Emerging Solar Technologies: Perovskite Solar Cell

Conversion of sunlight to electricity with high conversion efficiencies at low cost is possible with emerging photovoltaic technologies. Organic–inorganic halide perovskite, a newcomer in the solar cell industry has proved its potential for increasing efficiency rapidly from 3.8% in 2009 to 22.1% in 2016. High efficiency, flexibility, and cell architecture of the emerging hybrid halide perovskite have caught the attention of researchers and technologists in the field. This article focuses on the emergence, properties, and current research status of hybrid perovskite solar cells

Performance Analysis and Fault Diagnosis Method for Concentrator Photovoltaic Modules

Concentrator Photovoltaic (CPV) systems use high efficiency multi-junction solar cells with efficiencies >40%, but the module efficiency is often much lower. The increased complexity of a CPV module, with optics, receiver and the tracker gives an increased probability that faults will arise during the operational lifetime. In addition, a location like India has varied atmospheric conditions that further complicates the diagnosis of faults. It is therefore important to decouple effects due to the external environment (such as the atmosphere) from effects due to the degradation of the module. By applying a computer model to outdoor CPV test data in Bangalore, India we have established a method to assess the performance of the CPV module and finally we present a method to diagnose faults in the module.Comment: 7 pages, 12 figure

Measurement under pressure of thermoelectric power along the thickness of a thin specimen

A method of measuring under pressure the thermoelectric power along the thickness of thin specimens is described. This method is useful in measuring thermoelectric power in a direction13; perpendicular to the cleavageplane of a crystal

Effect of temperature and soaking time on the synthesis of Mo(Al,Si)2

Mo(Al,Si)2 has been prepared by hot pressing elemental powders of Mo, Al and Si, at 1200-1700xB0;C and 22 MPa. Mo5Si3 or Mo5Si3C have been observed as minor phases in all the samples with 1300xB0;C being the best processing temperature for synthesizing Mo(AlSi)2: with minimum amount of impurities. As the soaking time increases, the amount of impurity phases also increases. xA9; 2001 Elsevier Science Ltd and Techna S.r.l. All rights reserved

Aluminum infiltration into Molybdenum Silicide preforms

The presence of MosSi3 in MoSi2 preforms hinders the reactive infiltration of aluminum. To understand the role of Mo5Si3, the kinetics of aluminum infiltration into pure MosSi, is studied.Irrespective of the initial composition (MoSi2 or Mo5Si3) of the preform, the final product always contains Mo(Al,Si)2. However, the aluminum content in the two cases is different: when the preform is MoSi2, the aluminum content is 14-18 at.%,and, when the preform is MosSi3, the aluminum content is 25-27 at.%. The activation energy for the reactive infiltration of aluminum into the MosSi3 preform is 26 kj/mol

Oxidation of MoSi2 and MoSi2-based materials

Oxidation experiments, at 500CC, of MoSi z and MoSi2-based compounds such as Mo(A1,Si)2 and MoSiz + I wt% C compacts have been carried out. These compacts were prepared by in situ synthesis and a compaction method, starting from the elemental powders. For comparison, commercial MoSi z and Mo(AI,Si)2 infiltrated into SiC preform were also studied under similar conditions. It was found that the synthesized high density MoSi2 and Mo(AI,Si)2 infiltrated into SiC preform did not show any oxidation even after 100 h of heating in air. The colour of the polished surfaces of commercial MoSi2, Mo(AI,Si)2 and MoSiz + 1 wt% C had changed. The SEM of Mo(At,Si)2 showed open blisters with rods of MoO3 in them whereas MoSiz + I wt% C surface had MoO3 rods but no blisters and the oxidation was superficial with no penetration into the compact. It is suggested that in compounds, the presence of small amounts of impurities is not as detrimental to pesting as presence of defects like open pores or cracks. Hence, high density of the compact is essential for the prevention of complete disintegration of the compac

MoSi2 and MoSi2 - Based Materials as Structural Ceramics

MoSi2, because of its mixed covalent-metallic atomic bonding, is a borderline intermetallic compound which has many attractive properties that can be exploited in high temperature structural applications . Foremost amongst these is its stability in corrosive atmospheres up to about 1600 C . However, there are a few undesirable prooperties that need to be addressed before it can become a viable material in high temperature applications . Since MoSi2 forms thermodynamically stable composites with both metals and ceramics, many reinforcing materials are incorporated into the matrix to improve the fracture toughness and creep properties . The low temperature oxidation can be controlled by compaction to high density . Mo(Al, Si)2, a related ceramic, which also has good high temperature properties besides having better low temperature toughness . However, presence of Mo5Si3 phase, which has low oxidation resistance, needs to be controlled . This is being achieved by synthesizing Mo(Al, Si)2 at as low a temperature as 1300 C. This article summarizes important attempts that are made in improving the properties of MoSi2 by reinforcement with other materials

Fabrication of molybdenum disilicide components by slip casting

Molybdenum disilicide (MoSi2) has many desirable properties which make it an excellent material for aerospace applications. This demands a reliable processing route to manufacture components with complicated shapes. The suitability of using slip-casting technique to fabricate MoSi2 components has been studied. In this study, we have optimized the pH of the aqueous solution to get a reasonable suspension without adding any dispersing agents or sintering aids. Further, it is found that the 50 wt.% solid loading is best to get a compact of 92% density. xA9; 2002 Elsevier Science B.V. All rights reserved

Order-disorder transitions in c60 and C70

In recent years enormous effort has been put in understanding the chemical and physical properties of Cm and C70. Order-disorder transition in Cso occurs13; around 250 K at ambient pressure. At the transition freely rotating molecules get orientationally ordered in a simple cubic lattice. Application of pressure increases the transition temperature at a rate of Y 10 K kbar-', indicating that pressure favours the ordered state. The DSC and x-ray studies on C70 indicate two phase transitions, one around 270 K and the other around 34013; K at room pressure. These transitions also occur at higher temperatures at higher pressures. Application of pressure is found to lift the degeneracy of the energetically equivalent rotational configurations. The high pressure studies are reviewed in the light of existing literature