Improving the power conversation efficiency of dyesensitized solar cells (DSSCs) has become a challenge and a matter of interest for researchers. Designing a simple device structure with better performance by a cost-effective fabrication technique is essential for photovoltaic technology. This study emphasizes an alternative hybrid composite photoanode material for the DSSC devices. Pristine Zn 2 SnO 4 and Zn 2 SnO 4 -SnO 2 and Zn 2 SnO 4 -ZnO composites were synthesized by facile solid-state calcination to prepare the photoanode for DSSCs. The structural, surface morphological, optical, and band structural properties of the synthesized samples were studied. An attempt has been made to correlate the power conversion efficiency of the fabricated devices with the investigated properties. The X-ray diffraction analysis confirms the presence of multiphases that depend on the stoichiometric ratio of precursor materials. The surface morphology analysis reveals that the Zn 2 SnO 4 -SnO 2 and Zn 2 SnO 4 -ZnO composites exhibit microsheet and microrod structures, respectively. The composite materials show a higher amount of dye loading, leading to better performance than the pristine Zn 2 SnO 4 sample. A better band matching of the synthesized composite materials with other layers provides a higher carrier density. The composite photoanodes exhibit higher efficiency (6.26% for Zn 2 SnO 4 -SnO 2 and 4.48% for Zn 2 SnO 4 -ZnO) than the pristine Zn 2 SnO 4 photoanode (3.76%). The results indicate that the Zn 2 SnO 4 -based composites can be potential materials for photoanode applications.
Solar selective coating with good thermal stability is the primary requirement for a concentrated solar power (CSP) plant to function with better photothermal efficiency. In recent years, ultra-high-temperature ceramic-based coatings have been explored as potential materials for solar selective coatings. In this context, NbB 2 /Nb(BN)/Al 2 O 3 tandem absorber coating was designed to be fabricated on a stainless-steel substrate by the radio frequency magnetron sputtering of spark plasma sintered ceramic target. In the bulk form, the NbB 2 ceramic exhibits high solar absorptance (α = 0.756) and thermal emissivity (ε = 0.43), whereas the amorphous single NbB 2 coating exhibits α/ε = 0.716/0.13. Reactive sputtering of NbB 2 in nitrogen produced a semi-transparent coating with an optical bandgap of ∼2.80 eV and was used as the secondary absorber layer. Raman and X-ray photoelectron spectroscopy analyses reveal mild oxygen incorporation in the absorber layers. The developed SS/NbB 2 /Nb(BNO)/Al 2 O 3 tandem absorber exhibits a good solar absorptance of 0.950 and a moderate thermal emissivity of 0.15 at room temperature. The coatings exhibited good thermal stability when heated in vacuum for 5 h up to 700 • C, and the selectivity (α/ε) remains above 6. The present work shows the possibility of exploring NbB 2 -based tandem absorber coatings for CSP applications.
This study describes the bismuth vanadate thin films (BVO) as an alternative electron transport layer for widely used LiF for the electron‐only device (EODs) application. The BVO thin film is spin‐coated on a glass substrate as a function of solution concentration. The X‐ray diffraction pattern of the film deposited from 10 × 10−3m (BVO1) to 150 × 10−3m (BVO4) solution concentration possesses the BiVO4 phase with a tetragonal structure, whereas the film deposited at 200 × 10−3m (BVO5) shows the Bi2V4O11 phase with an orthorhombic structure. The surface morphology of the films confirms nanoparticle formation with the lower surface roughness. The UV–visible studies show the average transmittance of the films decreases with increasing solution concentration and the maximum average transmittance of 86% is obtained in BVO1 film. This oxygen vacancy promotes the charge transfer process very effectively. The EODs fabricated using BVO1 film (BiVO4 phase) exhibits the maximum current density of 59.2 mA cm−2 with a turn‐on voltage of 4.09 V, whereas the EOD device fabricated using BVO5 film (Bi2V4O11 phase) possesses the current density of 5.9 mA cm−2 with a turn‐on voltage of 4.09 V. Hence, the fabricated EODs using the BVO electron transport layer shows applicability in the OLED device.
Enhancing the performance of perovskite solar cells (PSCs) is one of the
prime concerns of researchers worldwide. For PSC devices, it is
essential to develop the individual layer efficiently and
cost-effectively. This work emphasizes the possibility of employing
Zn-Sn oxide-based composite materials as an alternative electron
transport layer (ETL) in PSC devices. Pristine Zn SnO
(ZTO), composite ZTO-ZnO, and ZTO-SnO
heterostructure-based ETL were prepared by simple
solid-state calcination technique and proposed as an alternative for the
TiO photoanode used in the PSC devices. The power
conversion efficiency of the designed PSC was studied based on
crystallinity, morphology, cross-section, roughness, contact angle, work
function, and Raman analysis of the ETL material. TEM analysis confirms
the phase pure ZTO and heterostructure formation as a function of
material stoichiometry. Compared to the pristine ZTO, the ZTO-ZnO and
ZTO-SnO composites have an enhanced PSC performance.
The ZTO-SnO composites exhibit better band matching
and charge transfer behavior with the perovskite layer than the pristine
ZTO and ZTO-ZnO composites. ZTO-SnO ETL-based PSC
device displays a maximum efficiency of 15.6 %, while ZTO-ZnO shows a
maximum efficiency of 13.1 %, which is more than 10.5 % for the
pristine ZTO. The results indicate that Zn SnO
-based composites can be suitable for ETL in PSC device
fabrication.
Multilayer solar selective absorber coatings have been developed in the last few decades. The thermal stability in terms of microstructure gives an insightful understanding of the optical properties of such coatings. In this context, we extensively utilized transmission electron microscopy (TEM) analysis to establish the thermal stability of TiB 2 /Ti(B,N)/SiON/SiO 2 coating, under thermal cycling/continuous heating to 500 • C in vacuum for 250 h. In particular, this work reports the variation in the solar absorptance of TiB 2 /Ti(B,N)/SiON/SiO 2 coating with different angles of incidence of the solar radiation. Extensive analysis using the TEM technique reveals the presence of oxide interlayers that act as diffusion barrier layers to enhance the thermal stability of the coating.Computational simulation using SCOUT software validates the measured reflectance spectrum of the developed multilayer coating. The minor changes in absorptance and emissivity after heat treatment in vacuum at 500 • C, together with high solar absorptance over a broad angular variation, establish the potential application of TiB 2 /Ti(B,N)/SiON/SiO 2 as a selective coating in concentrated solar power systems.
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