Impact of alloying iron pyrite by ruthenium on its band gap values and its insight to photovoltaic performance

In pursuit of augmenting the band gap value of thin films composed of F e S 2 Pyrite, our study encompasses both theoretical and experimental investigations. Specifically, we sought to delve into the electronic and optical properties of F e 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 F e 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.

Energy supplies and future engines for land, sea, and air

The 2012 Critical Review Discussion complements Wilson, (2012), provides pointers to more detailed treatments of different topics and adds additional dimensions to the area of "energy". These include broader aspects of technologies driven by fuel resources and environmental issues, the concept of energy technology innovation, evolution in transportation resources, and complexities of energy policies addressing carbon taxes or carbon trading. National and global energy data bases are identified and evaluated and conversion factors are given to allow their comparability.

Interface engineering: Boosting the energy conversion efficiencies for nanostructured solar cells

Nanostructured solar cells have attracted increasing attention in recent years because their low cost and ease of preparation offer unique advantages and opportunities unavailable with conventional single-crystalline solar cells. The efficiencies of this kind of solar cell largely depend on the interfacial structure owing to the large specific interface areas and the inherent high density of interface states. In this review article, strategies of interface engineering will be introduced in detail. The up-to-date progress and understanding of interface engineering and its role in influencing the efficiency of nanostructured solar cells will be discussed. Some of the representative examples of the interface engineering method will be presented wherever necessary. Continued boosting of the energy conversion efficiency for nanostructured solar cells is anticipated in the coming years and will bring this kind of solar cell to the status of commercialization.

Consequences of anode interfacial layer deletion. HCl-treated ITO in P3HT:PCBM-based bulk-heterojunction organic photovoltaic devices

In studies to simplify the fabrication of bulk-heterojunction organic photovoltaic (OPV) devices, it was found that when glass/tin-doped indium oxide (ITO) substrates are treated with dilute aqueous HCl solutions, followed by UV ozone (UVO), and then used to fabricate devices of the structure glass/ITO/P3HT:PCBM/LiF/Al, device performance is greatly enhanced. Light-to-power conversion efficiency (Eff) increases from 2.4% for control devices in which the ITO surface is treated only with UVO to 3.8% with the HCl + UVO treatment--effectively matching the performance of an identical device having a PEDOT:PSS anode interfacial layer. The enhancement originates from increases in V(OC) from 463 to 554 mV and FF from 49% to 66%. The modified-ITO device also exhibits a 4x enhancement in thermal stability versus an identical device containing a PEDOT:PSS anode interfacial layer. To understand the origins of these effects, the ITO surface is analyzed as a function of treatment by ultraviolet photoelectron spectroscopy work function measurements, X-ray photoelectron spectroscopic composition analysis, and atomic force microscopic topography and conductivity imaging. Additionally, a diode-based device model is employed to further understand the effects of ITO surface treatment on device performance.