Semitransparent Photovoltaics Research Articles

Dye-Containing Polymers with π-Extened Diketopyrropyrrole Derivatives for Semi-Transparent Organic Photovoltaics.

Dye-containing polymers P1 (PEDPP-OT-BDT) and P2 (PEDPP-OT-BDTT) including a π-extended diketopyropyrrole (DPP) derivative and electron-rich thiophene fused ring units (4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b']dithiophene for P1 and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene for P2) were synthesized as narrow band gap dyes. A π-extended DPP (EDPP-OT-BrPh), fragment of the polymers P1 and P2, was obtained by extending the π-conjugation of DPP using Ru(III)-catalyzed C-H and N-H activation reported by Gońka et al. in 2019, exhibiting a high quantum yield (ϕem=0.84) and small HOMO-LUMO gap (Eg=1.69 eV) due to the spatial overlap of the HOMO and LUMO orbitals. The solubility of the π-extended DPP was improved by introducing four 2-octylthophene side chains around the periphery of the planer dye moiety, while maintaining the high planarity of the dye molecule, which is essential to the function of optoelectronic devices. As a result, P1 and P2, polymerized with the π-extended DPP and BDT derivatives, exhibit carrier mobility of approximately 10-5 cm2/Vs in organic field-effect transistors (OFETs). In bulk heterojunction (BHJ) solar cells with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), they demonstrate a power conversion efficiency (PCE) of 1.0 % with an average transmittance (AVTs) of around 60 %.

Mitigating interfacial recombination enabling efficient semitransparent organic photovoltaics

Charge recombination at the interface between top electrode and active layer is a substantial current loss pathway in semitransparent organic photovoltaics (STOPVs). Reducing interfacial traps is an effective strategy to mitigate interfacial recombination and promote charge extraction, and thereby improve the power conversion efficiencies (PCEs). Herein, a facile approach of depositing 11-mercapto-undecanoic acid (11-MUA) on zinc oxide (ZnO) cathode interlayer in conventional STOPVs is demonstrated. 11-MUA can form covalent interactions with both ZnO and silver (Ag) and thus can induce the formation of high-quality ultrathin Ag electrode. Compared with that deposited on bare ZnO, the Ag electrode on ZnO/11-MUA shows higher conductivity as well as higher optical transparency. The STOPVs based on ZnO/11-MUA/Ag exhibit 2 orders of magnitude lower surface trap density than the counterparts based on ZnO/Ag. Consequently, 11-MUA simultaneously improves the PCEs from 11.2% to 12.1% and average visible transmittance from 21.6% to 27.0% in the STOPVs. Furthermore, arising from the 11-MUA-modified interface, the thermal stability of STOPVs based on ZnO/11-MUA/Ag is also improved.

An overview on building-integrated photovoltaics: technological solutions, modeling, and control

The advancement of renewable and sustainable energy generation technologies has been driven by environment-related issues, energy independence, and high costs of fossil fuels. Building-integrated photovoltaic systems have been demonstrated to be a viable technology for the generation of renewable power, with the potential to assist buildings in meeting their energy demands. This work reviews the current status of novel PV technologies, including bifacial solar cells and semi-transparent solar cells. This review discusses the various constructions of PV technologies, recent advances in these products, the influence of key design factors on electrical and thermal performance, and their potential in the design of energy-efficient smart buildings. The attention is focused on bifacial and semi-transparent PV systems, given the high level of interest of the scientific community in their current and potential applications.Focus is also devoted to the analysis of the electrical, optical, and thermal modeling procedures developed for sizing, designing, and integrating photovoltaics into larger building simulations. The development of these models has a positive impact on the implementation of next-generation smart buildings. The latest innovative developments and key issues in the application of bifacial PV solutions in buildings are also summarized and analyzed. Special attention is paid to rear side electrical performance, which can be evaluated by means of illuminance/optical backside modeling. Finally, energy management and control of PV-equipped buildings via both model-based and data-driven approaches are discussed, as well as the integration of electric storage systems in a multi-building context.

