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Jet impingement cooling enhances photovoltaic (PV) system efficiency by using high-speed fluid jets to reduce panel temperatures, improving performance and longevity. The effectiveness depends on factors like fluid flow rate, nozzle placement, and distance from the panel. While it boosts energy output, it may increase energy use for fluid circulation and add complexity to the system. This research explores a groundbreaking approach to enhancing the efficiency of bifacial photovoltaic thermal (BPVT) systems by integrating jet impingement technology. A novel design featuring a jet plate reflector is introduced, offering the dual benefit of cooling the PV panels while simultaneously reflecting light to optimize energy capture. The study comprehensively analyses the system’s performance, including energy output and a detailed techno-economic and environmental-economic evaluation. The modelling in this study was validated and reasonably consistent with experimental results. The system's output air temperature and thermal efficiency are 302.07–318.75 K and 33.83–62.28 %, respectively. The temperature and electrical efficiency range for PV systems are 304.39–339.54 K and 9.39–11.22 %. Reduced mass flow rate and increased solar irradiation are the most economically advantageous operating parameters for the proposed system, resulting in lower annual pumping costs and more significant annual energy gains for the system. CBR variations range from 0.1363 to 9.3445, with an average of 2. Additionally, by using BPVT with jet impingement to generate electricity rather than fossil fuels, it is possible to reduce annual carbon dioxide emissions by approximately 1.61 tons and save RM93.51 annually. In general, the proposed method should be used to minimize environmental pollution.

This work investigates the impact of combining light trapping and radiative cooling on bifacial solar panels. While several techniques have been proposed to enhance the efficiency of solar panels, their combination can lead to suboptimal results. By numerically evaluating the light absorption and thermal balance of different panel configurations, we found that each side of the bifacial solar cell can be textured independently with a cross-effect of less than 4%. However, our results also indicate that improving visible light trapping can increase infrared absorption, leading to a heating effect that may offset the benefits of radiative cooling. These findings highlight the importance of balancing the factors that influence solar panel efficiency and provide quantitative insights that guide the development of more effective solar energy systems.

This paper presents the investigations and performance analysis of monofacial and bifacial crystalline silicon solar cells with PC1D simulation software. The fundamental limitation in the monofacial solar cell's performance is its inability to absorb all the incoming solar radiation since the albedo effect (ground-reflected light that can be captured by the rear of the solar cell) is often neglected. So, the efficiency of the monofacial cell will be lower due to poor and incomplete optical absorption. Bifaciality helps to enhance the capturing of light in the solar cell, which means that the rear of the cell is exposed to solar radiation to produce electrical power. The primary focus of our work is to determine which solar cell offers better device performance and conversion efficiency by analyzing various parameters of the solar cell like surface texturing, emitter doping, bulk doping, minority carrier lifetime, bulk and surface recombination rates, front and rear reflectance, among other parameters. The other parameters are maintained at an optimal range to achieve the highest conversion efficiency. Our work has shown that the bifacial solar cell can be as efficient as 28.15%, which is much better than the 22.65% efficiency of the monofacial solar cell. [ABSTRACT FROM AUTHOR]

Solar concentrators are used in solar photovoltaic systems to lower the cost of producing electricity. In this situation, fewer solar cells can be used, lowering the overall cost of the system. The purpose of this article is to design, construct, install and test a stationary (non-tracking) concentrating system in Irbid, Jordan. Bifacial solar cells are used in the design. Two concentrator designs (with the same concentration ratio) are experimentally tested. Conc-A has a parabolic shape in the lower part but flat reflecting walls, whereas Conc-B has a standard compound parabolic shape in all parts. The receiving solar cells are arranged in three distinct positions in each concentrator. The results reveal that the output power from both concentrators is affected by the placement of the receiving solar cells within the concentrator. It has also been found that concentrators with flat reflecting walls perform better than those with parabolic reflecting walls. Conc-A's power collection is ~198% greater than that of a non-concentrating device. When Conc-B is used, the increase in power is ~181%. [ABSTRACT FROM AUTHOR]

In Cu2ZnSnS4 (CZTS) solar cells, it is crucial to suppress the generation of and remove the SnS2 secondary phase to improve the solar cell characteristics, as the SnS2 secondary phase affects the barrier for carrier collection and diode characteristics of the device. In this study, the nano-metallic precursor was modified to effectively suppress the generation of the SnS2 secondary phase on the surface and simultaneously improve the uniformity and quality of the thin film. The CZTS bifacial solar cells prepared via the proposed method exhibited significantly improved junction-rectifying characteristics, as the efficiency was improved to 1.59%. The proposed method to figurremove SnS2 is effective, simple, and environmentally friendly. [ABSTRACT FROM AUTHOR]

