Transparent conducting materials are key elements in a wide variety of current technologies including flat panel displays, photovoltaics, organic, low-e windows and electrochromics. The needs for new ...and improved materials is pressing, because the existing materials do not have the performance levels to meet the ever- increasing demand, and because some of the current materials used may not be viable in the future. In addition, the field of transparent conductors has gone through dramatic changes in the last 5-7 years with new materials being identified, new applications and new people in the field. 'Handbook of Transparent Conductors' presents transparent conductors in a historical perspective, provides current applications as well as insights into the future of the devices. It is a comprehensive reference, and represents the most current resource on the subject.
Full text
Available for:
FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We show in this article that the position of semiconductor band edges relative to the water reduction and oxidation levels can be reliably predicted from the ionization potentials (IP) and electron ...affinities (AE) only. Using a set of 17 materials, including transition metal compounds, we show that accurate surface dependent IPs and EAs of semiconductors can be computed by combining density functional theory and many-body GW calculations. From the extensive comparison of calculated IPs and EAs with available experimental data, both from photoemission and electrochemical measurements, we show that it is possible to sort candidate materials solely from IPs and EAs thereby eliminating explicit treatment of semiconductor/water interfaces. We find that at pH values corresponding to the point of zero charge there is on average a 0.5 eV shift of IPs and EAs closer to the vacuum due to the dipoles formed at material/water interfaces.
Defect tolerance is the tendency of a semiconductor to keep its properties despite the presence of crystallographic defects. Scientific understanding of the origin of defect tolerance is currently ...missing. Here we show that semiconductors with antibonding states at the top of the valence band are likely to be tolerant to defects. Theoretical calculations demonstrate that Cu3N with antibonding valence band maximum has shallow intrinsic defects and no surface states, in contrast to GaN with bonding valence band maximum. Experimental measurements indicate shallow native donors and acceptors in Cu3N thin films, leading to 1016–1017 cm–3 doping with either electrons or holes depending on the growth conditions. The experimentally measured bipolar doping and the solar-matched optical absorption onset (1.4 eV) make Cu3N a promising candidate absorber for photovoltaic and photoelectrochemical solar cells, despite the calculated indirect fundamental band gap (1.0 eV). These conclusions can be extended to other materials with antibonding character of the valence band, defining a class of defect-tolerant semiconductors for solar energy conversion applications.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
This critical review focuses on the solution deposition of transparent conductors with a particular focus on transparent conducting oxide (TCO) thin-films. TCOs play a critical role in many current ...and emerging opto-electronic devices due to their unique combination of electronic conductivity and transparency in the visible region of the spectrum. Atmospheric-pressure solution processing is an attractive alternative to conventional vacuum-based deposition methods due to its ease of fabrication, scalability, and potential to lower device manufacturing costs. An introduction into the applications of and material criteria for TCOs will be presented first, followed by a discussion of solution routes to these systems. Recent studies in the field will be reviewed according to their materials system. Finally, the challenges and opportunities for further enabling research will be discussed in terms of emerging oxide systems and non-oxide based transparent conductors (341 references).
The emergence of methyl-ammonium lead halide (MAPbX3) perovskites motivates the identification of unique properties giving rise to exceptional bulk transport properties, and identifying future ...materials with similar properties. Here, we propose that this “defect tolerance” emerges from fundamental electronic-structure properties, including the orbital character of the conduction and valence band extrema, the charge-carrier effective masses, and the static dielectric constant. We use MaterialsProject.org searches and detailed electronic-structure calculations to demonstrate these properties in other materials than MAPbX3. This framework of materials discovery may be applied more broadly, to accelerate discovery of new semiconductors based on emerging understanding of recent successes.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A look at how solution processing can help reduce the cost of inorganic solar cell technologies is presented. The article also examines the development of inorganic solution precursors and deposition ...tehccniques.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
The influence of protonation reactions between poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and a thiadiazolo3,4‐cpyridine small‐molecule donor are reported; these result in ...poor solar‐cell performance due to a barrier for charge extraction. The use of a NiOx contact eliminates such deleterious chemical interactions and results in substantial improvements in open‐circuit voltage, fill factor, and an increased power conversion efficiency from 2.3% to 5.1%.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
As the world’s demand for energy grows, the search for cost competitive and earth abundant thin film photovoltaic absorbers is becoming increasingly important. A promising approach to tackle this ...challenge is through thin film photovoltaics made of elements that are abundant in the Earth’s crust. In this work, we focus on Cu2SnS3, a promising earth abundant absorber material. Recent publications have presented 3% and 6% device efficiencies using Cu2SnS3-based absorber materials and alloys, respectively. However, little is understood about the fundamental defect and doping physics of this material, which is needed for further improvements in device performance. Here, we identify the origins of the changes in doping in sputtered cubic Cu2SnS3 thin films using combinatorial experiments and first-principles theory. Experimentally, we find that the cubic Cu2SnS3 has a large phase width and that the electrical conductivity increases with increasing Cu and S content in the films, which cannot be fully explained by the theoretical point defect model. Instead, theoretical calcuations suggest that under Cu-rich conditions alloying with an isostructural metallic Cu3SnS4 phase occurs, causing high levels of p-type doping; this theory is consistent with experimental Raman and NEXAFS spectroscopy data. These experimental and theoretical works lead to the conclusion that Cu2SnS3 films must be grown both S-poor and Cu-poor in order to achieve moderate hole concentrations. These new insights enable the design of growth processes that target the desired carrier concentrations for solar cell fabrication. Using the strategies described above, we have been able to tune the carrier concentration over >3 orders of magnitude and achieve films with p-type doping of ≤1018 cm–3, facilitating future device integration of these films.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Hydrothermal synthesis is challenging in metal oxide systems with diverse polymorphism, as reaction products are often sensitive to subtle variations in synthesis parameters. This sensitivity is ...rooted in the non-equilibrium nature of low-temperature crystallization, where competition between different metastable phases can lead to complex multistage crystallization pathways. Here, we propose an ab initio framework to predict how particle size and solution composition influence polymorph stability during nucleation and growth. We validate this framework using in situ X-ray scattering, by monitoring how the hydrothermal synthesis of MnO
proceeds through different crystallization pathways under varying solution potassium ion concentrations (K
= 0, 0.2, and 0.33 M). We find that our computed size-dependent phase diagrams qualitatively capture which metastable polymorphs appear, the order of their appearance, and their relative lifetimes. Our combined computational and experimental approach offers a rational and systematic paradigm for the aqueous synthesis of target metal oxides.
Discovery of new materials is important for all fields of chemistry. Yet, existing compilations of all known ternary inorganic solids still miss many possible combinations. Here, we present an ...example of accelerated discovery of the missing materials using the inverse design approach, which couples predictive first-principles theoretical calculations with combinatorial and traditional experimental synthesis and characterization. The compounds in focus belong to the equiatomic (1:1:1) ABX family of ternary materials with 18 valence electrons per formula unit. Of the 45 possible V–IX–IV compounds, 29 are missing. Theoretical screening of their thermodynamic stability revealed eight new stable 1:1:1 compounds, including TaCoSn. Experimental synthesis of TaCoSn, the first ternary in the Ta–Co–Sn system, confirmed its predicted zincblende-derived crystal structure. These results demonstrate how discovery of new materials can be accelerated by the combination of high-throughput theoretical and experimental methods. Despite being made of three metallic elements, TaCoSn is predicted and explained to be a semiconductor. The band gap of this material is difficult to measure experimentally, probably due to a high concentration of interstitial cobalt defects.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
PDF
