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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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Plasmonic Response of Light-Activated, Nano-Gold Doped Polymers
摘要： Incorporation of metallic nanoparticles (NPs) in polymer matrix has been used to enhance and control dissolution and release of drugs, for targeted drug delivery, as antimicrobial agents, localized heat sources, and for unique optoelectronic applications. Gold NPs in particular exhibit a plasmonic response that has been utilized for photothermal energy conversion. Because plasmonic nanoparticles typically exhibit a plasmon resonance frequency similar to the visible light spectrum, they present as good candidates for direct photothermal conversion with enhanced solar thermal efficiency in these wavelengths. In our work, we have incorporated ~3-nm-diameter colloidal gold (Auc) NPs into electrospun polyethylene glycol (PEG) fibers to utilize the nanoparticle plasmonic response for localized heating and melting of the polymer to release medical treatment. Auc and Auc in PEG (PEG+Auc) both exhibited a minimum reflectivity at 522 nm or approximately green wavelengths of light under ultraviolet-visible (UV-Vis) spectroscopy. PEG+Auc ES fibers revealed a blue shift in minimum reflectivity at 504 nm. UV-Vis spectra were used to calculate the theoretical efficiency enhancement of PEG+Auc versus PEG alone, finding an approximate increase of 10 % under broad spectrum white light interrogation, and ~14 % when illuminated with green light. Auc enhanced polymers were ES directly onto resistance temperature detectors and interrogated with green laser light so that temperature change could be recorded. Results showed a maximum increase of 8.9 °C. To further understand how gold nanomaterials effect the complex optical properties of our materials, spectroscopic ellipsometry was used. Using spectroscopic ellipsometry and modeling with CompleteEASE? software, the complex optical constants of our materials were determined. The complex optical constant n (index of refraction) provided us with optical density properties related to light wavelength divided by velocity, and k (extinction coefficient) was used to show the absorptive properties of the materials.
关键词： spectroscopic ellipsometry,photothermal energy conversion,polyethylene glycol,metallic nanoparticles,plasmonic response,UV-Vis spectroscopy,gold NPs,electrospun fibers
更新于2025-09-16 10:30:52
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Synthesis and characterization of novel tetra anchoring A2-D-D-D-A2 architecture sensitizers for efficient dye-sensitized solar cells
摘要： Novel metal free organic dyes coded TET(RA)4, TET(CA)4, and TET(QA)4 were designed, synthesized, and characterized as effective sensitizers for dye sensitized solar cells (DSSCs). These new push-pull sensitizers used a strong electron donor consisting of 3,4-ethylenedioxythiophene and two triphenylamine molecules connected together to form a TPA-EDOT-TPA (TET) motif, which is directly connected to tetra anchoring groups (A) without any π-spacers to construct A2-D-D-D-A2 architecture, three different anchoring series, viz. rhodanine-3-acetic acid (RA), cyanoacetic acid (CA), and 2-methyl quinoline-6-carboxylic acid (QA) were employed to investigate the influence of anchoring moieties on the electrochemical, thermodynamic, kinetics, and photovoltaic efficiency of DSSCs. The DSSCs devices showed a maximum overall power conversion efficiency (PCE) = 5.13%, short-circuit current density (JSC) = 12.71 mA.cm?2, open circuit voltage (VOC) = 0.62 V, and fill factor (FF) = 65.36% with a maximum incident photon conversion efficiency (IPCE) = 75% for TET(QA)4. The optical and electrochemical studies showed that TET(QC)4 achieved higher electron injection free energy (ΔG°inj) into CB edge of TiO2 as well as high recombination resistance (Rrec) compared to TET(RA)4, and TET(CA)4, which explains the outstanding charge separation and superior power conversion efficiency (PCE) of TET(QC)4 possessing quinoline-6-carboxylic acid (QC) anchoring group. Molecular modeling calculations using DFT and TD-DFT showed effective charge separation, where HOMO is delocalized over the donor scaffold (TPA-EDOT-TPA), and the LUMO is delocalized over only two anchoring groups on the same side of the donor system, which provides strong HOMO-LUMO overlap as well as intimate electronic coupling with TiO2 nanoparticle surface for electron injection. Further, the calculated values of the energy gaps (E0-0) and ground/excited stated oxidation potentials were in perfect agreement with the experimental results.
