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Enhancing the opto-electronic performance of Cadmium Telluride TFSC 1

3^rd INTERNATIONAL CONFERENCE ON

ELECTRICAL, COMPUTER & COMMUNICATION ENGINEERING

23-25 FEBRUARY 2023, CUET, Chittagong, Bangladesh

The Use of Plasmonic Metal Nanoparticles to Enhance The Opto-electronic Performance of Thin- Film/Ultrathin Film CdTe Solar Cells

Asif Al Suny, Rifat Bin Sultan, Samina Tohfa, Abrar Jawad Haque,

Dr. Mustafa Habib Chowdhury

IUB Photonics Simulation Laboratory

Department of Electrical & Electronic Engineering

INDEPENDENT UNIVERSITY, BANGLADESH

Paper ID: 387

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Problem Statement
Literature Review
Feasibility of CdTe
Research Methodology
Simulation Setup
Results & Discussion
Manufacturing Feasibility
Conclusion

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TABLE of CONTENTS

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PROBLEM STATEMENT

Efficiency of thin-film solar cells (TFSCs) is relatively low, approximately 7-15%. [1]
This is even lower than the crystalline solar cells (above 18-25%). [2]
No detailed analysis of temperature variation effect from heating on plasmonic CdTe TFSC.
The efficiency needs to be significantly enhanced if we are to integrate thin-film/ultrathin CdTe solar cell in portable electric devices and other applications

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Potential Use of Thin/Ultrathin Film Solar Cell

Smart Watch

Transparent Window

Thermal Jacket

Smart Phone

At 300K (room temperature) and visible range, the absorption coefficient of Cd-Te material is around 10⁶ (cm^-1) whereas for amorphous silicon, it is 10⁵(cm^-1). Although many electronic gadgets which rely on thin film solar cells currently use a-Si for large scale production, CdTe can play a pioneering role to bring down the large-scale requirement of semi-conductor materials as it can absorb more for given thickness of material compared to amorphous silicon.

Solar Powered Car

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RESEARCH SCOPE

To study the feasibility of using plasmonic metal nanoparticles for performance enhancement along with temperature variation study on ‘plasmonic’ CdTe-TFSCs and its miniaturization for application on modern electronic devices.

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Why CdTe TFSC?

CdTe is more preferable due to its high absorption coefficient factor, low carbon footprint and production cost.

Unlike Si, which is an indirect band gap material, CdTe is a direct band gap material.

Therefore, the required absorbing layer thickness for efficient light absorption is significantly low (300-350 times tinner) compared to other commercially available TFSCs. [4]

Cadmium (Cd) is found abundantly as a by-product of the zinc mining industry and thus Cd is relatively less prone to price fluctuations unlike Si.

Currently, CdTe based solar cells have the major market share of the TFSC market compared to Si based solar cells. [Fraunhofer ISE]

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SURFACE PLASMON RESONANCE

The scattering of light by certain metallic nanoparticles/nanostructures creates high electromagnetic (EM) fields .
This phenomenon occurs due to the collective oscillation of the surface electrons in the in the metal nanoparticles (surface plasmon resonance).

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RESEARCH METHODOLOGY

Commercially available Finite-Difference Time-Domain (FDTD) simulation tools designed by Ansys Lumerical Inc.

FDTD Solution solver was used, which utilizes the FDTD method, to perform the calculations for the optical enhancement analysis.

CHARGE solver was used for the electrical analysis.

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RESEARCH METHODOLOGY

Absorption Enhancement

Factor

Optical Nearfield

Short-Circuit Current Density

Open Circuit Voltage

Fill Factor

Optical Analysis

Electrical Analysis

Output

power

and

Efficiency

Conclusion (optimal) for each configuration

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OPTICAL SIMULATION SETUP

Fig. FDTD Simulation setup for optical analysis, using top and bottom monitors.

Simulation Software: FDTD Solutions and CHARGE by Ansys Lumerical
Temperature: 300K
Boundary Condition: PML
Source: Plain wave (STC)
Solar Spectral Irradiance: 1000Wm^-2(STC)
Air Mass: AM1.5G (STC)
Wavelength range= 400-1100 nm with 150 frequency points
Mesh type: Conformal Mesh
Mesh size: 5nm

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ELECTRICAL SIMULATION SETUP

Fig. CHARGE Simulation setup for electrical analysis.

P-Type Doping Concentration: 1x10¹⁶ cm^-3
N-Type Doping Concentration: 1x10¹⁵cm^-3
Voltage Sweeping Range: 0-1.13V (18 Points)
Temperature dependence: Isothermal

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A. Optical Absorption Enhancement factor

RESULTS AND DISCUSSION

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[5]

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B. Short Circuit Current Density (J_SC)

C. Open Circuit Voltage (V_OC)

RESULTS AND DISCUSSION

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D. Fill Factor (FF)

E. Efficiency (ƞ)

RESULTS AND DISCUSSION

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Cities Chosen for Temperature Study

Efficiency (ƞ) & J_SC vs Temperature (K)

RESULTS AND DISCUSSION

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Analysis Between Ultrathin Plasmonic CdTe and Si SC

