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Highlights in Applied Mineralogy || 4. Microstructure analysis of chalcopyrite-type Cu2ZnSe4 and kesterite-type Cu2ZnSnSe4 absorber layers in thin film solar cells
摘要： Thin film solar cells equipped with polycrystalline compound semiconductors as functional layer for light absorption have continuously been improved in terms of solar energy conversion efficiency, such that they became a competitive alternative to well-established silicon-based solar cells. In 1905, Einstein published a comprehensive, physical description of the photoelectric effect [1] and thus provided the theoretical framework for upcoming research of photovoltaic technologies. The emergence of photovoltaic devices, however, only started about 50 years later, and for several decades, it persisted a niche technology mainly for aerospace applications. Among others, silicon (Si) was known to belong to the group of (extrinsic) elemental semiconductors, and due to its abundance, it was the very first absorber material to be used in solar cells. Triggered by the oil crisis in the 1970s, the research of solar energy conversion technologies finally got a tremendous stimulus. As a result, research not only of silicon-based solar cells but also of other absorber layer materials based on compound semiconductors have been much more extensively endeavored. The latter were also brought into focus in order to address some severe drawbacks of silicon-based solar cells. First of all, the high energy consumption in fabricating single crystal silicon results in a quite long energy amortization time. In addition, the requirements on crystallinity and purity are extremely high while a considerable amount of material is wasted upon slicing silicon wafers. Also, during the growth of silicon single crystals a certain concentration of dopants has to be incorporated in order to induce either extrinsic p-type or n-type conductivity. Despite the energy of the band gap of silicon fitting quite well with the optimal energy determined by the solar spectrum, silicon is an indirect semiconductor whose photonic electron transition from the valence band to the conduction band needs to be assisted by a phononic momentum transfer. This requirement of coincidence between a photon of appropriate energy being absorbed and a phonon transferring impulse to the electron leads to a reduced probability of events of photoelectric charge carrier generation. Correspondingly, the absorber thickness must be augmented in order to compensate the low absorption coefficient. These aforementioned issues, eventually, gave rise to reconsider photovoltaic technologies, being both economical and ecological reasonably applicable in a more widely spread manner. These demands have paved the way for thin film solar cell technologies using compound semiconductors. Those compound semiconductors are intrinsically conductive, and they possess a higher absorption coefficient due to direct electron band transitions (Fig. 4.1).
关键词： kesterite-type,chalcopyrite-type,absorber layer materials,light absorption,microstructure analysis,photovoltaic technologies,solar energy conversion efficiency,compound semiconductors,thin film solar cells,silicon-based solar cells
更新于2025-09-16 10:30:52
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Simulative Parametric Study on Heterojunction Thin Film Solar Cells Incorporating Interfacial Nanoclusters Layer
摘要： Organic solar cells deal with small organic molecules for absorption of light at low cost and high efficiency. In this paper, we have analyzed the photovoltaic (PV) characteristics of double heterojunction solar cell that consists of copper phthalocyanine (CuPc) and 3,4,9,10-perylenetetracarboxylic bis-benzimidazole (PTCBI) thin films. Here, CuPc and PTCBI layers are combined by an interfacial layer consisting of nanoscale dots. Different plasmonic materials (i. e. Ag, Au, and graphene) are selected as alternative nanoscale dot layer to examine their effect on solar cell performance. Further, the solar cell performance is also examined via variation in active layer thickness. The choice of interfacial layer material and variation in active layer thickness offer grounds for future efficient PV cells.
关键词： energy conversion efficiency,plasmonic materials,CuPc/PTCBI solar cells,excitons
更新于2025-09-16 10:30:52
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Interfacing boron monophosphide with molybdenum disulphide for an ultrahigh performance in thermoelectrics, 2D excitonic solar cells and nanopiezotronics
摘要： Stable ultrathin 2D van der Waals (vdW) heterobilayer, based on the recently synthesized boron monophosphide (BP) and the widely studied molybdenum disulphide (MoS2), has been systematically explored for the conversion of waste heat, solar energy and nanomechanical energy into electricity. It shows a gigantic figure of merit (ZT) > 12 (4) for p (n)-type doping at 800 K, which is the highest ever reported till date. At room temperature (300 K), ZT reaches 1.1 (0.3) for p(n)-type doping which is comparable to experimentally measured ZT=1.1 on PbTe-PbSnS2 nanocomposite at 300 K. While it outweighs the Cu2Se-CuInSe2 nanocomposite (ZT=2.6 at 850 K) and the theoretically calculated ZT = 7 at 600 K on silver halides. Lattice thermal conductivity (???? ~ 49 Wm-1K-1) calculated at room temperature is lesser than that of black phosphorene (78 Wm-1K-1) and arsenene (61 Wm-1K-1). The nearly matched lattice constants in the commensurate lattices of the constituent monolayers helps to preserve the direct band gap at the K point in the type II vdW heterobilayer of MoS2/BP, where BP and MoS2 serve as donor and acceptor materials respectively. An ultrahigh carrier mobility ~ 20 × 103 cm2V-1s-1 is found, which exceeds that of previously reported transition metal dichalcogenide based vdW heterostructures. The exciton binding energy (0.5 eV) is close to that of MoS2 (0.54 eV) and C3N4 (0.33 eV) single layers. The calculated power conversion efficiency (PCE) in monolayer MoS2/BP heterobilayer exceeds 20%. It surpasses the efficiency in MoS2/p-Si heterojunction solar cells (5.23%) and competes with the theoretically calculated ones, listed in the manuscript. Furthermore, high optical absorbance (~105 cm-1) of visible light and small conduction band offset (0.13 eV) makes MoS2/BP very promising in 2D excitonic solar cells. Out-of-plane piezoelectric strain coefficient, ??33 ~ 3.16 pm/V, is found to be enhanced four-fold (~14.3 pm/V) upon applying 7% vertical compressive strain on the heterobilayer, which corresponds to ~1 kBar of hydrostatic pressure. Such a high out-of-plane piezoelectric coefficient, which can tune top-gating effects in ultrathin 2D nanopiezotronics, is a relatively new finding. As BP has been synthesized recently, experimental realization of the multifunctional, versatile MoS2/BP heterostructure would be highly feasible.
