Efficiency of Thin-Film CdS/CdTe Solar Cells

Kosyachenko, L. A.

doi:10.5772/8065

Cited by 15 publications

(22 citation statements)

References 30 publications

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“…For un-annealed cell, the quantum efficiency is very low for lower wavelengths and increases very sharply at the wavelength near the band gap energy of CdTe. The triangular/ rectangular nature of the EQE for the un-annealed/annealed cell is due to the low/high density of uncompensated acceptor concentrations (N a -N d ) [11]. The initial increase in EQE around the band gap wavelength of the un-annealed cell is due to the efficient photo-generated carriers from the bulk of the film caused by the expansion of the depletion layer.…”

Section: Cdte/cds Cell Testingmentioning

confidence: 98%

“…While closed space sublimation has been a predominant way of getting cadmium telluride thin films [3], other methods like vacuum evaporation [4], electrodeposition [5] and sputtering [6] have been used. An efficiency of 11.6% has been reported in a CdTe/CdS solar cell in which both layers were grown by planar magnetron radio frequency sputtering [6]. The improved efficiency was attributed to the improved minority carrier life-time in the films grown by unbalanced magnetron.…”

Section: Introductionmentioning

confidence: 96%

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CdTe Solar Cell from Sputtering Method

et al. 2012

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We report CdTe/CdS solar cell with CdTe layer grown by sputtering method. A controlled etch and anneal process on the sputter-grown CdTe films was performed to increase the average grain size of the film. The process involved dipping the CdTe films in a saturated solution of cadmium chloride (CdCl 2 ) in methanol (2.08 gram in 100 ml) followed by a 30 minute annealing at 400 °C. We performed various experiments on this process by varying the dipping times, drying process and annealing times and analyzed the resultant films using Scanning Electron Microscopy (SEM). We could see a clear increase in grain size from 200 nm to 5 µm after CdCl 2 treatment. The process also increased the overall roughness of the sample so that more light is absorbed than reflected. We prepared solar cells using CdTe as p-type layer and CdS as n-type layer. The efficiency of the cell improved from 1.1% to 4.2% after air annealing. The effect of air-annealing is studied by means of quantum efficiency measurement.

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Section: Cdte/cds Cell Testingmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 96%

CdTe Solar Cell from Sputtering Method

et al. 2012

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“…The photocurrent density limited by ambipolar diffusion at the quasi-neutral regions are given by Kosyachenko (2010) and Nelson (2003):…”

Section: I-v Modelingmentioning

confidence: 99%

Design of thin film solar cells based on a unified simple analytical model

Acevedo-Luna

Bernal-Correa

Montes-Monsalve

et al. 2017

Journal of Applied Research and Technology

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Polycrystalline thin film solar cells made with absorber materials such as CdTe, CIGS, CZTS and metalorganic halides (perovskites) are currently important alternatives for the silicon solar cell technology, which still dominates the photovoltaic market. Then, it is important to have tools which can be used to design this kind of solar cells. For this purpose, we have developed a unified simple analytical model that can be applied to thin film solar cells. The model is based on the basic physics of hetero-junction devices, but it takes into consideration that the space charge region can extend along the major part of the cell length, particularly for very thin cells, causing important effects that typically are not observed in conventional junction devices. Photo-generated carriers are collected by electric field-drift instead of diffusion, and simultaneously strong recombination at this region may dominate the electrical I-V characteristic of the cell. Since the space-charge region width varies with the applied voltage, the illumination current density and the saturation dark current density are no longer independent of the voltage as is assumed for conventional solar cells. When the model is applied to CIS and CdTe solar cells as examples, it is found that it is possible to design very thin film solar cells (absorber less than 1 m thick) with high efficiencies, whenever the recombination velocity at the back surface becomes small (10 2 cm/s), instead of the high recombination velocities present at ohmic contacts (10 7 cm/s). This fact implies the cost reduction of thin film solar cells by reducing absorber material thickness, and therefore it poses a challenge to develop deposition methods for very thin CdTe and CIGS absorber materials without pinholes, so that improved efficiencies are obtained when the surface recombination velocity is made small at the back by having a p+ or an electron blocking region before the ohmic contact. This result also explains the high efficiencies achieved by very thin perovskite solar cells.

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“…Few samples of CdTe thin film were prepared by thermal evaporation and deposited on glass substrate to be examined individually. A comprehensive study of CdTe layer in CdS/CdTe solar cell had been conducted [21], and the main parameters of CdTe material that affect the module efficiency had been discussed. Among these parameters are the lifetime, diffusion length, drift length of minority carriers and thickness of CdTe absorber layer.…”

Section: Laboratory Preparations and Solar Cell Structurementioning

confidence: 99%

Power Conversion Enhancement of CdS/CdTe Solar Cell Interconnected with Tunnel Diode

Mohammed¹,

Daoud²,

Al-Tikriti³

2012

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One of the most promising solar cell devices is cadmium telluride (CdTe) based. These cells however, have their own problems of stability and degradation in efficiency. Measurements show that CdS/CdTe solar cell has high series resistance which degrades the performance of solar cell energy conversion. Both active layers (CdS and CdTe) had been fabricated by thermal evaporation and tested individually. It was found that CdS window layer of 300 nm have the lowest series resistance with maximum light absorption. While 5 - 7 µm CdTe absorber layer absorbed more than 90% of the incident light with minimum series resistance. A complete CdS/CdTe solar cell was fabricated and tested. It was found that deposited cell without heat treatment shows that the short circuit current increment decreases as the light intensity increases. This type of deposited cell has low conversion efficiency. The energy conversion efficiency was improved by heat treatment, depositing heavily doped layer at the back of the cell and minimizing the contact resistivity by depositing material with resistivity less than 1 m??cm<sup>2</sup>. All these modifications were not enough because the back contact is non-ohmic. Tunnel diode of CdTe (p++)/CdS (n++) was deposited in the back of the cell. The energy conversion efficiency was improved by more than 7%

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Efficiency of Thin-Film CdS/CdTe Solar Cells

Cited by 15 publications

References 30 publications

CdTe Solar Cell from Sputtering Method

CdTe Solar Cell from Sputtering Method

Design of thin film solar cells based on a unified simple analytical model

Power Conversion Enhancement of CdS/CdTe Solar Cell Interconnected with Tunnel Diode

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