Nowadays all-dielectric nanophotonics is a powerful tool for improvement light management of thin-film optoelectronic devices because of low optical losses, strong light localization, and chemical robustness against such materials as halide perovskites. Here we propose a new highly efficient bifacial perovskite solar cells (PSCs) improved by introduction of light-trapping electrode (LTE), consisting of perforated Au + Spiro-OMeTAD layers covered with a densely array of SiO2 nanospheres. Our LTE combines charge collection and light trapping. We demonstrate that with our bifacial design of PSC with utilizing of LTE is more efficient over a monofacial analog by 3.5%. Our current study presents a new important step in research of photovoltaic facilities aimed to involve PSCs in real industrial development. [ABSTRACT FROM AUTHOR]

[Display omitted] • First investigation of ASnI 2 Br perovskite solar cells, achieving 21.94% PCE under rear-side illumination. • Explores three methods to estimate bifacial efficiency (η bi): characteristics addition (CA), generation addition (GA), and mathematical modeling (MM). • Validates methods using a baseline model calibrated with experimentally verified bifacial solar cells. • Maximum η bi reaches 28.75% (CA) and 30.17% (GA) under 100 mW cm-2 front- and 50 mW cm-2 rear-side illumination. • Optimum η bi of 31.05% achieved using tile as the rear surface material with GA. In this study, a novel perovskite bifacial solar cell featuring ASnI 2 Br as the absorber material, with the A-site cation represented by EDA 0.01 (GA 0.06 (FA 0.8 Cs 0.2) 0.94) 0.98 , was proposed. For the first time, the power conversion efficiency (PCE) of such a structure, achieving a notable 21.94% with rear-side illumination, was obtained. Additionally, the first investigation into three distinct methods for estimating the bifacial efficiency (η bi) of wide bandgap tin-perovskite bifacial solar cells, namely, characteristics addition (CA), generation addition (GA), and mathematical modeling (MM), was implemented. To validate the efficacy estimated by these methods, we apply them to an additional baseline model calibrated extensively with an experimentally verified bifacial perovskite solar cell (PSC) exposed to concurrent front- and rear illumination. Our findings indicate that the CA and GA methods outperform the MM, with the GA method closely aligning with experimental bifacial PSC parameters. Opting for the superior GA method, our analysis showed that the estimated η bi of the proposed device is 30.17% under 100 mW cm−2 front-side and 50 mW cm−2 rear-side illumination intensity. Furthermore, the η bi of the proposed device was evaluated under various experimentally calculated rear-side surface spectra, revealing an optimum η bi of 31.05% when the tile was used as the rear surface material. [ABSTRACT FROM AUTHOR]

An optimal tilt-angle control based on artificial intelligence (AI control) for tracking bifacial photovoltaic (BPV) systems is developed in this study, and its effectiveness and characteristics are examined by simulating a virtual system over five years. Using deep reinforcement learning (deep RL), the algorithm autonomously learns the control strategy in real time from when the system starts to operate. Even with limited deep RL input variables, such as global horizontal irradiance, time, tilt angle, and power, the proposed AI control successfully learns and achieves a 4.0–9.2% higher electrical-energy yield in high-albedo cases (0.5 and 0.8) as compared to traditional sun-tracking control; however, the energy yield of AI control is slightly lower in low-albedo cases (0.2). AI control also demonstrates a superior performance when there are seasonal changes in albedo. Moreover, AI control is robust against long-term system degradation by manipulating the database used for reward setting. [ABSTRACT FROM AUTHOR]

Reducing indium consumption, which is related to the transparent conductive oxide (TCO) use, is a key challenge for scaling up silicon heterojunction (SHJ) solar cell technology to terawatt level. In this work, we developed bifacial SHJ solar cells with reduced TCO thickness. We present three types of In2O3‐based TCOs, tin‐, fluorine‐, and tungsten‐doped In2O3 (ITO, IFO, and IWO), whose thickness has been optimally minimized. These are promising TCOs, respectively, from post‐transition metal doping, anionic doping, and transition metal doping and exhibit different opto‐electrical properties. We performed optical simulations and electrical investigations with varied TCO thicknesses. The results indicate that (i) reducing TCO thickness could yield larger current in both monofacial and bifacial SHJ devices; (ii) our IWO and IFO are favorable for n‐contact and p‐contact, respectively; and (iii) our ITO could serve well for both n‐contact and p‐contact. Interestingly, for the p‐contact, with the ITO thickness reducing from 75 nm to 25 nm, the average contact resistivity values show a decreasing trend from 390 mΩ cm2 to 114 mΩ cm2. With applying 25‐nm‐thick front IWO in n‐contact, and 25‐nm‐thick rear ITO use in p‐contact, we obtained front side efficiencies above 22% in bifacial SHJ solar cells. This represents a 67% TCO reduction with respect to a reference bifacial solar cell with 75‐nm‐thick TCO on both sides. [ABSTRACT FROM AUTHOR]