关键词： first-principles calculations,piezoelectricity,thermoelectricity,solar energy conversion efficiency,excitonic solar cells
更新于2025-09-12 10:27:22
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Photoconversion efficiency of Titania solar cells co-sensitized with natural pigments from cochineal, papaya peel and microalga Scenedesmus obliquus
摘要： Three natural pigments obtained from cochineal, papaya peel, and the microalga Scenedesmus obliquus were tested as sensitizers in dye sensitized Titania solar cells. The absorption characteristics of the pigments and the photoelectrochemical parameters were studied to determine the photoconversion efficiency of the cells. The interfacial charge transport processes present in the individually sensitized and the co-sensitized cells were determined by electrochemical impedance spectroscopy (EIS). The highest efficiencies achieved for individual pigments after testing a set of different concentrations were 0.228, 0.093 and 0.064% using cochineal, papaya peel extract and Scenedesmus obliquus extract respectively. 0.36% conversion efficiency was reached in the sensitized cell using a combination of the three pigments. The efficiency reached is in the range of those reported for natural pigments. Papaya peel extract and chlorophylls from Scenedesmus obliquus were examined for the first time as possible sensitizers in DSSC.
关键词： photoelectrochemical parameters,energy conversion efficiency.,natural pigments,DSSC,mixed extracts,electrochemical impedance spectroscopy (EIS)
更新于2025-09-12 10:27:22
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Enhancement of target normal sheath acceleration in laser multi-channel target interaction
摘要： Target-normal sheath acceleration (TNSA) of ions by >100-fs relativistic laser pulses irradiating a multichannel target consisting of a row of parallel long wires and a plane back foil is studied. Two-dimensional particle-in-cell simulations show that the laser light pulls out from the wires a large number of dense hot attosecond electron bunches, which are synergetically accelerated forward by the relativistic ponderomotive force of the laser as well as the longitudinal electric field of a transverse magnetic mode that is excited in the vacuum channels between the wires. These electrons are characterized by a distinct two-temperature energy spectrum, with the temperature of the more energetic electrons close to twice the ponderomotive potential energy. After penetrating through the foil, they induce behind its rear surface a sheath electric field that is both stronger and frontally more extended than that without the channels. As a result, the TNSA ions have much higher maximum energy and the laser-to-ion energy conversion efficiency is also much higher. It is found that a laser of intensity 1.37 × 1020 W/cm2, duration 165 fs, and energy 25.6 J can produce 85 MeV protons and 31 MeV/u carbon ions, at 30% laser-to-ion energy conversion efficiency. The effects of the channel size and laser polarization on the TNSA ions are also investigated.
关键词： laser-plasma interaction,ion acceleration,Target-normal sheath acceleration,particle-in-cell simulations,TNSA,laser-to-ion energy conversion efficiency
更新于2025-09-12 10:27:22
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A study nanocrystalline TiO 2 based on dye sensitized solar cells with quasi solid state electrolytes
摘要： A quasi solid state electrolytes can be done by adding potassium iodide (KI) and iodine (I2) into quasi solid state electrolytes. Consisting 1,2,4,5–tetrakisbromomethyl benzene (TB), ? –butyrolactone (GBL), propylene carbonate (PC), and ethylene carbonate (EC) gelated with sample 1, 2, 3 and 4. Potassium iodide salt poorly soluble in liquid electrolyte, but can dissolve completely in quasi solid state electrolytes. The dye sensitized solar cell (DSSCs) with the quasi solid state electrolytes were fabricated. The results showed that the energy conversion efficiency of light to electricity were 0.052 %, 0.126 %, 0.121 % and 0.125 %., respectively, under irradiation of 80 mW/cm2. The performance of the dye sensitized solar cell with quasi solid state electrolytes is more stable than that of liquid electrolytes.