Algorithmic advancements in agrivoltaics: Modeling shading effects of semi-transparent photovoltaics

Radiation is a crucial factor in the field of agrivoltaics in greenhouses. Depending on the type of photovoltaics integrated into greenhouses, the effect on radiation varies through the phenomenon of shading. Shading in greenhouses can be either beneficial or detrimental, making its analysis imperative. In this study, the improvements and modifications made in an algorithm capable of calculating the shading from photovoltaic units installed in greenhouses are presented. A key modification to the algorithm is the calculation of shading from semi-transparent photovoltaic modules, in contrast to its original form, in which photovoltaic modules were considered opaque. The algorithm was validated using radiation data from pyranometers within a greenhouse. The coefficients used were Pearson's r correlation coefficient and the Coefficient of Variation. The correlation coefficients for times without shading effect approached the values for the case without photovoltaics installed on the roof. Simultaneously, based on the coefficients of variation, the uniformity of radiation within the shade was validated, thereby confirming its existence. Finally, the effect of semi-transparent photovoltaic units on Global Horizontal Irradiance and Photosynthetically Active Radiation was studied, with the reduction for the former approaching 52 % and about 60 % for the latter. These changes in radiation can be either beneficial or not, depending on the type of crop and the needs of the greenhouse, such as cooling.

(Invited) Silicon Nanocrystals and Electrum Nanoclusters with High Quantum Yield for Light Converting Applications

While QDs are typically made of semiconductors, metals at low dimensions also turn to discrete electronic structure. The characteristic transition size from bulk to nanodot is lower, because Fermi level position is at the band middle, while discretization of levels starts from the band edge. Therefore, only for sizes of a metal entity ~ 1 nm a QD-like behavior manifests.Here we show that metal nanoclusters Au16Ag7 of an electrum alloy (gold-silver) with adamantanethiolate ligands possess PL quantum yield of ~ 70% in a thiol-ene polymer matrix [1]. PL is in NIR range with a large Stokes shift. Due to parity-forbidden transition the PL lifetime is in microseconds. These characteristics are similar to silicon QDs, where optical transition is also partly forbidden. Luminescence from Si QDs (5-10 nm size) may also feature high quantum efficiency when a defect-free core with good surface passivation is prepared. We have demonstrated a new synthesis method, which can reduce precursor cost by an order of magnitude from the established HSQ-based technique [2]. Si QDs prepared in this way have near-unity internal and > 50% external (quantum yield) efficiency with a large Stokes shift. In both nanomaterials the re-absorption is suppressed, which is of value for several applications.One such application is a semi-transparent photovoltaics for glazing in building-integration. It is based on a luminescent solar concentrator concept, where high efficiency and a large Stokes shift are necessary requirements for nanophosphors. In this configuration absorbed solar light is re-emitted and a large fraction of it is guided by total internal reflection to the edges for collection by standard solar cells. As a proof-of-concept we fabricated 20x20 cm2 prototypes, where Si QD-doped polymer layer is sandwiched between glass plates in a triplex geometry. Such “solar windows” feature high transparency (>80%), low haze (<3%), high color rendering index (~ 88) and, at the same time, deliver up to 0.6 W of electrical peak power under one sun [3]. Original measurement techniques were developed to characterize large-area devices [4,5].

Exploration of benefits and performances of integration of semitransparent photovoltaics with buildings and infrastructure: A comprehensive review

AbstractThis article discusses how incorporating semitransparent photovoltaic (SPV) modules into buildings can reduce dependency on conventional energy sources, contributing to a shift toward renewable energy and self‐sustaining construction. It explores various ways to implement SPV technology in building and infrastructure design, and outlines the advantages, such as improved daylighting, thermal regulation, and energy efficiency. The analysis also considers how SPV integration affects energy and exergy performance, emphasizing its role in achieving net‐zero energy buildings. Additionally, the article identifies existing research gaps, providing guidance for future studies and practical applications in the building sector.