In Cu2ZnSnS4 (CZTS) solar cells, it is crucial to suppress the generation of and remove the SnS2 secondary phase to improve the solar cell characteristics, as the SnS2 secondary phase affects the barrier for carrier collection and diode characteristics of the device. In this study, the nano-metallic precursor was modified to effectively suppress the generation of the SnS2 secondary phase on the surface and simultaneously improve the uniformity and quality of the thin film. The CZTS bifacial solar cells prepared via the proposed method exhibited significantly improved junction-rectifying characteristics, as the efficiency was improved to 1.59%. The proposed method to figurremove SnS2 is effective, simple, and environmentally friendly.

This paper represents the theoretical and experimental performances of solar collector using an array of a single pass - air photovoltaic (PV) cells; replacing a diffuse reflector under a bifacial PV module (with an acceptable distance) instead of conventional absorber plate of photovoltaic-thermal (PVT) collectors. Energy and exergy analysis of the solar collector is done by mathematical modeling in one-dimensional steady state condition (1D-SS). A collector rack was designed and fabricated to examine and verify the theoretical model. The steady state exergy efficiency of 4.2 - 10% and energy efficiency 17 - 62% detected for both 0.04 - 0.13 kg/s and 0.22, 0.33, 0.50 and 0.67 of airflow rate and packing factor respectively. The prevailing output of the collector is thermal energy while electricity is the dominant output of exergy. In the range of 0.04 - 0.13 kg/s, airflow rate has no influence on the overall exergy of the collectors due to the strong dependency of the total exergy on electrical output rather than thermal one. Finally, as the result of increasing airflow rate, the overall output energy of the collector increases due to the increase of the thermal energy harvest.

A new crystalline-Si (c-Si) solar cell design based on bifacial heterojunction back contact (HBC) with a transparent conductive oxide (TCO) is proposed by the numerical simulation method. Three bifacial HBC schemes are evaluated and compared: full-area contact with an increase in the pitch distance, point contact, and point contact with indium tin oxide (ITO). The results reveal that point contact with ITO is the most optimal among the three aforenoted schemes. The bottleneck of bifacial HBC is caused by the extremely low carrier mobility in an amorphous Si (a-Si) region, and this can be resolved by applying ITO to form a full-contact area that covers all surfaces of the a-Si region. A maximum power density of 29 mW/cm2 is obtained from bifacial HBC, which is an extremely high output from a single-junction c-Si solar cell. The improvement in the maximum power density over the monofacial condition is 8% at 20% albedo. [ABSTRACT FROM AUTHOR]

An optimal tilt-angle control based on artificial intelligence (AI control) for tracking bifacial photovoltaic (BPV) systems is developed in this study, and its effectiveness and characteristics are examined by simulating a virtual system over five years. Using deep reinforcement learning (deep RL), the algorithm autonomously learns the control strategy in real time from when the system starts to operate. Even with limited deep RL input variables, such as global horizontal irradiance, time, tilt angle, and power, the proposed AI control successfully learns and achieves a 4.0–9.2% higher electrical-energy yield in high-albedo cases (0.5 and 0.8) as compared to traditional sun-tracking control; however, the energy yield of AI control is slightly lower in low-albedo cases (0.2). AI control also demonstrates a superior performance when there are seasonal changes in albedo. Moreover, AI control is robust against long-term system degradation by manipulating the database used for reward setting.

