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Bulk luminescent solar concentrators based on organic-inorganic CH3NH3PbBr3 perovskite fluorophores
摘要： In this paper, we report characterization and performance results of lead bromide perovskite luminescent solar concentrator. CH3NH3PbBr3 fluorophores are synthesized by sonication method and examined by their X-ray diffraction pattern and scanning electron microscopy. Synthesized perovskite shows excitonic absorption at 524 nm and PL emission peak located at 532 nm with a Stokes shift around 8 nm. Micron-sized fluorophores are dissolved in prepared solutions and uniformly embedded in PMMA host with 0.006–0.120%wt concentration. Then, Fabricated devices are cut into 50 × 30 × 5 mm cuboid shapes and placed in a mirror surrounded configuration with an attached photovoltaic cell. Fabricated device is put under standard AM1.5 illumination and the output spectrum from the concentrator is acquired. Re-absorption in the samples is also measured by variable optical path method, showing red-shifts up to 13 nm in the output spectrum. Spatially resolved photo-luminescence maps and optical efficiencies are also presented for each sample. Plus, a Monte-Carlo ray tracing algorithm is developed to assist better understanding the experimental results. Stability of fabricated samples are evaluated under high intensity UV illumination, reporting efficiency reduction around 15% after 24 h. Finally, Comparing current-voltage characterization of the attached photovoltaic cell reveals optimized efficiency enhancement in the 0.04%wt sample above 65%.
关键词： Perovskites,Monte-Carlo simulation,Re-absorption,Luminescent solar concentrators,Photovoltaic conversion efficiency,Solar cells
更新于2025-11-14 15:30:11
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Improving Interfacial Charge-Transfer Transitions in Nb-Doped TiO2 Electrodes with 7,7,8,8-Tetracyanoquinodimethane
摘要： Interfacial charge-transfer (ICT) transitions involved in charge-separation mechanisms are expected to enable efficient photovoltaic conversions through one-step charge-separation processes. With this in mind, the charge-transfer complex fabricated from TiO2 nanoparticles and 7,7,8,8-tetracyanoquinodimethane (TCNQ) has been applied to dye-sensitized solar cells. However, rapid carrier recombination from the conduction band of TiO2 to the highest occupied molecular orbital (HOMO) of TCNQ remains a major issue for this complex. In this study, to inhibit surface-complex recombinations, we prepared Nb-doped TiO2 nanoparticles with different atomic ratios for enhanced electron transport. To investigate the effects of doping on electron injection through ICT transitions, these materials were examined as photoelectrodes. When TiO2 was doped with 1.5 mol % Nb, the Fermi level of the TiO2 electrode shifted toward the conduction band minimum, which improved electron back-contact toward the HOMO of TCNQ. The enhancement in electron transport led to increases in both short circuit current and open circuit voltage, resulting in a slight (1.1% to 1.3%) improvement in photovoltaic conversion efficiency compared to undoped TiO2. Such control of electron transport within the photoelectrode is attributed to improvements in electron injection through ICT transitions.
关键词： photovoltaic conversion,Nb-doped TiO2,interfacial charge-transfer transition,7,7,8,8-tetracyanoquinodimethane
更新于2025-09-23 15:21:01
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Optical functional film with triangular pyramidal texture for Crystalline silicon solar cells
摘要： An optical functional film with triangular pyramidal texture is proposed to reduce the reflection loss of crystalline silicon cells in order to solve the problem where directly fabricating the light-trapping texture on the surface of crystalline silicon can increase of surface photogenerated carrier recombination in crystalline silicon cells. The models of the reflection and refraction loss of light on the surface of an optical functional film with triangular pyramidal texture are developed. Afterwards, the triangular pyramidal textured film is bonded to the smooth surface of crystalline silicon cells and the angle between the base and side of the triangular pyramid is optimized. According to the large-area fabricating process of the optical functional film with triangular pyramidal texture, the proper structural parameters of the textured film are obtained. The optical functional film with triangular pyramidal texture was fabricated by means of ultra-precision cutting, electroforming, and embossing processes. Moreover, the effect of the fabricating precision on the optical performance of the triangular pyramid textured film is analyzed. The experimental and analytical results indicate that, by using the triangular pyramid textured film, the reflection loss of the smooth surface crystalline silicon cells decreases from 22.3% to 7.2% and the photovoltaic conversion efficiency increases from 18.30% to 20.47%. Compared with conventional textured crystalline silicon cells, the photovoltaic conversion efficiency of smooth surface crystalline silicon cells with the proposed optical functional film increases by 0.99%. An optical functional film with a triangular pyramidal texture can effectively improve the absorbance and photovoltaic conversion efficiency of smooth surface crystalline silicon cells.