High‐Performance Neutral‐Color Semitransparent Organic Photovoltaics with Optical and Thermal Management

High‐Performance Neutral‐Color Semitransparent Organic Photovoltaics with Optical and Thermal Management

Optimal Semi-Transparent Photovoltaic (STPV) window based on energy performance, daylighting quality, and occupant satisfaction – A case study of private office in Chengdu China

With the global warming, energy crisis, and the increasing application of glazing curtain walls, semi-transparent photovoltaic (STPV) systems have garnered significant attention for their excellent energy performance and daylight quality. The cell coverage ratio (CCR) of an STPV window impacts energy performance, daylight quality, and occupants’ satisfaction simultaneously, though these impacts can be conflicting. Therefore, this study investigates the optimal CCR of STPV for optimal daylight, energy performance, and occupants' satisfaction in Chengdu City, China through a case study. A private office room was selected as the base model. Energy performance, and daylighting quality according to the different CCR (10% to 50%) of STPV were analyzed using Honeybee in Grasshopper (GH), which is a Plugin for Rhinoceros. Occupants’ satisfaction was assessed through a survey conducted with ClimateStudio (CS) and Virtual reality (VR). The results indicated that the optimal CCR of STPV for this room is as follows: East (30%), West (10%), North (10%), and South (40%), based on energy performance, daylight quality, and occupants’ satisfaction.

Simulation Study of Thermal Performance on the Inner and Outer Surfaces of Semi-Transparent Photovoltaic (STPV) Glass with Different Transparency

This paper used the experimentally verified one-dimensional steady-state heat transfer numerical model of the semi-transparent photovoltaic (STPV) glass to simulate the influence of wind speed, ambient temperature and air gap thickness on the surface temperature of PV modules, and analyzed the thermal performance of the inner and outer surfaces of STPV glazing with different transparency. Results shows that for every 1m/s increase in wind speed, the outer surface temperatures of SL-STPV glass with transparency of 10%, DL-STPV glass with transparency of 20% and 40% decreased by 3 °C, 3.02 °C and 2.22 °C, respectively. For every 10 °C increase in ambient temperature, the outer surface temperatures of SL-STPV glass with transparency of 10%, DL-STPV glass with transparency of 20% and 40% increase by 8.45 °C, 7.6 °C, and 7.79 °C, respectively. For the DL-STPV glass with transparency of 20% and 40%, for every 2 mm increase in the thickness of the air gap, the outer surface temperature increases by 0.13 °C and 0.12 °C, respectively. The heat transfer between the inner surface of the glass and the indoor environment increases the heat gain through the glass into the room in summer, which will lead to an increase in refrigeration energy consumption. However, in winter, the heat exchange between the inner surface and the in-door air to heat the indoor air reduces the heating energy consumption to a certain extent, and achieves the effect of building energy conservation to a certain extent.

The overall performance of a novel semi-transparent photovoltaic window with passive radiative cooling coating – A comparative study

Semi-transparent photovoltaic (STPV) glazing is a promising building integrated photovoltaic (BIPV) technology for converting traditional windows into on-site energy-producing building components. Besides electricity generation, there is also an urgent demand to enhance the thermal management of STPV glazing. Passive radioactive cooling paint is an emerging nanomaterials technology that shows great potential to reduce the painted surface temperature. Aiming to further promote the PV window’s energy efficiency, this study designed and investigated a novel coated semi-transparent photovoltaic (CSTPV) glazing supplemented with highly transparent passive radiative cooling coating. In addition, the STPV/CSTPV’s impacts on indoor visual environments were investigated, especially on the rarely studied aspect of interior colour rendering performance.This paper employs a combination of numerical simulation and experimental measurements to comprehensively assess these innovative glass systems in terms of electricity generation, thermal performance, daylighting efficiency, and the impact of color on the indoor environment. The results indicate that the CSTPV windows can significantly reduce the heat gain rate by about 15 % and achieve excellent electricity generation, with an annual output approximately 3 % higher than that of STPV windows. Despite the radiative cooling coating, CSTPV glazing maintains a level of daylight illumination comparable to that of STPV glazing, with glare levels remaining within acceptable limits. Furthermore, the study emphasizes the effects of CSTPV and STPV on the indoor Color Rendering Index (CRI) and Correlated Color Temperature (CCT) performance. All samples measured have CCT values within the range of neutral light, and CRI values exceeding 96, demonstrating satisfactory high-quality indoor lighting conditions. This research shows that CSTPV and STPV glass technologies not only significantly enhance the energy efficiency of buildings but also provide a scientific foundation for sustainable development in architectural design.