Bifacial a‐SiOx:H/a‐SiOx:H/a‐Si:H/a‐SiOx:H/a‐SiOx:H quintuple‐junction and a‐SiOx:H/a‐SiOx:H/a‐Si:H/a‐Si:H/a‐SiOx:H/a‐SiOx:H sextuple‐junction solar cells were prepared by the PE‐CVD. The solar cell has a structure in which both sides are sandwiched between ITO layers, and the structure allows light irradiation from both sides. A total of 49 cells having an area of 0.25 cm2, 0.5 cm2, and 1 cm2 was fabricated on a 10 cm × 10 cm substrate. The distribution of open‐circuit voltage, Voc, under low illumination in all 49 solar cells was investigated. As one example of applying bifacial multi‐junction a‐Si based solar cells as an independent power source for the Internet of Things (IoT) devices, a flexible bifacial quintuple‐junction solar cell was also prepared. In the sextuple‐junction solar cell, an open‐circuit voltage of 4.1 and 3.5 V was obtained even at a low illuminance of 3000 and 100 lux, respectively. In the quintuple‐junction solar cell formed on the polyimide film substrate, an open‐circuit voltage of 3.2 and 2.7 V was obtained at 3000 and 100 lux, respectively. The decreasing amount of the open circuit voltage when the irradiation intensity became 1/10, ΔVoc (1/10), was 62–64 mV/cell. [ABSTRACT FROM AUTHOR]

• Device design is theoretically performed for bifacial Cu(In,Ga)Se 2 solar cells. • Bandgap grading in Cu(In,Ga)Se 2 layer improves performance under rear illumination. • Rear surface layer with widegap reduces carrier recombination at the back contact. • Increment of optical path length by forming the surface texture is useful. • These findings indicate a guideline for the high-performance bifacial solar cells. For bifacial solar cells, a gain of 10–50% of the electric power generation by harvesting albedo radiation is expected compared with mono-facial solar cells. Cu(In,Ga)Se 2 (CIGSe) is a promising photovoltaic material owing to its unique physical properties, whereas the knowledge of the bifacial CIGSe solar cells is not fully understood. In this article, high efficiencies under front and rear illuminations for the bifacial CIGSe solar cells are theoretically demonstrated. An adequate bandgap grading by Ga/(Ga + In) ratio in the CIGSe layer leads to a shift of the depth in carrier-generation toward pn -junction and driving force of electron transport by electric field, resulting in improvement of device performance. On the other hand, it is also disclosed that the effect of bandgap grading alone is not enough to obtain the high short-circuit current density (J SC) under rear illumination. It is found that improvement of a CIGSe quality and an introduction of a rear surface layer contribute to reduction of the carrier recombination at the bulk and back contact, respectively, leading to enhanced J SC in rear illumination. Furthermore, the effect of optical path length by the surface texture is discussed. These findings indicate a guideline for the promising high-performance bifacial CIGSe solar cells. [ABSTRACT FROM AUTHOR]

This study presents the impact of surface modification on bifacial solar cells through single-pulse drilling to enhance efficiency and optical characterisation. A single-pulse laser operates at a wavelength of 1.06 μm, and the microsecond length is a function of its energy and structure setup. The front surface is drilled with two laser energy settings, namely, 23.5 W and 39.6 W, to create a range of micro-holes with distinct depths, widths and crystallographic defects. The modification of the front laser surface has enhanced current density and effectiveness by capturing light in the crystallisation region and the inner region of the micro-holes. Cell topography shift reduces the recombination of electron/hole on the surface. The rear surface registers efficiency digression because of a crystallographic defect that increases optical losses that boost the recombination of hole/electron. The efficiency of the cell with low-power front surface laser drilling increases 1.38%, but that of the cell with low-power back surface laser drilling drops 2.12%. High-power laser drilling increases 1.46% for the front surface and decreases 1.36% for the back surface. Optical characterisation via infrared transmission shows that light increment at a wavelength of 1100 nm is transmitted through the laser drill's micro-holes. The different depths and widths of the micro-holes determine the light transmission rate that can travel to the back surface. The growth of holes improves the light-scattering and absorption regions, affecting cell efficiency. [ABSTRACT FROM AUTHOR]

Colloidal PbS quantum-dot solar cells (QDSCs) have long suffered from inefficient charge collection near the back-junction due to the lack of p-doping strategy, rendering their bifacial photovoltaic applications unsuccessful. Here, we report highly efficient photocarrier collection in bifacial colloidal PbS QDSCs by exploiting spray-coated silver nanowires (AgNWs) top electrodes. During our spray-coating process, pressurized Ag diffusion occurred toward the active layer, which induced effective p-doping and deep-level passivation. By manipulating the spray pressure, optimum AgNWs' stacking morphology enabling an appropriate level of Ag diffusion could be achieved, leading to J sc over 30 mA/cm 2 from the conventional n-i-p structure upon light illumination to the film side. The morphological and electrical behaviors of AgNWs according to the spray pressure are comprehensively explained in relation to the device performance. Finally, 50 bifacial cells were fabricated over 49 cm 2 sized glass substrate, demonstrating the large-area processability and functionality of the spray-coated AgNWs with the effective back-junction engineering.