关键词： Sensitizers,Molecular modeling,Photovoltaics,Synthesis,Energy conversion
更新于2025-09-16 10:30:52
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Soft-chemistry assisted strong metal-Support interaction on designed plasmonic core-shell photocatalyst for enhanced photocatalytic hydrogen production
摘要： Engineering photocatalysts based on gold nanoparticles (AuNPs) has attracted great attention for the solar energy conversion due to their multiple and unique properties. However, boosting the photocatalytic performance of plasmonic materials for H2 generation have reached some limitation. In this study, we propose a soft-chemistry method for the preparation of strong metal-interaction support (SMSI) to enhance the photocatalytic production of H2. The TiO2 thin overlayer covering finely dispersed AuNPs (forming an SMSI) boost the photocatalytic generation of hydrogen, compared to AuNPs deposited at the surface of TiO2 (labelled as a classical sytem). The pathway of the charge carriers’ dynamics occurred regarding the system configuration are found to be different. The photogenerated electrons are collected by AuNPs in a classical system and act as an active site, while, unconventionally, they are injected back in the titania surface for an SMSI photocatalyst making the system highly efficient. Additionally, the adsorption energy of methanol, theoretically estimated using density functional theory (DFT) methodology, is lower for soft-chemistry SMSI photocatalyst accelerating the kinetics of photocatalytic hydrogen production. SMSI obtained by soft-chemistry is an original concept for highly efficient photocatalytic materials, where the photons-to-energy conversion remains a major challenge.
关键词： hydrogen production,photocatalysts,solar energy conversion,gold nanoparticles,TiO2,SMSI
更新于2025-09-16 10:30:52
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Multi-bandgap Solar Energy Conversion via Combination of Microalgal Photosynthesis and Spectrally Selective Photovoltaic Cell
摘要： Microalgal photosynthesis is a promising solar energy conversion process to produce high concentration biomass, which can be utilized in the various fields including bioenergy, food resources, and medicine. In this research, we study the optical design rule for microalgal cultivation systems, to efficiently utilize the solar energy and improve the photosynthesis efficiency. First, an organic luminescent dye of 3,6-Bis(4′-(diphenylamino)-1,1′-biphenyl-4-yl)-2,5-dihexyl-2,5-dihydropyrrolo3,4-c pyrrole -1,4-dione (D1) was coated on a photobioreactor (PBR) for microalgal cultivation. Unlike previous reports, there was no enhancement in the biomass productivities under artificial solar illuminations of 0.2 and 0.6 sun. We analyze the limitations and future design principles of the PBRs using photoluminescence under strong illumination. Second, as a multiple-bandgaps-scheme to maximize the conversion efficiency of solar energy, we propose a dual-energy generator that combines microalgal cultivation with spectrally selective photovoltaic cells (PVs). In the proposed system, the blue and green photons, of which high energy is not efficiently utilized in photosynthesis, are absorbed by a large-bandgap PV, generating electricity with a high open-circuit voltage (Voc) in reward for narrowing the absorption spectrum. Then, the unabsorbed red photons are guided into PBR and utilized for photosynthesis with high efficiency. Under an illumination of 7.2 kWh m?2 d?1, we experimentally verified that our dual-energy generator with C60-based PV can simultaneously produce 20.3 g m?2 d?1 of biomass and 220 Wh m?2 d?1 of electricity by utilizing multiple bandgaps in a single system.
关键词： Photobioreactor,Spectrally selective photovoltaic cell,Solar energy conversion,Dual-energy generator,Microalgal photosynthesis
更新于2025-09-12 10:27:22
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Interfacial Engineering in Functional Materials for Dye‐Sensitized Solar Cells || Graphitic Carbon Nitride Based Nanocomposites as Photoanodes
摘要： Owing to their unique properties, nanocomposites, nanostructures, and nanomaterials are playing a key role in energy conversion and in energy storage applications. In recent years, carbon-based nanostructures are used to meet the future energy demands. Nanostructured carbon nitrides (C3N4) are very attractive candidates for energy-based devices due to its high hardness, low friction coefficient, and steadfast chemical inertness. It has a great potential in solving the issues related to energy and environmental applications. Graphitic carbon nitride (g-C3N4) is one among the carbon-based nanostructures which has attracted enormous attention in green technologies for arresting solar energy, energy storage, supercapacitor, fuel cells, electrocatalysis, and environmental remediation as well as for electronic and composite industry. g-C3N4 is a well-known polymeric materials mainly consisting of carbon, nitrogen, and is also one of the oldest material discovered in 1843. It is considered as an artificial polymer in the scientific literature [1]. Its structure is shown in Figure 12.1.
关键词： Nanocomposites,Energy Storage,Energy Conversion,Photoanodes,Graphitic Carbon Nitride
更新于2025-09-12 10:27:22
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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