Next Generation Multilayer Graded Bandgap Solar Cells

Ojo, A. A.; Cranton, Wayne; Dharmadasa, I. M.

doi:10.1007/978-3-319-96667-0

Cited by 35 publications

(57 citation statements)

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“…It is captivating that the observed PEC trend is somewhat similar to that of the EDX spectra summary in Figure 9c. This is because one of the predominant factors determining the electrical conduction type is the atomic compositional ratio of the constituent elements, with Te-richness in CdTe resulting in p-type and Cd-richness resulting in n-type conduction type [18,34,35]. Other factors include the heat treatment parameters (such as duration, temperature), preliminary atomic composition of Cd and Te, the concentration of CdCl 2 or other dopants utilized in treatment, the structure of the defects in the material, and the initial conductivity type of the material [10,17,24,38].…”

Section: Discussionmentioning

confidence: 99%

“…The glass/fluorine-doped tin oxide (g/FTO) substrates utilized as the working electrode were cut into strips with a dimension of 3 × 2 cm 2 . The g/FTO strips were washed using soap water in an ultrasonic bath, alcohol, rinse thoroughly in DI water and dried using nitrogen gas [18]. After the thin-film layer deposition, the 3 × 2 cm 2 strips were cut into two halves of 3 × 1 cm 2 .…”

Section: Thin-film Synthesismentioning

confidence: 99%

“…Coatings 2019, 9, x FOR PEER REVIEW 5 of 15 conduction type is done using photoelectrochemical (PEC) cell measurements by the formation of a junction between the solid (g/FTO/CdTe) and liquid (an aqueous solution of 0.1 M Na2S2O3 in 20 mL DI water). The comprehensive detail of the PEC set up is incorporated in [18].…”

Section: X-ray Diffraction (Xrd) Analysismentioning

confidence: 99%

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Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride

Ojo

Dharmadasa

2019

Coatings

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Electrodeposition of cadmium telluride (CdTe) on fluorine doped tin oxide (FTO) using two electrode configurations was successfully achieved with the main focus on the growth temperature. The electroplating temperatures explored ranged between 55 and 85 • C for aqueous electrolytes containing 1.5 M cadmium nitrate tetrahydrate (Cd(NO 3 ) 2 ·4H 2 O) and 0.002 M tellurium oxide (TeO 2 ). The ensuing CdTe thin-films were characterized using X-ray diffraction (XRD), UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and photoelectrochemical (PEC) cell measurements. The electroplated CdTe thin-films exhibit a dominant (111) CdTe cubic structure, while the crystallite size increases with the increase in the electroplating temperature. The dislocation density and the number of crystallites per unit area decrease with increasing growth temperature. The optical characterization depicts that the CdTe samples show comparable absorbance and a resulting bandgap of 1.51 ± 0.03 eV for as-deposited CdTe layers. A marginal increase in the bandgap and reduction in the absorption edge slope towards lower deposition temperatures were also revealed. The annealed CdTe thin-films showed improvement in the energy bandgap as it tends towards 1.45 eV while retaining the aforementioned absorption edge slope trend. Scanning electron microscopy shows that the underlying FTO layers are well covered with increasing grain size observable relative to the increase in the deposition temperature. The energy dispersive X-ray analyses show an alteration in the Te/Cd relative to the deposition temperature. Higher Te ratio with respect to Cd was revealed at deposition temperature lower than 85 • C. The photoelectrochemical cell study shows that both pand n-type CdTe can be electroplated and that deposition temperatures below 85 • C at 1400 mV results in p-type CdTe layers.Coatings 2019, 9, 370 2 of 15 cadmium telluride (CdTe) thin-films can be grown and incorporated for different applications. CdTe is one of the II-VI semiconductor materials that has been grown using several techniques including electroplating [4,5] and has been extensively researched owing to its properties [6]. Due to the direct bandgap of CdTe at room temperature (~1.45 eV), it is capable of absorbing a substantial fraction of the electromagnetic spectrum under AM1.5 conditions. This characteristic has been explored in the photovoltaic (PV) community in achieving high-efficiency CdTe-based solar cells [7]. The recent hike in the conversion efficiency from 16.5% in 2004 [8] to 22.1% in 2016 [9] as reported in the literature is mainly due to the eradication of defects within the crystal lattice or traps within the bandgap in addition to improved crystallinity, passivation of the grain boundaries which is due to better understanding of both material and device issues. Therefore, it is fundamental to strive towards process optimization amongst others. Under both two and three-electrode electrodeposition configurations, different deposition temp...

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Section: Discussionmentioning

confidence: 99%

Section: Thin-film Synthesismentioning

confidence: 99%

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Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride

Ojo

Dharmadasa

2019

Coatings

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“…Our group has proposed [5,6], and is now working on, next generation multilayer solar cells based on graded bandgap devices [4][5][6][7]. These devices can be built on both n-type and p-type wide bandgap window layers [8].…”

Section: Introductionmentioning

confidence: 99%

Magnesium Incorporation in n-CdTe to Produce Wide Bandgap p-Type CdTe:Mg Window Layers

et al. 2018

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In order to develop wide bandgap p-type window materials to use in graded bandgap devices, the effects of magnesium (Mg) in n-CdTe layers were explored. In this work, magnesium-incorporated cadmium telluride (CdTe:Mg) layers were electroplated using two-electrode method. The layers were deposited on glass/FTO (flourine doped tin oxide) substrates, using an aqueous solution containing Cd2+, Mg2+ and tellurium dioxide (TeO2) as the precursors. X-ray diffraction (XRD) studies indicate the reduction of crystallinity as the Mg concentration is increased in parts per million (ppm) level. Material becomes a completely amorphous layer at high Mg concentrations in the electrolytic bath. Photoelectrochemical (PEC) measurements show the gradual reduction of n-CdTe turning into p-CdTe layers when Mg concentration is increased in the electrolyte. Optical absorption measurements show the expansion of energy bandgap from CdTe bandgap (~1.48 eV) up to ~2.85 eV. The other characterisation results (energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL)) are also explored and presented together with above experimental results.

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“…The cost of the wafer in c-Si PV modules constitutes around 48% of the total price [9] as shown in Table 1, thin film Si based systems use up to 99% less material, and are subsequently cheaper, however the lower efficiency offsets the cost per watt. Promising research into thin film technologies may be found here [32,72]. Electrically conductive layers on glass (indium tin oxide or fluorine doped tin oxide) allows for the growth of thin film semiconductors in a low cost manner such as electrodeposition.…”

Section: Photon Absorbing Layermentioning

confidence: 99%

Effects of d0 and s2 cations on optical properties of silicate glasses

Allsopp¹

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In partial fulfilment of its requirements for The Degree of Doctor of Philosophy 2 Declaration I hereby declare, that the thesis entitled 'Effects of d 0 and s 2 cations on optical properties of silicate glasses' is a result of my original work and investigation. None of the results presented in the manuscript have been lifted from any other sources and legitimate references are presented where necessary. Name:Signature:The copyright of this thesis rests with the author and no quotations from it or information derived from it may be published without prior written consent of the author. 3 Published work and conferences Aspects of the work described in the thesis were published in:• Optical and structural properties of d 0 ion doped silicate glasses for photovoltaic applications. B.

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Next Generation Multilayer Graded Bandgap Solar Cells

Cited by 35 publications

References 0 publications

Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride

Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride

Magnesium Incorporation in n-CdTe to Produce Wide Bandgap p-Type CdTe:Mg Window Layers

Effects of d0 and s2 cations on optical properties of silicate glasses

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