Substrate & NP	thickness	Jsc (mA/cm^2)	Voc (V)	FF	Pout (mW/cm^2)	Efficiency	Comment
CdTe with 100 nm Ag NP	200 nm	24.29	0.5966	0.4950	7.17	7.17%	CdTe is 21 times more efficient than Si
Si with 100 nm Ag NP	200 nm	4.00	0.5940	0.1450	0.34	0.34%	CdTe is 21 times more efficient than Si
CdTe with 200 nm Ag NP	1600 nm	34.26	0.7012	0.5279	12.68	12.68%	CdTe is 1.78 times more efficient than Si
Si with 200 nm Ag NP	1600 nm	18.91	0.6953	0.5409	7.11	7.11%	CdTe is 1.78 times more efficient than Si

RESULTS AND DISCUSSION

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RESULTS AND DISCUSSION

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Optical Near-Field Enhancement

For Wavelength of 400-1100 nm

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MANUFACTURING FEASIBILITY

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Many studies revealed contemporary fabrication techniques, such as close-spaced sublimation (CSS), wet chemical approach etc.

There are several methods of depositing spherical nanoparticles on substrates, for example, uniform NPs in aerosol form, colloidal dispersions via electrospray deposition, evaporation or sputtering, etc. [6]

Since the proposed design of this study requires the deposition of plasmonic metal nanoparticles on CdTe substrate, one way such deposition can take place would by nanoparticle droplets spread onto the TFSC substrate using capillary forces.

Credit: PowerFilm Solar

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CONCLUSION

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The aim of this systematic computational study was to enhance the performance of CdTe “plasmonic “thin-film/ultrathin film solar cells (TFSCs) with plasmonic metal nanoparticle configurations and study temperature dependency on performance parameters.

Efficiency of CdTe TFSC is poor compared to crystalline Silicon due to its reduced thickness of absorber layer.

One way of achieving greater absorption is via strong plasmonic coupling of the incident light with the plasmonic metal nanoparticles due to the substantial size of the area under the extinction curve of the plasmonic nanoparticles in the wavelength range of 400-1100 nm.

The calculated results showed CdTe TFSCs modified with 200 nm diameter Ag NP shows the highest efficiency compared to its Silicon counterpart. CdTe is also robust against temperature variation.

The limitations of this study include lack of experimental verification of the simulation results. Such experimental verification would involve the complex fabrication process of plasmonic metal NPs with controlled shapes and sizes and incorporation to the CdTe TFSC.

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FUTURE WORK

Future works will be focused on designing highly efficient CdTe TFSCs incorporating other light trapping techniques

Nanograting & Surface texturing
Varying the shapes of plasmonic nanoparticles.
Adding shell layers of different materials like graphene or silica on the nanoparticles and gratings).
Perform a comparative study with Si and other absorbing materials commonly used in TFSCs.

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REFERENCES

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[1] David, L. et al. (2023) Thin-Film Solar Panels (2023 guide), EcoWatch. Available at: https://www.ecowatch.com/solar/thin-film-solar-panels.

[2] Moon, Md. Mahabub Alam & Rahman, Md & Hossain, Jaker & Ismail, Abu Bakar Md. (2019). Comparative Study of the Second-Generation a-Si:H, CdTe, and CIGS Thin-Film Solar Cells. Advanced Materials Research. 1154. 102-111. 10.4028/www.scientific.net/AMR.1154.102.

[3] R. A. Rifat, N. Ibn Ashraf, S. A. Chowdhury, and M. H. Chowdhury, “The use of plasmonic metal nanoparticles to enhance the efficiency of thin-film silicon (SI) and gallium arsenide (GaAs) Solar Cells – A comparative study,” 2018 International Conference and Utility Exhibition on Green Energy for Sustainable Development (ICUE), 2018.

[4] Thin-film solar panels, American Solar Energy Society. Available at: https://ases.org/thin-film-solar-panels.

[5] Sakai T., Enomoto H., Sakai H., and Abe M., 2014. Hydrogen-assisted fabrication of spherical gold nanoparticles through sonochemical reduction of tetrachloride gold(III) ions in water. Ultrasonics Sonochemistry 21 (3): 946-950. H

[6]“Absorption coefficient,” PVEducation. [Online]. Available at: https://www.pveducation.org/pvcdrom/pn-junctions/absorption-coefficient. ��

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Co-Authors

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MUSTAFA H. CHOWDHURY

Associate professor,

Department of EEE, IUB

Director, IUBPSL

Senior Member, IEEE

ABRAR JAWAD HAQUE

Research Assistant,

Department of EEE, IUB

IUBPSL

(2020-2022)

RIFAT BIN SULTAN

Undergraduate Student,

Department of EEE, IUB

IUBPSL

(2022-Present)

SAMINA TOHFA

Undergraduate Student,

Department of EEE, IUB

IUBPSL

(2022-Present)

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ACKNOLEDGEMENT

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The authors would like to acknowledge Independent University, Bangladesh (IUB) for funding this research (Research Project No: 2021-SETS-08) and providing other logistical support.

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QUESTIONS?

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IUB-PSL