关键词： Triangular pyramid,Optical properties,Crystalline silicon cells,Photovoltaic conversion efficiency,Optical functional textured film
更新于2025-09-23 15:19:57
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N multiple quantum dot solar cells
摘要： In this work, we investigate the influence of the internal electric field induced by the polarization inside the active region of the p-i-n photodiode on the characteristics of InN/InGaN quantum dots intermediate band solar cell. Considering the conduction and valence band offsets, the electron and hole energy levels have been determined by solving analytically the corresponding Schr?dinger equations. The hole level, usually neglected in similar studies, is taken into account to determine all the intermediate transitions. All parameters of multiple quantum dot solar cells such as open-circuit voltage, short-circuit current density and photovoltaic conversion efficiency are determined as functions of the indium content, the internal electric field, inter-dot distances and dot sizes. Our calculations show that determining the photovoltaic conversion efficiency (η) without taking into account the internal electric field leads to an overestimation of η.
关键词： Temperature effect,Intermediate level,Internal electric field,Solar cell,Photovoltaic conversion efficiency
更新于2025-09-23 15:19:57
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Composite electrode of TiO2 particles with three kinds of crystal phases for significantly improved performance of dye-sensitized solar cells
摘要： A novel composite electrode of TiO2 particles with three kinds of crystal phases is fabricated for improving the dye-sensitized solar cell's performance. The photoelectric conversion efficiency of solar cell with the content of 30 wt% brookite nanocubes and 70 wt% P25 could reach 7.40%. It is obvious that brookite nanocubes are advantageous in terms of reduced charge recombination and higher voltage. On the other hand, P25 gives advantages of high surface area for dye loading and higher charge collection efficiency. This work shows a new photoelectrode design for enhanced energy conversion of DSSCs.
关键词： Composite electrode,Dye-sensitized solar cell,Brookite titania,Photoelectrochemcial property,Photovoltaic conversion efficiency
更新于2025-09-23 15:19:57
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Photovoltaic performance of one axis multiple-position sun-tracked PV panels
摘要： In this article, the photovoltaic performance of one-axis multiple-positions sun-tracked photovoltaic panels (MP-PV) is investigated based on solar geometry and dependence of photovoltaic conversion efficiency on the incident angle (IA) of solar rays on PV panels. For such PV system, the azimuth angle (AZA) of PV panels is daily adjusted several times (M) from eastward in the morning to westward in the afternoon by rotating PV panels about inclined north-south axis (INSA) to ensure the projected incident angle (PIA) of solar rays on the plane perpendicular to INSA is always less than the specified angle θa. Results show that, the annual electricity generation (AEG) of MP-PV increases with the increase of M, but such increase is not noticeable when M>5. For MP-PV with the tilt-angle (β) of INSA being yearly fixed (1T-MP-PV), the optimal θa of 3P-,5P- and 7P-PV for maximizing AEG are respectively 24o, 15o and 11.5o, and their AEGs are respectively about 92%, 94% and 95% of that from similar 2-axis tracked PV panels (2A-PV). Whereas for MP-PV with the β being yearly adjusted four times at three tilts (3T-MP-PV), the optimal θa of 3P-, 5P- and 7P-PV are respectively about 22.5o, 14.5o and 11o, and the Pa are respectively about 96%, 98% and 99% of that of similar 2A-PV systems.
关键词： photovoltaic conversion efficiency,azimuth angle,annual electricity generation,solar geometry,sun-tracked PV panels,incident angle,photovoltaic performance
更新于2025-09-16 10:30:52
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Dye-sensitized solar cells using fluorone-based ionic liquids with improved cell efficiency
摘要： Dye-sensitized solar cells using fluorone-based ionic liquids with improved cell efficiency. Six trihexyltetradecylphosphonium chloride (P6,6,6,14Cl) based ionic liquids (IL) with dianionic fluorone derivatives were synthesized with total exchange of chloride from the dianionic dye: Fluorescein (a), Rose Bengal (b), Phloxine B (c), Eosin B (d), Eosin Y (e) and Erythrosin B (f). Spectroscopic characterization of these viscous salts indicated the presence of the expected 1 or 2 strong absorption bands. A total of 12 compounds, as sodium (from a to f) or as trihexyltetradecylphosphonium dianion salts (from a0 to f0), were used for sensitization of nanocrystalline TiO2. Here, we report the sensitization activity of these metal free dyes in terms of current–potential curve, open-circuit potential, fill factor, and overall solar energy conversion efficiency which have been evaluated under 100 mW cm?2 light intensity. We developed a strategy to improve the light harvesting of these conventional dyes by simple cationic exchange which was accompanied by a minimum of 30% increase in the cell photovoltaic conversion efficiency. Also, for Eosin B the binding to TiO2 apparently allows reduction of the –NO2 electron-withdrawing group to –NO2?. This provides a new interaction between the reduced nitro group and the TiO2 surface, reflecting an improvement in the overall DSSC performance reaching its maximum of 0.65% efficiency after light DSSC soaking. Factors that improve DSSC performance like aggregate inhibition, increment of the electrode's quasi-Fermi level and slight red shift in the absorption spectra of the tested anionic dyes were achieved by simple cationic exchange.
