WS₂: A New Window Layer Material for Solar Cell Application.

Area of Science:

• Materials Science
• Thin Film Technology
• Renewable Energy

Background:

• Thin-film solar cells require advanced window layer materials for improved performance.
• Tungsten disulfide (WS2) is a promising material with suitable optoelectronic properties for solar applications.

Purpose of the Study:

• To optimize the deposition of WS2 thin films using radio frequency (RF) magnetron sputtering.
• To investigate the impact of RF power on the structural, morphological, and optoelectronic properties of WS2 films.
• To evaluate the performance of WS2 as a window layer in Cadmium Telluride (CdTe) solar cells.

Main Methods:

• Radio frequency (RF) magnetron sputtering was employed to deposit WS2 thin films on soda lime glass.
• Deposition power was varied (50-250 W) to study its effect on film characteristics.
• Characterization included analysis of morphological, structural, and optoelectronic properties.
• Fabrication and testing of CdTe/WS2 solar cells were performed.

Main Results:

• Optimized WS2 films were achieved at an RF deposition power of 200 W, exhibiting a bandgap of 2.2 eV, carrier concentration of 1.01 × 10^19 cm^-3, and resistivity of 0.135 Ω-cm.
• The WS2 films displayed a granular morphology and a rhombohedral phase with preferential (101) orientation.
• The first-time incorporation of WS2 as a window layer in a CdTe solar cell resulted in a photovoltaic conversion efficiency of 1.2%.

Conclusions:

• RF magnetron sputtering is an effective method for depositing high-quality WS2 thin films for solar cell applications.
• Optimized WS2 films possess suitable properties to function as a window layer in thin-film solar cells.
• This research highlights the potential of WS2 as a viable alternative window layer material for enhancing solar cell technology.