A Novel Approach for Designing a Sub-Bandgap in CuGa(S,Te)₂ Thin Films Assisted with Numerical Simulation of Solar Cell Devices for Photovoltaic Application

Abstract

As a well-explored chalcopyrite material, copper gallium sulfide CGS has been considered a potential material for solar cell absorber layers. However, its photovoltaic attributes still require to be improved. In this research, a novel chalcopyrite material, copper gallium sulfide telluride CGST, has been deposited and verified as a thin film absorber layer to fabricate high-efficiency solar cells by experimental testing and numerical simulations. The results display the intermediate band formation in CGST with incorporation of Fe ions. Electrical studies showed enhancement in mobility from 1.181 to 1.473 cm2 V–1 s–1 and conductivity from 2.182 to 5.952 S cm–1 for pure and 0.08 Fe-substituted thin films. The I–V curves display the photoresponse and ohmic nature of the deposited thin films, and the maximum photoresponsivity (0.109 A W–1) was observed for 0.08 Fe-substituted films. Theoretical simulation of the prepared solar cells was carried out using SCAPS-1D software, and the obtained efficiency displayed an increasing trend from 6.14 to 11.07% as the Fe concentration increased from 0.0 to 0.08. This variation in efficiency is attributed to the decrease in bandgap (2.51–1.94 eV) and the formation of an intermediate band in CGST with Fe substitution, which is evidenced in UV–vis spectroscopy. The above revealed results open the way to 0.08 Fe-substituted CGST as a promising candidate as a thin film absorber layer in solar photovoltaic technology.

Development of Sub‐Band in Spray‐Deposited Cr‐Substituted Chalcopyrite Thin Films for Advancing Solar Cell Efficiency

“…Parameters for the simulation of CG 1Àx Cr x ST/In 2 S 3 /AZO heterojunction solar cells structures. [41,42,73,74] Layer parameters CG 1Àx Cr x ST [3] In 2 S 3 [43] AZO [73] Thickness of the layer 1.…”

“…The presence of the sub-bandgap associated with Cr-substituted CGST films may result in an enhanced current generation at the voltage corresponding to the energy gap value, as explained in the simulation section. [3,19,51,52] The determination of the optical bandgap for the thin films involves extrapolating the linear segment of the graph to the photon energy (hν) axis, using Tauc's equation. [5] As depicted in Figure 3, the application of Tauc's method reveals that the bandgap for the pure CGST film equals 2.40 eV.…”

“…On the other hand, conventional thin filmbased solar cells using chalcopyrite Cu(In, Ga)Se 2 and CdTe have demonstrated exceptional efficiency, surpassing 23.6% and 21%, respectively, due to their high absorption coefficient. [3] Additionally Cu(In,Ga)Se 2 -based solar cells exhibit superior stability and reproducibility compared to organic and hybrid counterparts. However, the scarcity and high cost of the constituent elements (In, Ga, and Te) in the Earth's shell hinder the widespread adoption of Cu(In,Ga)Se 2 and CZT(S,Se) 2 as absorber layers.…”

“…It exhibits p-type conductivity and possesses a direct bandgap of 2.4 eV, creating IB among chalcopyrite semiconductors. [1,3,[19][20][21][22] However, the bandgap plays a crucial role in determining the absorption characteristics of a solar cell. To modify the bandgap of CuGa(S,Te) 2 , it can be doped with various transition elements.…”

Hierarchically structured sub-bands in chalcopyrite thin-film solar cell devices

“…The CG 1Àx V x ST is a promising p-type semiconductor with an optical bandgap of about 2.63 eV and with the resulting high absorption coefficient in the range of 10 5 cm À1 . 32 3.2 Buffer layer (In 2 S 3 )…”