Abstract: Hydrogen‐doped In2O3 (IOH) films are used as a transparent back contact in bifacial Cu(In,Ga)Se2 (CIGS) solar cells. The effect of the IOH thickness and the impact of the sodium incorporation technique on the photovoltaic parameters are studied, and clear correlations are observed. It is shown that a loss in short circuit current density (JSC) is the major limitation at back side illumination. The introduction of a thin Al2O3 layer on top of the IOH significantly increases the collection efficiency (ϕ(x)) for electrons generated close to the back contact. In this way, the JSC loss can be mitigated to only ~ 25% as compared with front side illumination. The Al2O3 film potentially reduces the interface defect density or, alternatively, creates a field effect passivation. In addition, it prevents the excessive formation of Ga2O3 at the CIGS/IOH interface, which is found otherwise when a NaF layer is added before absorber deposition. Consequently, detrimental redistributions in Ga and In close to the back contact can be avoided. Finally, a bifacial CIGS solar cell with an efficiency (η) of η = 11.0% at front and η = 6.0% at back side illumination could be processed. The large potential for further improvements is discussed. [ABSTRACT FROM AUTHOR]

Abstract: This study evaluates the potential of hydrogen‐doped In2O3 (IOH) as a transparent back contact material in (Agy,Cu1‐y)(In1‐x,Gax)Se2 solar cells. It is found that the presence of Na promotes the creation of Ga2O3 at the back contact during (Agy,Cu1‐y)(In1‐x,Gax)Se2 growth. An excessive Ga2O3 formation results in a Ga depletion, which extends deep into the absorber layer. Consequently, the beneficial back surface field is removed and a detrimental reversed electrical field establishes. However, for more moderate Ga2O3 amounts (obtained with reduced Na supply), the back surface field can be preserved. Characterization of corresponding solar cells suggests the presence of an ohmic back contact, even at absorber deposition temperatures of 550°C. The best solar cell with an IOH back contact shows a fill factor of 74% and an efficiency (η) of 16.1% (without antireflection coating). The results indicate that Ga2O3 does not necessarily act as a transport barrier in the investigated system. Observed losses in open circuit voltage (VOC) as compared to reference samples with a Mo back contact are ascribed to a lower Na concentration in the absorber layer. [ABSTRACT FROM AUTHOR]

Bifacial solar cells that maximize the energy output per a square meter have become a new fashion in the field of photovoltaic cells. However, the application of thin-film material on bifacial solar cells, viz., thin-film amorphous hydrogenated silicon ( a- Si:H), is extremely rare. Therefore, this paper presents the optimization and influence of the band gap, thickness and doping on the performance of a glass/glass thin-film a- Si:H ( n- i- p) bifacial solar cell, using a computer-aided simulation tool, Automat for simulation of hetero-structures (AFORS-HET). It is worth mentioning that the thickness and the band gap of the i-layer are the key parameters in achieving higher efficiency and hence it has to be handled carefully during the fabrication process. Furthermore, an efficient thin-film a- Si:H bifacial solar cell requires thinner and heavily doped n and p emitter layers. On the other hand, the band gap of the p-layer showed a dramatic reduction of the efficiency at 2.3 eV. Moreover, a high bifaciality factor of more than 92% is attained, and top efficiency of 10.9% is revealed under p side illumination. These optimizations demonstrate significant enhancements of the recent experimental work on thin-film a- Si:H bifacial solar cells and would also be useful for future experimental investigations on an efficient a- Si:H thin-film bifacial solar cell. [ABSTRACT FROM AUTHOR]

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There have been sustained interest in bifacial solar cell technology since 1980s, with prospects of 30–50% increase in the output power from a stand-alone panel. Moreover, a vertical bifacial panel reduces dust accumulation and provides two output peaks during the day, with the second peak aligned to the peak electricity demand. Recent commercialization and anticipated growth of bifacial panel market have encouraged a closer scrutiny of the integrated power-output and economic viability of bifacial solar farms, where mutual shading will erode some of the anticipated energy gain associated with an isolated, single panel. Towards that goal, in this paper we focus on geography-specific optimization of ground-mounted vertical bifacial solar farms for the entire world. For local irradiance, we combine the measured meteorological data with the clear-sky model. In addition, we consider the effects of direct, diffuse, and albedo light. We assume the panel is configured into sub-strings with bypass-diodes. Based on calculated light collection and panel output, we analyze the optimum farm design for maximum yearly output at any given location in the world. Our results predict that, regardless of the geographical location, a vertical bifacial farm will yield 10–20% more energy than a traditional monofacial farm for a practical row-spacing of 2 m (corresponding to 1.2 m high panels). With the prospect of additional 5–20% energy gain from reduced soiling and tilt optimization, bifacial solar farm do offer a viable technology option for large-scale solar energy generation. [ABSTRACT FROM AUTHOR]