Semitransparent organic photovoltaics enabled by transparent p-type inorganic semiconductor and near-infrared acceptor

Semitransparent organic photovoltaics (STOPVs) have gained wide attention owing to their promising applications in building-integrated photovoltaics, agrivoltaics, and floating photovoltaics. Organic semiconductors with high charge carrier mobility usually have planar and conjugated structures, thereby showing strong absorption in visible region. In this work, a new concept of incorporating transparent inorganic semiconductors is proposed for high-performance STOPVs. Copper(I) thiocyanate (CuSCN) is a visible-transparent inorganic semiconductor with an ionization potential of 5.45 eV and high hole mobility. The transparency of CuSCN benefits high average visible transmittance (AVT) of STOPVs. The energy levels of CuSCN as donor match those of near-infrared small molecule acceptor BTP-eC9, and the formed heterojunction exhibits an ability of exciton dissociation. High mobility of CuSCN contributes to a more favorable charge transport channel and suppresses charge recombination. The control STOPVs based on PM6/BTP-eC9 exhibit an AVT of 19.0% with a power conversion efficiency (PCE) of 12.7%. Partial replacement of PM6 with CuSCN leads to a 63% increase in transmittance, resulting in a higher AVT of 30.9% and a comparable PCE of 10.8%.

Reliability of colorfast semitransparent organic photovoltaics

Reliability of colorfast semitransparent organic photovoltaics

Comprehensive performance investigation of a novel thermal catalytic semi-transparent PV double-skin ventilated window integrated with CdTe cells

Human health is adversely impacted by indoor formaldehyde. Given that buildings with conventional PV-DSVs fail to improve indoor air quality in the indoor or outdoor air circulation mode without any air handling devices. To remove indoor formaldehyde, a thermal-catalytic CdTe PV double-skin ventilated window is proposed. A corresponding mathematical model was established and validated against experiment data. Based on the validated model, the thermal, electrical, daylighting, and formaldehyde degradation performances were investigated and compared with a conventional PV-DSV (PV-CDSV). Additionally, parametric analysis was conducted to analyse impacts of four factors, including the area of catalytic coating, the window-to-wall ratio, outdoor solar radiation, and ambient temperature, on the energy performance of the proposed window. Main results are: (1) The proposed window had a higher power output but a bit lower thermal efficiency than PV-CDSV, and it had a higher ηtotal in winter, which reached 35.35 % and was 31.45 % higher than that of the PV-CDSV. (2) The net energy consumption of PV-TCDSV increased by 6.59 % and 6.26 % compared with PV-CDSV in winter and summer, respectively. (3) Among the four influencing factors, the solar radiation and ambient temperature had strong impacts on the effectiveness of formaldehyde degradation.

Experimental and simulation study on the thermoelectric performance of semi-transparent crystalline silicon photovoltaic curtain walls

This study aims to evaluate and optimize the thermoelectric performance of semi-transparent crystalline silicon photovoltaic (PV) curtain walls. An integrated thermoelectric performance coupling calculation model was developed, combining heat transfer and electricity generation calculations as a novel approach. Simulations and experiments were conducted to compare the performance of PV curtain walls with conventional curtain walls under various weather conditions, and were validated by experimental data. The results demonstrate that PV curtain walls enhance the thermal environment inside buildings and promote efficient power generation, with the arrangement of PV cells notably affecting performance. Under sunny conditions, the temperatures of the PV cell backplate and glass part backsheet in semi-transparent PV curtain walls exceeded those in ordinary glass curtain walls, yet the indoor air temperature was lower. Furthermore, when the working temperature of PV cells reaches to a certain level, it slightly deviates the electricity generation trend from the real-time solar radiation trend. Under cloudy conditions, the backsheet temperatures of semi-transparent PV curtain walls and standard glass curtain walls align with outdoor temperatures. Different PV module forms demonstrated that striped and square PV module forms offer better lighting effects than whole forms. The working temperatures among the three were close, with an annual average temperature difference of less than 1 °C and a peak temperature difference of approximately 3 °C, impacting the monthly total power generation by less than 1 %. This study presents a more precise and thorough approach for evaluating semi-transparent PV curtain walls' performance, providing insights for future sustainable architectural design.

Unveiling the Potential of Two-Terminal Perovskite/Organic Tandem Solar Cells: Mechanisms, Status, and Challenges.

