With rising energy demand and depleted traditional fuels, solar cells offer a sustainable and clean option. In recent years, and due to its acceptable band gap, high absorption coefficient, and inexpensive cost, iron pyrite (FeS₂) is a popular material for solar cells. Earth abundance and nontoxicity further boost its photovoltaic possibilities. The current study examined the influence of sulfurization at 350–400 °C on iron pyrite layers fabricated using spray pyrolysis. The morphology and size from TEM confirmed the XRD results of synthesizing a pyrite FeS₂ with an average particle size of 10–23 nm at 350–400 °C, respectively. The direct band gap calculated by DFT as a function of temperature was found to be consistent with the experimental findings, 0.87 eV (0.87) and 0.90 eV (0.95) at 350 °C and 400 °C, respectively. We found high-performing photovoltaic cells on ITO/ZnO/FeS₂/ MoO₃/Au/Ag, obtained with an excellent quality of nanoparticles and nanostructures of FeS₂ pyrite, which improved with the method of preparation and growth parameters.

F e S 2 pyrite is one of the most interesting photovoltaic materials with low-cost and natural abundance but with small band gap of 0.95 eV. In the present work, we show the feasibility of increases band gap was determined by Zinc alloying of Iron pyrite. We showed that we can increase the band gap of F e S 2 pyrite to 1.15 e V by theoretical calculation and to 1.16 e V using experimental method, by just adding a very small amount of Zinc ( 1 % ) . We prepared our samples by chemical vapor transport technic and we utilized the technic of linear muffin-tin orbital method in the atomic-sphere approximation (LMTO-ASA). The effect of Zinc alloyed Iron pyrite were examined by transmission electron micrograph TEM, XRD, Raman spectroscopy and optical characterization.

Pyrite ${\mathrm{FeS}}_2$ has become the focus of many researchers in thin-film photovoltaics because it has some possibilities in photovoltaics. In this manuscript, we present an experimental and a theoretical study of the electronic structure of pyrite ${\mathrm{FeS}}_2$ alloyed with a small concentration of 1.19% of ruthenium (${\mathrm{Fe}}_{0.9881}{\mathrm{Ru}}_{0.0119}{\mathrm{S}}_2$) by using the Linear Muffin-Tin Orbital Method in the Atomic-Sphere approximation (LMTO-ASA) calculations and the density of states. We observed that the bandgap of ${\mathrm{FeS}}_2$ increases from $0.90508$ to $1.21586 \mathrm{eV}$ when we replace $~1.19\%$ of the $\mathrm{Fe}$ atoms with ruthenium atoms $\left(\mathrm{x}=0.0119 \mathrm{concentration} \mathrm{of} \mathrm{Ru}\right)$. We prove that this low concentration of Ru saved the gap states and the electronic and optical properties of ${\mathrm{FeS}}_2$ pyrite. Our calculated electronic bandgap is $1.21586 \mathrm{eV}$ and direct. Our results confirm that the symmetric operation of the space ${\mathrm{T}}_{\mathrm{h}}^6 \left(\mathrm{Pa}3\right)$ saves electronic structure of iron pyrite when alloyed with ruthenium.

In this manuscript, we study the grouping of bands and optical properties of p-type Zn S 2 pyrite, which helps us in the study of crystal p-type Zn S 2 pyrite and its impact in organic photovoltaic cells. Our work has two approaches one theorical where we find the band structure of p − type Zn S 2 by using linear muffin-tin orbital method in the atomic-sphere approximation (LMTO-ASA), the second approach is the experimental where we prepare the crystals by chemical vapor transport. The sample was examined by XRD and optical characterizations. Our results show that the p-type Zn S 2 pyrite is a direct semiconductor with optical gap about 1.610 eV and calculated gap about 1.550 eV . As an illustration of our finding, we present an application of our work to photovoltaic devices.

In pursuit of augmenting the band gap value of thin films composed of $Fe{S}_2$ Pyrite, our study encompasses both theoretical and experimental investigations. Specifically, we sought to delve into the electronic and optical properties of $Fe{S}_2$ alloyed with ruthenium, denoted as $F{e}_{1-x}R{u}_x{S}_2$, where x varied across a range of values (x = 0.3966, 0.1586, 0.0496, 0.0347, 0.0106, and 0.00). Our theoretical analysis employed the Linear Muffin-Tin Orbital technique within the Atomic-Sphere approximation (LMTO-ASA) framework, focusing on the density of states. In parallel, our experimental samples were fabricated via a cost-effective and straightforward method involving the sulfuration of amorphous iron oxide thin films, which were deposited through spray pyrolysis of an aqueous solution containing FeCl3.6H2O onto heated glass substrates at 400 °C. This comprehensive investigation sheds light on the influence of alloying on the atomic structure and the optical characteristics of $R{u}_{x}F{e}_{1-x}{S}_2$ samples. Utilizing X-ray diffraction (XRD) and optical characterizations, we observed a notable widening of the band gap of $Fe{S}_2$, ranging from 0.90508 to 1.38 eV, when approximately 1.06% of the Fe atoms were replaced with ruthenium atoms (x = 0.0106 concentration of Ru). This finding holds significant implications for the potential applications of our samples in photovoltaic technologies.