Indium tin oxide

About: Indium tin oxide is a research topic. Over the lifetime, 17857 publications have been published within this topic receiving 402127 citations. The topic is also known as: indium tin oxide.

Photoluminescence of monovalent indium centres in phosphate glass

Abstract: Valence control of polyvalent cations is important for functionalization of various kinds of materials. Indium oxides have been used in various applications, such as indium tin oxide in transparent electrical conduction films. However, although metastable In+ (5 s2 configuration) species exhibit photoluminescence (PL), they have attracted little attention. Valence control of In+ cations in these materials will be important for further functionalization. Here, we describe In+ species using PL and X-ray absorption fine structure (XAFS) analysis. Three absorption bands in the UV region are attributed to the In+ centre: two weak forbidden bands (1S0 → 3P1, 1S0 → 3P2) and a strong allowed band (1S0 → 1P1). The strongest PL excitation band cannot be attributed to the conventional allowed transition to the singlet excited state. Emission decay of the order of microseconds suggests that radiative relaxation occurs from the triplet excitation state. The XAFS analysis suggests that these In+ species have shorter In–O distances with lower coordination numbers than in In2O3. These results clearly demonstrate that In+ exists in a metastable amorphous network, which is the origin of the observed luminescent properties.

Enhanced fluorescence by surface plasmon coupling of Au nanoparticles in an organic electroluminescence diode

Abstract: A significant increase in electroluminescence was achieved through coupling with localized surface plasmons in a single layer of Au nanoparticles. We fabricated a thin-film organic electroluminescence diode, which consists of an indium tin oxide (ITO) anode, a Au nanoparticle array, a Cu phthalocyanine hole transport layer, a tris(8-hydroxylquinolianato) aluminum (III) electron transport layer, a LiF electron injection layer, and an Al cathode. The device structure, with size-controlled Au particles embedded on ITO, can be used to realize the optimum distance for exciton-plasmon interactions by simply adjusting the thickness of the hole transport layer. We observed a 20-fold increase in the molecular fluorescence compared with that of a conventional diode structure.

Thermal Stabilisation of Polymer–Fullerene Bulk Heterojunction Morphology for Efficient Photovoltaic Solar Cells

Abstract: level, and operational stability. [ 3 ] Most of BHJ photoactive blends are composed of a mixture of an electron-donor polymer and an electron-accepor fullerene derivative, where the latter material is typically a soluble C 60-fullerene (PC 61 BM) or C 70-fullerene (PC 71 BM) derivative (Figure 1). The BHJ layer is sandwiched between charge carrier selective interlayers and the electrodes. The bottom electrode is typically indium tin oxide (ITO) or other transparent conductors. Interlayers choice governs the polarity of the photovoltaic cells. Metal oxides such as TiO x or ZnO are commonly used as electron selective layer whereas MoO x or conducting polymers (PEDOT:PSS) are used as hole transporting layers. An optimised BHJ layer requires specifi c phase segregation of the BHJ donor-acceptor components to allow optimum charge carrier photogeneration in the blend and charge perco-lation pathways for effi cient electron and hole collection to the respective electrodes. An important morphological parameter of the BHJ blend to achieve large PCEs is that nano-sized fullerene crystallites are necessary within the polymer matrix to prevent electron-hole recombination mechanisms. [ 4–7 ] Thus, the domain size must be in the order of the excitons diffusion length, which typically ranks from 3 to 30 nm. [ 8 ] Such optimal polymer-fullerene blend morphology is achieved with a different efficiency depending on the material combinations. [ 9 ] Optimized phase segregation can be promoted using appropriate solvent(s) and/or specifi c solvent additives during blend deposition as well as post-deposition fi lm processing such as thermal or solvent annealing. [ 10 ] Semicrystalline polymers such as poly(3-hexylth-iophene) (P3HT, Figure 1) tend to expel fullerenes during their crystallization into nano-objects upon drying of the solvent or during post-fi lm deposition thermal annealing. This property enabled to fi nely tune P3HT:PCBM blend morphology and led to a tremendous amount of data concerning OPV cells based on this specifi c polymer. [ 11 ] However, P3HT cells are severely limited in terms of the maximum achievable PCEs. Therefore, low band gap polymers, which can harvest a larger portion of the solar spectrum, were developed to reach greater performances. Unfortunately, several of these high-potential polymers are less crystalline and do not have such a strong tendency for molecular organization. As a consequence, manipulating BHJ morphology of less crystalline/amorphous polymers is not trivial. Solvent additives, such as 1,8-diiodooctane or 1,8-octanedithiol for example, enable to preferentially solvate fullerene derivatives rather than the polymer, were chosen to tune BHJ morphology and achieve effi ciencies >9%. Thus, the major problem that the The use of a bulk heterojunction (BHJ) blend of an electron-donor and an electron-acceptor organic semiconductors to fabricate photovoltaic solar cells and to understand fundamental light-to-charge phenomena in organic solids has attracted the interest of the international scientifi c community for the last 20 years. These efforts recently led to the demonstration of lab-scale organic photovoltaic (OPV) cells with power conversion effi ciencies (PCE) of 9.2% and 10.6% for single cells [ 1 ] and tandem cells [ 2 ] confi gurations, respectively. OPV cells are becoming a credible revolutionary thin-fi lm photovoltaic technology with advantages such as lightweight, mechanical fl exi-bility, roll-to-roll large area and low-cost solar module production. The three major challenges to OPV module realization are the cost of the active/encapsulation layers, effi ciency at module

