar cells remain crucial for space applications and they are used on the International Space Station (ISS) or to power moon and mars rangers 19,20 . ...
The term 'Solar Cell’ is commonly used for Photovoltaics that convert light into electrical energy. However, light can be harvested from various sources not limited to the Sun. This work considers the possibility of harvesting photons from different star types, including our closest neighbor star Proxima Centauri. The theoretical efficiency limits of single junction photovoltaic devices are calculated for different star types at a normalized light intensity corresponding to the AM0 spectrum intensity with AM0 = 1361 W/m². An optimal bandgap of > 12 eV for the hottest O5V star type leads to 47% Shockley-Queisser photoconversion efficiency (SQ PCE), whereas a narrower optimal bandgap of 0.7 eV leads to 23% SQ PCE for the coldest red dwarf M0, M5.5Ve, and M8V type stars. Organic Photovoltaics (OPVs) are the most lightweight solar technology and have the potential to be employed in weight-restricted space applications, including foreseeable interstellar missions. With that in mind, the Sun’s G2V spectrum and Proxima Centauri’s M5.5Ve spectrum are considered in further detail in combination with two extreme bandgap OPV systems: one narrow bandgap system (PM2:COTIC-4F, Eg = 1.14 eV) and one wide bandgap system (PM6:o-IDTBR, Eg = 1.62 eV). Semi-empirically modeled JV-curves reveal that the absorption characteristics of the PM2:COTIC-4F blend match well with both the G2V and the M5.5Ve spectrum, yielding theoretical PCEs of 22.6% and 12.6%, respectively. In contrast, the PM6:o-IDTBR device shows a theoretical PCE of 18.2% under G2V illumination that drops sharply to 0.9% under M5.5Ve illumination.
... In this wa building can convert solar energy into electricity. [7][8][9][10][11][12][13]. ...
... Interestingly, only 50% of the electricity generated in this system was consumed by the greenhouse (for lettuce cultivation) in hot climate conditions, leaving the remaining 50% of electricity available for storage. Additionally, it was observed that in mixed humid weather conditions, energy consumption by the greenhouse was higher, yet the produced energy remained in surplus [10,11,107]. ...
... O'Connor et al. [11] also showcased an OSC featuring an active material layer with absorption properties that complemented the absorption of chlorophyll in red leaf lettuce. The fresh and dry weights of red leaf lettuce cultivated under semitransparent OSCs were comparable to those of the control treatment. ...
Organic solar cells offer benefits such as transparent characteristics, affordability in manufacturing, and the ability to tailor light absorption properties according to specific needs. This review discusses challenges and recent strategies to enhance the power conversion efficiency of organic solar cells, such as bandgap tuning, molecular orbital alignment, active layer morphology engineering, electron-donating and -withdrawing group incorporation, side chain length engineering, a third additive’s insertion, and control of the solubility of materials. The good transparency of organic solar cells makes them ideal for greenhouse-integrated photovoltaics applications. By efficiently absorbing sunlight for photosynthesis and clean energy production, transparent organic solar cells optimize light management, enhance energy efficiency, and minimize overheating risks, resulting in more sustainable and efficient greenhouse operations. This review also evaluates organic solar cell integration in the greenhouse. The implementation of the strategies explored in this review can significantly impact a wide range of performance parameters in organic solar cells. These parameters include the optoelectronic properties, absorption spectrum, open circuit voltage, exciton dissociation, charge transport, molecular packing, solubility, phase separation, crystallinity, nanoscale morphology, and device stability. An optimized organic solar cell design is particularly beneficial for greenhouse-integrated photovoltaics, as it ensures efficient energy conversion and energy management, which are crucial factors in maximizing the performance of the greenhouse.
... The sensors equipped with the nodes of IoT gather the relevant data from the environment and help to maintain the balanced agricultural ecosystem. Alternate energy sources are necessary for sustainable smart agricultural farming to create a highintensity environment without creating an energy demand [14,15]. ...
... Although most studies have focused on understanding how new spectrally selective PV technologies affect both plant and power generation at the lab or greenhouse scales, 74,[76][77][78][79][80]82 recent investigations in the context of AV farms are emerging. 60,83 This is the case of SCAPVs, which can be implemented using low-cost components and are capable of transmitting photons within the PAR wavelength for photosynthesis while reflecting the remaining spectrum for electricity generation. ...
... The semi-transparent, ultra-light, and less light-sensitive modules were attached to the inside and outside of the greenhouse. OPV offer the option to select the wavelengths the plant needs to be transmitted and the remaining wavelengths to be converted into electricity [111], such that highly transparent organic solar cells allow the visible light, which is used by the plants, to pass through and use the infrared portion to generate electricity, in order to replace foil covers above plants and reduce plastic waste problems [112]. ...
Climate change and land use conflicts represent two of the greatest challenges worldwide. Climate change affects agricultural production by more frequent and more intense extreme weather events besides the continuing temperature and carbon dioxide increase. The most important climate mitigation measure is the abolishment of fossil fuels, and climate change adaptation is needed for sustainable crop production. The concept of agrivoltaics (AV) combines the installation of a photovoltaic (PV) system for clean energy generation with an agricultural use on the same area, increasing land use efficiency and creating synergy effects to adapt agriculture to climate change by protecting crops from extreme weather events. Recently, interest in AV systems is booming in many countries with an estimate 14 GW of electricity being produced by AV worldwide. Latest technical options of AV systems are described, and the advantage for crops is evaluated. Additionally, environmental effects are reviewed, in terms of influences on microclimate, biodiversity, soil conditions and water management. Optimal technical options for installation and management of AV and results of life cycle analyses are presented. Economic comparison showed that if electricity is directly consumed on-farm, an amortization could be achieved after 3.22 years, based on the present electricity costs in Germany.