关键词： TiO2,dye sensitized solar cell,potassium iodide,iodide salts,quasi solid state electrolytes,energy conversion efficiency
更新于2025-09-12 10:27:22
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Performance optimization of a photovoltaic/thermal collector using microencapsulated phase change slurry
摘要： In a photovoltaic/thermal (PV/T) collector, a portion of absorbed solar energy is transformed into electrical energy, and the remaining part is transformed into thermal energy. Increasing waste heat collection and energy conversion rates are important to improve the performance of the PV/T collector. The utilization of microencapsulated phase change slurry (MPCS) in a PV/T collector to cool photovoltaic modules is an effective way, and electrical and thermal performances of the collector are improved. To investigate influences of operating parameters on performances of PV/T collector, numerical simulation is put into effect to analyze influences of the mass fraction of MPCS on the collector performance. The influences of MPCS mass flow rate and collector channel height on collector performances are also studied. When the flow rate is 0.005 kg/s and the channel height is 0.010 m, the PV/T collector obtains the best net efficiency with a MPCS mass concentration of 20 wt%. But electrical efficiency difference between 15 and 20 wt% is not obvious. With the growth in mass fraction, PV temperature drops more and more slowly because outlet fluid has not fully melt. Take PV/T collector performances into consideration, 15 wt% MPCS is a better choice to cool photovoltaic modules.
关键词： microencapsulated phase change slurry,photovoltaic/thermal collector,electrical and thermal performances,energy conversion efficiency
更新于2025-09-12 10:27:22
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Performance Evaluation of Single-Junction Indoor Photovoltaic Devices for Different Absorber Bandgaps Under Spectrally Varying White Light-Emitting Diodes
摘要： In this article, we present a detailed theoretical study to predict performance characteristics of single-junction indoor photovoltaic (PV) devices operated under white light emitting diodes (LEDs) having different spectral characteristics. Efficiency limits of both ideal and practical PV converters have been evaluated considering illumination by commercially available white LEDs. The obtained results have been generalized for white LED sources having a wide range of correlated color temperatures (CCTs) and fraction of blue in their corresponding spectrum. Depending on bandgap of the absorber material, both positive and negative correlations are observed between photon conversion efficiency of PV devices and CCT values of the white LED sources. For material bandgaps of ～1.5 eV or lower, higher photon conversion efficiencies are obtained for warm glow white LEDs. On the contrary, white LEDs characterized to emit cool light are found to be more conducive for PV devices having absorber layer bandgaps of ～2 eV or higher. The observed characteristics have been explained in terms of linewidth of the main emission peak and relative intensity of blue emission peak of the irradiating white LED spectrum. Based on the analysis of photon yield, three distinct bandgap ranges of the PV absorber material have also been identified, each of which represents different dependence of PV device performances on the white LED spectral characteristics. These results in effect provide the necessary guidelines for designing homojunction, heterojunction, or tandem PV devices suitable for operation under different practical white LED sources.
关键词： red-green-blue (RGB) white light emitting diodes (LEDs),energy conversion efficiency,photon yield,Correlated color temperature,indoor photovoltaic (PV)
更新于2025-09-12 10:27:22
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Analysis and optimization of passive cooling approach for free-standing photovoltaic panel: Introduction of slits
摘要： One of the major issues related to market available silicon based photovoltaic (PV) technologies is the performance drop caused by relatively high PV panel operating temperatures. The proper cooling of PV panels can reduce performance degradation and increase the lifetime of convectional PV panels. This paper investigates architecture modifications to market available silicon PV panels with the introduction of slits on the PV panel surface, which enables the passive cooling of PV panels. Two different arrangements of slits were numerically investigated and followed with the optimization approach. A developed numerical model was derived from the referent numerical model that was experimentally validated. For each considered scenario, a detailed flow and thermal analysis was performed which included optimization regarding minimum average PV cell temperatures. The considered slit types differ with slit orientation, i.e. parallel to PV panel tilt-axis (type-A) and perpendicular to PV panel tilt-axis (type-B). In both cases, a detailed analysis and optimization required ~100 CFD simulations to investigate the effects of different slit sizes and all wind directions. Overall, using the considered slit modifications, the average PV cell temperature could be decreased up to 3 °C, where effective cooling with the proposed modification is only reasonable for wind speeds up to 5 m/s.
关键词： Energy conversion efficiency,Renewable energy,Photovoltaics,Numerical analysis,Passive cooling
更新于2025-09-11 14:15:04
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A porous Ni-O/Ni/Si photoanode for stable and efficient photoelectrochemical water splitting
摘要： Excellent photoelectrochemical activity was demonstrated for an easily prepared porous Ni-O/Ni/Si photoanode with an onset potential of 0.93 VRHE, a photocurrent of 39.7 mA cm?2 at 1.23 VRHE, an energy conversion efficiency of 3.2% and a stability above 100 h.
关键词： stability,water splitting,porous Ni-O/Ni/Si photoanode,energy conversion efficiency,photoelectrochemical
更新于2025-09-04 15:30:14