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The development of CdTe/CdS solar cells on flexible substrates is reviewed in this article. Photovoltaic structures on lightweight and flexible substrates have several advantages over the heavy glass based structures in both terrestrial and space applications. The cells mounted on flexible foil are not fragile, the requirements of the supporting structures are minimum and they can be wrapped onto any suitably oriented or curved structures. The specific power of the solar cells is an important factor in space applications and hence development of photovoltaic devices on light weight substrates is interesting. CdTe is one of the leading candidates for photovoltaic applications due to its optimum band gap for the efficient photo-conversion and robustness for industrial production with a variety of film preparation methods. Flexible solar cells with conversion efficiencies exceeding 11% have been developed on polyimide foils. The development of CdTe devices on metallic substrates is impeded due to the lack of a proper ohmic contact between CdTe and the substrate. The polymer substrate has the advantage that the devices can be prepared in both “superstrate” and “substrate” configurations.

A thin Ag layer embedded between layers of zinc tin oxide (ZTO) are compared to cells using an indium tin oxide electrode was investigated for inverted organic bulk heterojunction solar cells employing a multilayer electrode. ZTO/Ag/ ZTO (ZAZ) electrode is the preparation at room temperature, a high transparency in the visible part of the spectrum, and a very low sheet resistance comparable to treated ITO without the need for any thermal post deposition treatment as it is necessary for ITO. The In-free ZAZ electrodes exhibit a favorable work function of 4.3 eV and are shown to allow for excellent electron extraction even without a further interlayer. This renders ZAZ a perfectly suited bottom electrode for inverted organic solar cells with simplified cell architecture.

Phase separation of the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester(PCBM) active layer (ATL) was investigated by varying their relative ratio in the organic solar cells (OSCs).With the help of the UV/visible spectrophotometer, optical microscopy and scanning electron microscope,we found that the cluster of PCBM at the interface or surface was affected by Al cathode, the composition of the blends and thermal annealing. The disc-like shape crystals of PCBM substituted for the needle-like ones at higher PCBM compositions at the ATL/Al interface, which led to stronger contacts and bigger contact area. It could make short circuit current density increase, but may affect the blend morphology and result in parallel resistance and open circuit voltage decreased with the PCBM ratio increasing from 40 to 60%. The microstructure of the P3HT:PCBM ATL, determined by the composition dependent phase separation, supported the optimized performance of the OSCs with the composition of 40–50% PCBM.

Laser tube bending is a kind of plastic forming method with high flexibility, and is suitable for the low ductility material and thin thickness tube. This paper proposes a systematic scheme for three-dimensional tube bending, which forms the tube by varying the bending position and bending direction continuously. The bending part is simplified as a three-dimensional curve and then the curve is divided into segments and substituted with line sections. The scheme takes the angle between two adjacent segments as the laser bending angle at each bending position and the angle between two adjacent bending plane as the variation of bending direction. The effectiveness of proposed scheme is verified with the forming of a helical tube experimentally. The dimension errors of the formed helical tube are 6.25% in diameter and 7.59% in pitch respectively.

Laser cladding utilizes a laser as energy source to apply a layer of a desired material onto a substrate. As a complex thermal-mechanical process, laser cladding is not quite understood yet. In this paper, effects of process variables on temperature variation during laser cladding are investigated with finite element method. The powder feeding during cladding is taken into account by using the element’s functions of “death” and “birth”. This makes the analysis more accurately. The analysis results show that the maximum temperature at the melting pool during cladding is directly proportional to the laser power and preheated temperature. The maximum cooling rate at the melting pool is inversely proportional to them. Increasing the preheated temperature can decrease the cooling rate of the clayed layer effectively. Increasing the laser power can also decrease the cooling rate, but the effect is not obvious.

The cracks in clad layer are the most often defects in laser cladding of low ductility materials. This paper reports the efforts of crack prediction with finite element method. The process is modeled with commercial FEM software package ANSYS and the thermal-mechanical analysis is performed to inquire the strain-stress variation during cladding, especially the variation around the moment of solidification. The analysis result shows that, by the end of cladding, the clad layer is in tension stress and the stress values are varied in directions. The tension stress along the cladding direction is the maximum one, which causes the cracking in clayed layer. Increasing the preheating temperature of substrate is an effective way to avoid the crack generation.

An efficient flexible organic solar cell was presented. The highest power conversion efficiency (PCE) of 3.2% and 2.5% were achieved on glass substrate and flexible substrate individually. The device photovoltaic properties were discussed in terms of the band diagrams and series resistance of the devices. Also the properties of nickle oxide thin film on different conditions were investigated too. Room temperarure sputtered and highly conductive nickle oxide (NiO) thin film as hole transporting layer in the cells. The strcture of this kind of devices is PET/ITO/NiO/P3HT: PCBM [regioregular of poly (3-hexylthiophene):(6,6)-phenyl C61 butyric acid methyl ester] /Al. On the study of characteristics of Nickle oxide thin film, such as sputtering temperature, thickness, and oxygen proportion, we found that NiO with 10 nm and sputtered at room temperature shows the best photovoltaic properties.