In traditional dye-sensitized solar cells (DSSCs), the liquid electrolyte (LE) presents a problem for long-term stability. Herein, we demonstrate a bifacial DSSC by combining a new metal-free organic dye and a quasi-solid state electrolyte (QSSE) that contains poly(vinylidenefluoride- co -hexafluoropropylene) (PVdF-HFP)-based polymer gel. The incident light irradiates the front side of the DSSC, and the transmitted light is reused after reflection on the back side. Owing to the semi-transparent DSSC electrode, the reflected light can penetrate and be absorbed by the dye molecules in the DSSC, thereby enhancing the short-circuit current density and thus the overall power conversion efficiency (PCE). The PCE for the DSSC device with QSSE from bifacial irradiation is 10.37%, a value that is comparable to that obtained with LE-based DSSC (9.89%). The stability of the device is enhanced when the polymer gel containing PVdF-HFP is mixed with the LE, and the effectiveness of PVdF-HFP as a gelator is attributed to its interaction with the Li + ions. Based on our preliminary results, this architecture can lead to more stable bifacial QSSE-based DSSCs without sacrificing the photovoltaic performance. [ABSTRACT FROM AUTHOR]

This paper presents the experimental and analytical investigation of four air-based bifacial photovoltaic thermal collectors. The experiments were performed on four bifacial PV panels with four different packing factors and four different configurations of air-based PVT collectors. A mathematical model was developed to evaluate the energy and exergy performance of the collectors. The four designs were studied in under the steady-state conditions. All four models of photovoltaic thermal collectors were fabricated and indoor experimental studies were conducted using the solar simulator. The double-path parallel flow design indicated the highest total energy efficiency of 51%–67%, and the single-path design indicated the lowest total energy efficiency of 28%–49%, at a 0.7 packing factor. The single-path collector design is the best option if electrical energy is the dominant desired output energy. However, double-path parallel flow design is the best option if the thermal energy is the dominant desired output energy. In addition, the single-path design had the highest exergy efficiency (8.2%–8.4%) followed by double-path parallel flow design (7.2%–8%). [ABSTRACT FROM AUTHOR]

We present an optical design for a static solar concentrator for a photovoltaic cell (SCPV). The concentrator consists of two Fresnel lenses, one concave and one convex. The SCPV was designed and optimized using ray-tracing computer simulations. The performance of the SCPV was demonstrated using two settings: static mode and periodic mode with passive bi-yearly angle adjustments. Even without an active tracking system, the SCPV achieved an average Concentration ratio (CR) in the range of 1.94-2.86. The CR was distributed non-uniformly throughout the year, and the value and season of the highest CR were different for the two settings. The optimal mode for SCPV use can be chosen by balancing specific preferences regarding the target season for peak performance, maximum average CR, and maintenance frequency. [ABSTRACT FROM AUTHOR]

Simple diffuse rear reflectors can enhance the light path length of weakly absorbed near infrared light in silicon solar cells and set a benchmark for more complex and expensive light trapping structures like dielectric gratings or plasmonic particles. We analyzed such simple diffuse rear reflectors systematically by optical and electrical measurements. We applied white paint, TiO 2 nanoparticles, white backsheets and a silver mirror to bifacial silicon solar cells and measured the enhancement of the external quantum efficiency for three different solar cell geometries: planar front and rear side, textured front and planar rear side, and textured front and rear side. We showed that an air-gap between the solar cell and the reflector decreases the absorption enhancement significantly, thus white paint and TiO 2 nanoparticles directly applied to the rear cell surface lead to the highest short circuit current density enhancements. The short circuit current density gains for a 200 µm thick planar solar cell reached up to 1.8 mA/cm 2 , compared to a non-reflecting black rear side and up to 0.8 mA/cm 2 compared to a high-quality silver mirror rear side. For solar cells with textured front side the short circuit current density gains are in the range between 0.5 and 1.0 mA/cm 2 compared to a non-reflecting black rear side and do not significantly depend on the angular characteristic of the rear side reflector but mainly on its absolute reflectance. [ABSTRACT FROM AUTHOR]