关键词： TiO2 sensitization,Cationic exchange,Photovoltaic conversion efficiency,Fluorone-based ionic liquids,Dye-sensitized solar cells
更新于2025-09-16 10:30:52
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A new uniformity coefficient parameter for the quantitative characterization of a textured wafer surface and its relationship with the photovoltaic conversion efficiency of monocrystalline silicon cells
摘要： A new parameter, the uniformity coefficient (UC), was proposed to overcome the difficulty in quantitatively characterizing the uniformity of the pyramidal textured surface of silicon wafers widely used for monocrystalline silicon cells (MSCs). The UC was defined based on the areal material ratio Smr(c) from the standard ISO 25178-2. First, the values of Smr(c) for MSC wafer surfaces with a uniform texture and an arbitrary texture were calculated. For the ideal uniform texture, Smr(c) was calculated using one pyramid assuming equal pyramids distributed over the wafer surface. For any arbitrary texture, based on the pyramidal geometrical structure, Smr(c) was calculated from the heights of pyramids extracted from their 2D projections. Second, the areas bounded by the Smr(c) curves with two coordinate axes were calculated accordingly. Then, the ratio of the two areas was defined as the UC. Fifteen kinds of monocrystalline silicon wafers were prepared by chemical texturing for 5 min, 15 min, 25 min, 35 min and 45 min with three groups of solutions, and the corresponding MSCs were fabricated. The UCs of the fifteen silicon wafers and the photovoltaic conversion efficiencies (PCEs) of the MSCs were tested. The relationships between the UC, texturing process (solution and time) and PCE were analyzed. The PCE increased monotonically with an increase in the UCs The silicon wafer obtained by texturing with 2% TMAH solution for 25 min had a textured surface with a maximum UC of 0.89, and the MSC exhibited a maximum PCE of 20.3%. The experimental results indicated that the UC is an effective parameter for the quantitative characterization of the pyramidal texture of silicon wafer surfaces and has a definite relationship with the PCE of the MSC. The UC is a useful and convenient measure for texturing process optimization.
关键词： Uniformity coefficient (UC),Quantitative characterization,Monocrystalline silicon cell (MSC),Pyramidal texture,Photovoltaic conversion efficiency (PCE),Areal material ratio Smr(c)
更新于2025-09-16 10:30:52
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Theoretical Analysis of Hybrid Dense-Array Concentrator Photovoltaic and Stirling Engine System
摘要： In this paper, we analyse the performance of newly proposed hybrid dense-array concentrator photovoltaic (CPV) and gamma type low temperature differential (LTD) Stirling engine. Schmidt Analysis was applied to compute the performance of LTD Stirling engine while computational fluid dynamic was employed to simulate the heat transfer in the CPV receiver. The simulated result was subsequently used to determine the power conversion efficiency of the hybrid system. Three major parameters have been considered to optimize the overall system performance including water inlet temperature, water flow rate, and CPV surface temperature. In our theoretical analysis, the highest efficiency of the hybrid system ranging 37.8 - 38.0 % can be achieved at water inlet temperature of 90°C. It has shown significant improvement by producing 10.1 -10.7 % extra energy as compared to the efficiency of CPV system without waste heat recovery.
关键词： waste heat recovery,low temperature differential Stirling engine,Concentrator photovoltaic,conversion efficiency,Schmidt analysis,non-imaging dish concentrator
更新于2025-09-12 10:27:22
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Photovoltaic Properties of an rGO/Pt Counter Electrode with AZO Photoanode for Dye-sensitized Solar Cells under Low Light Intensity
摘要： This study used reduced graphene oxide (rGO) applied to a platinum (Pt) counter electrode to improve light conversion efficiency. The study also used an Al-doped Zinc Oxide (AZO) nanosheet / TiO2 photoanode for the dye-sensitized solar cell (DSSC). Photovoltaic characteristics, electrochemical impedance spectroscopy (EIS), field-emission scanning electron microscopy (FE-SEM) and Raman spectroscopy were used to analyze DSSC. The different light intensities and photovoltaic characteristics were analyzed to determine optimal light intensity conditions. The unmodified Pt counter electrode was compared with the rGO/Pt counter electrode, photovoltaic conversion efficiency (η) increased from 3.60% to 4.04% due to the rGO modification as it possesses a higher specific surface area. Its low cost also makes it suitable for mass production. In addition, an AZO nanosheet / TiO2 photoanode was fabricated to form a double-layer structure in which photovoltaic conversion efficiency was 4.47 %. Finally, a DSSC with an AZO / TiO2 photoanode and rGO/Pt counter electrode was fabricated and had an photovoltaic conversion efficiency of 5.05 %. This study also analyzed the photovoltaic parameters of DSSC under different intensities, which shows the optimal photovoltaic conversion efficiency of 5.54% under 30mW / cm2.
关键词： photovoltaic conversion efficiency,low light intensity,Al-doped Zinc Oxide (AZO),hydrothermal synthesis,Dye-sensitized solar cell (DSSC),reduced graphene oxide (rGO)
更新于2025-09-12 10:27:22