Selective contact annealing is developed to improve the performance of bifacial‐grid III–V top cells bonded on glass by epoxy resin for Si‐based tandem solar cells. The annealing method can minimize ...the damage to the bonding layer and is compatible with the industrial evaporation technique for contact fabrication. The improvement of the front contact quality by selective annealing treatments is demonstrated through optical and electrical characterization which shows a significantly enhanced III–V device performance. Furthermore, a fitting model is established to reveal the mechanism underlying the performance improvement through the reduction of contact resistances and the bad contact area. Herein, an effective annealing approach to fabricate high‐quality metal–semiconductor contacts for devices with poor thermal resistivity is demonstrated, which can be used in polymer‐bonded top cells in Si‐based tandem solar cells and other flexible optoelectronic devices on polymer substrates.
Selective contact annealing is developed to improve the performance of bifacial‐grid III–V top cells bonded on glass by epoxy resin for Si‐based tandem solar cells. This method can minimize the damage to the bonding layer and is compatible with the industrial evaporation technique for contact fabrication, allowing high‐quality metal–semiconductor contacts for devices with poor thermal resistivity.
The anomalous optoelectronic properties of a quasi‐vertical orientated Chalcostibite CuSbS2 thin film synthesized on glass substrate are studied in detail. Two well‐separated absorption edges of ...CuSbS2 are identified by photothermal‐deflection spectroscopy (PDS) at 1.48 and 0.90 eV. The formation mechanism of the 0.9 eV infrared edge is found to be crystal orientation related. The properties of the 0.9 eV absorption edge are subject to detailed investigation using temperature‐dependent photoluminescence (TDPL) characterization, which attribute the origin of this phenomenon to a deep‐level defect state near the mid‐bandgap of CuSbS2.
In quasi‐vertical orientated Chalcostibite CuSbS2 thin films, two well‐separated absorption edges are identified by photothermal‐deflection spectroscopy (PDS) at 1.48 and 0.90 eV. Using temperature‐dependent photoluminescence (TDPL) characterization, the anomalous absorption edge of the 0.9 eV is attributed to be a crystal‐orientation‐related deep‐level defect state near the mid‐bandgap of CuSbS2.
The anomalous optoelectronic properties of a quasi‐vertical orientated Chalcostibite CuSbS
2
thin film synthesized on glass substrate are studied in detail. Two well‐separated absorption edges of ...CuSbS
2
are identified by photothermal‐deflection spectroscopy (PDS) at 1.48 and 0.90 eV. The formation mechanism of the 0.9 eV infrared edge is found to be crystal orientation related. The properties of the 0.9 eV absorption edge are subject to detailed investigation using temperature‐dependent photoluminescence (TDPL) characterization, which attribute the origin of this phenomenon to a deep‐level defect state near the mid‐bandgap of CuSbS
2
.
We present a high-temperature Cu 2 ZnSnSe 4 coevaporation study, where solar cells with a power conversion efficiency of 7.1% have been achieved. The process is monitored with laser light scattering ...in order to follow the incorporation of the Sn into the film. We observe the segregation of ZnSe at the Mo/CZTSe interface. Optical analysis has been carried out with photoluminescence and spectrophotometry. We observe strong band tailing and a bandgap, which is significantly lower than in other reported efficient CZTSe absorbers. The photoluminescence at room temperature is lower than the bandgap due to the existence of a large quantity of tail states. Finally, we present effects of low-temperature postannealing of the absorbers on ordering of the Cu/Zn atoms in CZTSe and solar cell parameters. We observe strong changes in all solar cell parameters upon annealing. The efficiency of the annealed devices is significantly reduced, although ordering is improved compared with ones made from nonannealed absorbers.