Nonaqueous synthesis of uniform indium tin oxide nanocrystals and their electrical conductivity in dependence of the tin oxide concentration

Abstract: Indium tin oxide nanoparticles with tin oxide contents varying from 2 to 30 wt % have been synthesized via a nonaqueous sol−gel procedure involving the solvothermal treatment of indium acetylacetonate and tin tert-butoxide in benzyl alcohol. According to powder X-ray diffraction analysis combined with Rietveld refinement all the materials are crystalline with the cubic bixbyite structure of indium oxide without any indication of SnO2 as an additional phase. Transmission electron microscopy studies proved that the nearly spherical particles are relatively uniform in size and shape with crystallite sizes in the range of 5−10 nm. X-ray photoelectron spectroscopy results showed that the final composition of the nanoparticles coincided well with the initial indium acetylacetonate-to-tin tert-butoxide ratio. Furthermore, a high amount of oxygen vacancies was detected, which contribute to the good electrical conductivity of the nanoparticles. Conductivity measurements on the as-synthesized nanopowders pressed in...

Organic photovoltaic cells: history, principle and techniques

Abstract: In this review we present an overview of the different organic solar cells families. After recalling shortly the specificities of organic materials, the band structure, the electronic properties and the charge separation process in organic materials are shortly described. Then the new organic solar cell concepts are presented. Plastic organic solar cells consist either of two organic layers or a homogeneous mixture of two organic materials. One of them - either an organic dye or a semiconducting polymer - donates the electrons. The other component serves as the electron acceptor. Principies of these multi-layers and bulk heterojunctions are presented and discussed. Then some typical examples are presented, showing the fast evolution of the cells performances. Finally, a specific attention is devoted to the interfaces electrodes/organics. Indeed recent results show that, at least in the case of multi-layers cells, the introduction of thin buffer layers at the interfaces cathode/organic acceptor and/or anode/organic donor, can strongly improve the efficiency of the organic solar cells. About the interface organic acceptor/cathode, we report the influence of an exciton-blocking layer and/or an A1203 thin layer on the efficiency of CuPc/C60 based photovoltaic cells. The presence, or not, of a thin A1203 layer depends on the encapsulating process of the devices. In the case of glass/ITO/CuPc/C60/Al cells, the presence of an A1203 thin layer at the interface "organic acceptor/aluminium" increases strongly the open circuit voltage of the cells but decreases slightly their short circuit current and fill factor. In the case of glass/ITO/CuPc/C60/Alq3/Al cells, the open circuit voltage is systematically higher than without Alq3. However, in that case, the presence of A1203 does not improve significantly the cell performances. All these results are discussed in terms of series and shunt resistance values related to possible oxygen contamination and organic covalent action with the Al films. The effectiveness of these different phenomena depends on the presence, or not, of Alq3 and/or A1203 layers. About the interface anode/organic donor, it is shown that an ultra thin metallic film improves significantly the short circuit current and the cell performances. The anode in plastic solar cells, which is a transparent conductive oxide (TCO), is usually an indium tin oxide film (ITO). Indeed, when a ZnO anode is used, cells performances are far from those achieved with ITO. However, strong improvement of the cells efficiency is encountered when an ultra thin buffer layer is introduced between the ZnO and the organic film. The presence of this ultra thin buffer layer at the surface of the TCO allows decreasing the performance difference between the cells using ITO and those using ZnO. More generally such ultra thin buffer layer improves the solar cells performances