Perovskite/organic tandem solar cells (PO-TSCs) demonstrate exceptional suitability for emerging applications such as building-integrated photovoltaics, wearable devices, and greenhouse farming. By leveraging the distinctive attributes of perovskite and organic materials, which encompass expanded solar spectrum utilization, chemically benign solubility, and soft nature, PO-TSCs position themselves as ideal candidates for high-performance semi-transparent photovoltaics (ST-PVs). Despite these advantages, their development significantly lags behind other perovskite-based counterparts, such as perovskite/perovskite, perovskite/silicon, and perovskite/Cu(In, Ga)Se2. To address existing challenges and unlock the full potential of PO-TSCs, an exploration of the fundamental mechanisms governing tandem photovoltaic devices is embarked. Delving into critical aspects such as charge generation/separation, energy level alignment, and material choices becomes pivotal for optimizing PO-TSC performance. The investigation of monolithic two-terminal PO-TSCs offers insights into achievements and barriers, recognizing the competitive landscape with other TSC counterparts. Further scrutiny of perovskite absorbers and organic absorbers in TSCs reveals strategies aimed at enhancing stability and efficiency. The discussion extends to interconnection layers, elucidating their role in optimizing light transmission and balancing carrier recombination. In conclusion, a compelling outlook on the dynamic landscape of PO-TSCs is presented, highlighting the remarkable efficiency progression and signaling their potential to revolutionize solar energy harvesting technologies.

Optical design and bandgap engineering in ultrathin multiple quantum well solar cell featuring photonic nanocavity

AbstractUltrathin solar cells are efficient and captivating devices with unique technological and scientific features in terms of minimal material consumption, fast fabrication processes, and good compatibility with semi‐transparent applications. Such photovoltaic (PV) technologies can enable effective synergy between optical and electronic confinements with large tuning capabilities of all the optoelectronic characteristics. In this work, the implications of the optical design and the bandgap engineering in ultrathin hydrogenated amorphous Si/Ge multiple quantum well (MQW) solar cells featuring photonic nanocavity are analyzed based on experimental measurements and optoelectronic modelling. By changing the period thicknesses and the positions of QWs inside the deep‐subwavelength nanophotonic resonator, the spatial and spectral distributions of the optical field and the local absorption are strongly affected. This leads to a modulation of the absorption resonance condition, the absorption edge and the resulting photocurrent outputs. Because of quantum confinement effect, the change of MQW configurations with different individual QW periods while keeping similar total thickness of about 20 nm alters both the bandgap energy and the band offset at the QW/barrier heterojunctions. This in turn controls the photovoltage as well as the carrier collection efficiency in solar cells. The highest open circuit voltage and fill factor values are achieved by employing MQW device configuration with 2.5 nm‐thin QWs. A record efficiency above 5.5% is reached for such emerging ultrathin Si/Ge MQW solar cell technology using thinner QWs with sufficient number, because of the optimum trade‐off between all the optoelectronic characteristic outputs. The presented design rules for opaque ultrathin solar cells with quantum‐confined nanostructures integrated in a photonic nanocavity can be generalized for the engineering of relevant multifunctional semitransparent PV devices.

Examining the effect of different photovoltaic modules on cucumber crops in a greenhouse agrivoltaic system: A case study

Agrivoltaic systems, a fusion of agriculture and photovoltaic (PV) technology, have emerged as a sustainable solution to optimise land use by enabling simultaneous solar energy and agricultural harvesting. The experiments were conducted in a polytunnel greenhouse in Kfar Qara, Israel, deploying three types of semi-transparent solar PV panels—bifacial glass-encapsulated silicon, bifacial plastic-encapsulated silicon, and semi-transparent organic photovoltaics (OPVs) installed above the plant canopy. The impact of these PV treatments on cucumber crops was evaluated and juxtaposed against a control greenhouse with no panels, over the spring season from February to June 2022. Key growth and yield metrics were recorded during 17 harvests between April 10 and June 2, 2022. The findings revealed a negligible decline in crop yield across PV panel treatments compared to the control. Notably, the control and glass-encapsulated silicon PV treatments demonstrated an increase in yield, growth, and fruit quality. Moreover, the glass-encapsulated silicon PV panels outperformed the plastic-encapsulated and OPV module power conversion in the high heat and humidity of the greenhouse environment. This study accentuates the potential of integrating glass-encapsulated silicon PV panels in polytunnel greenhouses, heralding a promising avenue for bolstering agrivoltaic applications by ensuring a harmonious balance between agricultural yield and electrical energy production.