We apply spectroscopic ellipsometry (SE) to identify secondary phases in Cu
ZnSnSe
(CZTSe) absorbers and to investigate the optical properties of CZTSe. A detailed optical model is used to extract ...the optical parameters, such as refractive index and extinction coefficient in order to extrapolate the band gap values of CZTSe samples, and to obtain information about the presence of secondary phases at the front and back sides of the samples. We show that SE can be used as a non-destructive method for detection of the secondary phases ZnSe and MoSe
and to extrapolate the band gap values of CZTSe phase.
Highly conductive nominally undoped ZnO (b-ZnO) films represent an attractive alternative for ZnO:Al windows employed in thin film solar cells. In order to assess their suitability for the PV ...industry, we examine here their stability in various environments. We show that the b-ZnO films can exhibit comparable stability to ZnO:Al films in both ambient and heated air. However, b-ZnO films degrade faster in accelerated open damp heat (DH) conditions, which can be related to their columnar microstructure. Finally, a b-ZnO multilayer coating with an improved environmental stability is presented.
Les nanostructures d'oxydes métalliques jouent un rôle essentiel dans les cellules photovoltaïques à colorants, puisque ces matériaux permettent la réalisation du contact électrique transparent en ...face avant et de la photoanode. L'oxyde stannique (SnO2) et l'oxyde de zinc (ZnO) ont été employés respectivement, car leurs propriétés optiques, électroniques et structurales sont particulièrement bien adaptées aux cellules solaires à colorant. Le contact électrique transparent, obtenu par pyrolyse d'aérosol, se présente sous forme d'une couche mince de SnO2 dopé par du fluor composée de grains nanométriques. Les propriétés électriques et optiques de ce composant ont été optimisées en vue de son intégration dans des cellules à colorants. Une étude approfondie du transport électronique au sein de la couche a permis de quantifier l'influence des différents mécanismes de diffusion suivant les cas considérés. La photoanode a été réalisée, directement à la surface de la couche mince de SnO2, par dépôt chimique de nanofils de ZnO à partir de précurseurs en phase vapeur. Le diamètre et la densité surfacique des nanofils sont contrôlés respectivement par les conditions de croissance et le degré d'oxydation du substrat. Les photoanodes à base de nanofils ont été intégrées dans des cellules à colorant. La limitation des performances de ces cellules est due à la faible surface développée par le ZnO qui conduit à la fixation d'une trop faible quantité de colorant à la surface de ce dernier. Afin de remédier à ce problème, des nanoparticules de ZnO ont été élaborées par bain chimique à la surface des nanofils. Les cellules solaires à base de structures composites présentent des performances supérieures à celles réalisées à partir de nanofils ou de nanoparticules. Les photoanodes composites permettent d'obtenir à la fois un transport efficace des électrons et de développer une surface importante et de ce fait, elles présentent des performances prometteuses.
Metallic oxide nanostructures play a critical role in dye-sensitized solar cells as front transparent electrodes and photoanodes. The use of stannic oxide (SnO2) and zinc oxide (ZnO) have been motivated by their particularly suitable structural, electrical and optical properties for dye-sensitized solar cells. Fluorine doped-SnO2 transparent electrodes have been deposited by spray pyrolysis in the form of thin films and consist of nanoscale grains. Their optical and electrical properties have been optimized in order to integrate them into dye-sensitized solar cells. The electron transport has been investigated in details and the influence of each scattering mechanism has quantitatively been assessed. ZnO photoanodes have directly been grown on the SnO2 surface by chemical vapor deposition in the form of nanowires. The nanowire diameter and surface density have been controlled by the growth conditions and the substrate surface oxidation, respectively. The nanowire-based photoanodes have subsequently been integrated into dye-sensitized solar cells. The relatively low efficiency of these cells has been found to be due to the small ZnO surface area, which limits the amount of dye anchored to its surface. In order to circumvent this limitation, ZnO nanoparticles have been deposited on the nanowire surface by chemical bath deposition. The nanocomposite photoanodes lead to the fabrication of dye-sensitized solar cells with promising efficiency by combining both efficient electron transport and high developed surface area.
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