The effects of impinging air jet on the thermo-electro-hydraulic performance of a bifacial PVT with different packing factors are entirely unclear. Here, we have proposed a dual-functional jet plate reflectors are introduced to induce jet air cooling and increase the light absorption at the rear part of the bifacial PV module. The effects of jet plate reflectors with different configurations on the system's performance are investigated and studied. The simulation results were verified and validated with the experimental findings. Increasing the distance between jet holes reduces the interference and enhances the heat transfer, which led to higher friction and greater pumping power. Net energy gain is the key to calculate hydraulic efficiency, by subtracting the pumping power from the energy output. Therefore, the system's best performance can be explained by the lowest Re to generate max efficiencies. Jet impingement bifacial photovoltaic thermal (JIBPVT) with 36 jet-holes has the greatest jet spacing between the jet holes and optimum performance. The maximum thermal energy gain and electrical energy produced were achieved at lower critical values of Re, which are 9929 and 5667, respectively. JIBPVT has the optimum thermal, electro, and thermo-electro-hydraulic efficiencies, with 57.3%, 10.36%, and 83.93%, respectively. • A novel design of jet impingement bifacial photovoltaic thermal (JIBPVT) solar air collector was presented. • Dual-fuctional jet plate reflectors with different geometric configurations were introduced. • A one-dimensional heat flow analytical model in steady-state was developed for JIBPVT solar air collector. • The simulation results were validated with experimental results and a good agreement was shown between them. • Thermo-electro-hydraulic analysis, which taken friction factor, pressure drop, and pumping power were discussed. [ABSTRACT FROM AUTHOR]

The dynamic impedance Z (ω,θ) of bifacial Silicon solar cell under incidence angle, obtained by the ratio of the photocurrent density JPh(ω,θ) to the photovoltage VPh (ω,θ), is studied by use of Nyquist and Bode diagrams in order to determine electrical parameters. [ABSTRACT FROM AUTHOR]

In this paper we report on the fabrication of laser-doped p-type bifacial cells using self-aligned metal-plating with energy conversion efficiencies as high as 19.2%. A key fabrication step for these cells is recognising that the p-type silicon regions can be made cathodic by forward biasing the p–n junction in a process which we call here field-induced plating (FIP). Used in conjunction with light-induced plating (LIP) in the same plating apparatus, FIP can be used to form low cost nickel/copper grids on both surfaces of a cell. Furthermore, the simplicity of the FIP process means that it can potentially be performed using the same plating equipment and chemistry as used for LIP. Plating rates similar to LIP were achieved (i.e., ~10 µm of copper in 10 min), however there is potential to plate at much faster rates with FIP because the junction is forward-biased. This bifacial cell plating method could be adapted to metallise a range of bifacial cells including heterojunction cells. [ABSTRACT FROM AUTHOR]

ABSTRACT We present a new method to characterize bifacial solar cells under standard test conditions (STC). The method considers the bifacial operation of the cell and provides the characteristics for simultaneous front and rear side illumination rather than providing the front and the rear side characteristics separately. The method involves measurements of front side electrical parameters (efficiency, open-circuit voltage, short-circuit current and fill factor) and rear side short-circuit current under STC. Two new parameters are introduced, namely bifacial 1. x efficiency (effective efficiency) and gain-efficiency product, which are calculated from the measured STC parameters. The former provides information related to the cell design considering the bifacial operation, whereas the latter provides the end-use benefits from the modules with bifacial cells for a particular installation. To calculate the bifacial 1. x efficiency and the gain-efficiency product, a one-diode solar cell equivalent circuit is used. Characteristic plots are shown for the newly introduced parameters as a function of rear-side illumination for various example solar cells. A sensitivity analysis is performed to understand the influence of each single-sided STC solar cell parameter on the newly introduced parameters. This sensitivity analysis shows that the fill factor and the rear-to-front current ratio are the most critical parameters for bifacial solar cells. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Up to date most spin-on diffusion sources based on wet chemical created boron-silicate glass (BSG) lead to a strongly degraded carrier lifetime after diffusion. In this study the implication of a spin-on boron diffusion source is applied to the fabrication of large area n-type CZ bifacial solar cell and the performance of the spin-on source is compared to a BBr3 boron diffusion concerning the resulting lifetime and emitter saturation current J0e. Comparable J0e values and a comparable lifetime have been achieved resulting in a top efficiency of 19.38% in comparison to a top efficiency of 19.60% achieved by BBr3 diffusion. [Copyright &y& Elsevier]