Doping with KBr to Achieve High-Performance CsPbBr3 Semitransparent Perovskite Solar Cells.

Wide-bandgap semitransparent perovskite photovoltaics are emerging as one of the ideal candidates for building-integrated photovoltaics (BIPV). However, surface defects in inorganic CsPbBr3 perovskite prepared by vapor deposition severely limit the optoelectronic performance of perovskite solar cells. To address this issue, a strategy of doping a trace amount of KBr into perovskite by vapor deposition is adopted, effectively improving the quality of the film, reducing surface defect concentration, and enhancing the transportation and extraction of charge carriers. Simultaneously, fully physical vapor deposition technology is employed to fabricate perovskite solar cells with an average visible light transmittance of 44%. These devices exhibited an ultrahigh open-circuit voltage of 1.55 V and a superior power conversion efficiency (PCE) of 7.28%, demonstrating excellent moisture and heat resistance. Moreover, the corresponding 5 cm × 5 cm modules achieve a PCE of 5.35% with great thermal insulation capability. This work provides an approach for fabricating highly efficient all-inorganic perovskite solar cells with high average visible light transmittance, demonstrating new insights into their application in building-integrated photovoltaics.

Semi-Transparent PV and Double-Glazed Windows for Heat Reduction and Electricity Generation: A Study for Office Buildings in Tropical Climate

This research aims to develop a methodology for the evaluation of the potential energy saving and energy generation of semi-transparent PV and double-glazed window in Indonesia office buildings. The evaluation is based on Comsol software. The heat transfer equations for the inside the enclosure between the glass have been constructed according to the natural convection equation. The simulations were accomplished for four orientations from January until December and compared to a single-glazed window. The results show that it is possible to reduce the energy consumption for artificial lighting and air-conditioning using appropriate control systems and furthermore to generate electricity using semi-transparent photovoltaic panels in windows. The use of semi-transparent PV and double-glazed window has proven to be more effective in reducing heat transfer in buildings and generate electricity. East-facing double-glazed windows produce the most electricity, approximately 341 kWh.

Economic and Performance Analysis of Modified Solar Distillation System Coupling Different Integrations Using Carbon Quantum Dot Nanoparticles: Generalized Thermal Model

Abstract Clean drinking water and electricity production utilizing non-conventional sources of energy is the global demand for sustainable development. Ultrafast heat transfer fluids have delivered impressive results in photovoltaic (PV)-integrated solar thermal systems, in recent times. Efforts have been made for the productivity and electricity augmentation of solar still equipped with helically coilled heat exchanger and coupled with different integrations, viz., (a) partially covered N-photovoltaic thermal compound parabolic concentrator (N-PVT-CPC), (b) partially covered N-photovoltaic thermal flat plate collector (N-PVT-FPC), (c) N-FPC-CPC, and (d) N-flat plate collector (N-FPC). System design has also been modified by adding a roof-top semi-transparent PV module and built-in passive copper condenser (circulation mode), and effect of carbon quantum dots (CQDs) water-based nanofluids, nanoparticles volume concentration, and packing factor (βc) of the PV module has been studied by developing generalized thermal modeling of the system (special cases). Overall, 41.1%, 21.52%, 22.01%, and 10.01% rise in evaporative HTCs is observed in FPC-CPC, PVT-CPC, FPC, and PVT-FPC integrations, respectively. Thermal exergy is found to be higher for FPC-CPC integration, and it follows the enhancement order as FPC-CPC (max-0.147 kW) &amp;gt; PVT-CPC (0.088 kW) &amp;gt; FPC (0.038 kW) &amp;gt; PVT-FPC (0.028 kW). In reference to the base fluid, significant enhancement in the daily productivity is observed for FPC-CPC (10.9%) and PVT-CPC (5.16%) integrations using CQD-NPs. The production cost of potable water has also been estimated for all the cases for n = 30 and n = 50 years life span and i = 4% and 8% interest rates, and it is found to be the lowest (0.014 $/L) for FPC-CPC integration using CQD-NPs (n = 30 years, i = 4%).