This paper examines the steady-state and transient performance of a single-path air-based bifacial photovoltaic thermal (PVT) panel with regard to the first and second laws of thermodynamics. A bifacial PVT panel requires an appropriate reflector behind the solar cells, rather than an absorber plate. A flat plate air-based PVT panel was developed based on the bifacial PV cells requirement. A mathematical model was developed to evaluate the energy and exergy performance of the panel. 8.5% exergy efficiency observed for packing factor 0.7 while the energy efficiency increase from 39% to 55% by increasing the flow rate from 0.038 kg/hr to 0.14kg/hr. The maximum energy output 270W/m² observed at a typical day based on the climate of Malaysia, while the exergy out put reached to 50 W/m². [ABSTRACT FROM AUTHOR]

Abstract: An alternative process to the aluminium full back side is necessary to realize high efficiency solar cell on thin wafers. Even if metallization paste manufacturers deliver paste that minimize the wafer bowing to 1.5mm for wafer lower than 200μm, it is more and more critical to process wafers thinner than 150μm with full aluminium back side. The objective of this work is to demonstrate on monocristalline silicon wafer that boron back surface field (BSF), diffused from BCl3 gas source or from oxide doped layer like Boron Silicon Glass (BSG), is as efficient as full back side aluminium BSF. In addition this work deal with integration of different passivation layer optimised to passivate high boron doped layer at the backside of a bifacial solar cell. The best efficiency obtained on monocristalline wafers shows an increase in efficiency of 0.9% absolute compare to our standard process with full aluminium back side. According to the process optimised for monocristalline wafers, the process was transferred on multicristalline wafer. Even if the gain in current, for bifacial solar cell, compared to standard process is confirmed, the high temperature process for boron diffusion, activate electrically lot of intra-grain defects and decrease the solar cell performance. A correlation between Light Beam Induced Current (LBIC) and electroluminescence highlight local shunt and explain why the solar cell performance with boron BSF diffused at the back side is impacted. An alternative solution is also proposed to reduce the thermal budget of boron diffusion and improve the solar cell efficiency. [Copyright &y& Elsevier]

Abstract: To lower the fabrication cost of silicon solar cells, a surface treatment using a dielectric barrier discharge (DBD) instead of a wet cleaning technique was examined on electrode surfaces on silicon solar cells. The fill factor obtained through measuring current–voltage characteristics was evaluated, and the treated surface state was characterized by energy-dispersive X-ray. It was found that the DBD effectively activated the electrode surface and the surface treatment on finger electrodes contributed greatly to improve the fill factor. [Copyright &y& Elsevier]

In order to realize a photovoltaic (PV) solar power system which is low cost and flexible on its installation, the authors have studied vertical installations of bifacial solar modules. Simulation studies and field tests were performed in order to evaluate daily and yearly output energies when bifacial modules are vertically installed at various azimuth angles. It is clarified that the yearly generated energies by a vertically installed bifacial module are equivalent to those of a monofacial module facing south with an optimum tilt, regardless of the azimuth angles. According to the above results, some applications have been successfully demonstrated including a fence-integrated PV system and a pole-mounted PV system. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(3): 32–42, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10370 [ABSTRACT FROM AUTHOR]

• Ti-doped indium oxide layer was used in bifacial Cu(In 1-x ,Ga x)Se 2 (CIGS) solar cell. • Quantum efficiency for rear-side illumination improved by CsF treatment. • Effect of heat-light soaking investigated in CsF-treated bifacial CIGS solar cell. Bifacial Cu(In 1-x ,Ga x)Se 2 (CIGS) thin film solar cells were fabricated on titanium-doped indium oxide (ITiO) coated soda-lime glass substrate, and the effect of cesium fluoride (CsF) treatment on solar cell performance was investigated. CsF treatment improved the photovoltaic properties of CIGS/ITiO-based solar cells not only under front-side illumination but also under rear-side illumination. The quantum efficiency for rear-side illumination improved significantly in CsF-treated CIGS solar cells. As a result, the bifaciality improved in the CsF-treated CIGS solar cell. ITiO exhibited good contact with the CIGS thin film, regardless of Cs incorporation. In addition, the effect of heat-light soaking treatment was also investigated in CIGS/ITiO-based solar cells. [ABSTRACT FROM AUTHOR]