Phase separation of the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester(PCBM) active layer (ATL) was investigated by varying their relative ratio in the organic solar cells (OSCs).With the help of the UV/visible spectrophotometer, optical microscopy and scanning electron microscope,we found that the cluster of PCBM at the interface or surface was affected by Al cathode, the composition of the blends and thermal annealing. The disc-like shape crystals of PCBM substituted for the needle-like ones at higher PCBM compositions at the ATL/Al interface, which led to stronger contacts and bigger contact area. It could make short circuit current density increase, but may affect the blend morphology and result in parallel resistance and open circuit voltage decreased with the PCBM ratio increasing from 40 to 60%. The microstructure of the P3HT:PCBM ATL, determined by the composition dependent phase separation, supported the optimized performance of the OSCs with the composition of 40–50% PCBM.

This paper presents an efficient flexible organic solar cell with room temperarure sputtered and highly conductive nickle oxide (NiO) thin film as hole transporting layer. The strcture of this kind of devices is PET/ITO/NiO/P3HT: PCBM [regioregular of poly (3-hexylthiophene):(6,6)-phenyl C61 butyric acid methyl ester] /Al. On the study of characteristics of Nickle oxide thin film, such as sputtering temperature, thickness, and oxygen proportion, we found that NiO with 10 nm and sputtered at room temperature shows the best photovoltaic properties. The highest power conversion efficiency (PCE) of 3.26% and 2.5% were achieved on glass substrate and flexible substrate individually. The device photovoltaic properties were discussed in terms of the band diagrams and series resistance of the devices. Also the properties of nickle oxide thin film on different conditions were investigated too.

The preparation and characteristics of ZnO(Zinc oxide) co-sputtered TaO (Ta oxide) electrodes(ZTO) grown on glass substrates using a specially designed composite target for use in organic solar cells are described. It was found that both the electrical and optical properties of the ZTO films were critically dependent on the Ar/O2 flow ratio and sputtering power. In addition, all ZTO electrodes show amorphous structure regardless of the Ar/O2 flow ratio, due to the low substrate temperature. We obtained the ZTO electrode with sheet resistance of 30 Ohm/square and average optical transmittance of 80% in room temperature. The conversion power efficiency by using ZTO electrode at optimized conditions is 2.6 %.

This paper presented an efficient flexible bulk-heterojunction [regioregular of poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61 butyric acid methyl ester (PCBM)] solar cells with a highly transparent and electrical conductive NiO film as hole-transporting layer (HTL) on optimized Al doped zinc oxide (AZO) substrate. The strcture of this kind of devices is PET/AZO/NiO/P3HT: PCBM /Al. The highest power conversion efficiency (PCE) on glass substrate is 3.15%, and 1.66% on flexible substrate. The physical and electrical properties of AZO thin film were discussed, and the device photovoltaic characteristics were investigated in detail.

This paper presents a new buffering layer(nickle oxide thin film) of organic solar cells. Nickle Oxide(NiO) thin film is a good alternative of hole tansporting layer. We investigates the film from physical and electrical aspects, such as morphology, deposition temperature, thickness etc. We find that the optimum fabrication conditions are: room temperature deposition, 10nm of thickness, and 30% oxygen proportion. The device strcture is Anode/NiO/P3HT[regioregular of poly(3-hexylthiophene)]: PCBM[(6,6)-phenyl C61 butyric acid methyl ester] /Al. And the best power conversion efficiency of device we got with NiO buffering layer is 2.49%, which is hundred times of ones without NiO buffering layer.

Laser tube bending is a spring-back-free noncontact forming method that has received considerable attention in recent years. Compared to mechanical bending, no hard tooling, dies, or external force is used in laser bending, thus the cost is greatly reduced for small-batch production and prototyping. Some quality issues, such as cross sectional distortion and intrados protrusion exist in laser bending and have growing tendency when the tube’s wall being thinner. This paper investigates the effects of process parameters on the deformation of thin wall tube through numerical simulations and experiments. The dimensions of the tube analyzed are 32 mm in outer diameter and 0.48mm in wall thickness. A three-dimensional transient thermo-mechanical analysis using the finite element method is carried out to simulate the laser bending process with some results validated by experiments. The effects of process parameters on the deformation of thin wall tubes are discussed in detail.

In this paper, we present a comprehensive experimental study on the blanking process of thick wall metal tube. The tube used in experiment is GCr15 bearing steel with 56 mm in outer-diameter and 6.5 mm in wall-thickness. The experiment was conducted with an experimental blanking apparatus, which consists of fixed die, moving die and inner cores rod. Two blanking schemes, single punching and cross punching, are compared through experiment. The single punching scheme is realizable for tube blanking but the effect is not acceptable in recent stage. Cross scheme is a better choice for tube blanking as the surface roughness in blanking section can be greatly improved. In cross scheme, the first penetration depth is the key factor to final blanking quality. It was found through experiment that the adequate first penetration depth is around 60 percent of the wall thickness of the tube.

The knowledge of the flow behavior of metals during hot deformation is of great importance in determining the optimum forming conditions. In this paper, the flow stress of 00Cr17Ni14Mo2 (ANSI 316L) austenitic stainless steel in elevated temperature is measured with compression deformation tests. The temperatures at which the steel is compressed are 800-1100°C with strain rates of 0.01-1s-1. A mathematical regression model is proposed to describe the flow stress and the validation of the model is conducted also. The proposed model can be used to predict the corresponding flow stress-strain response of 00Cr17Ni14Mo2 stainless steel in elevated temperature for the numerical simulation and design of forming process.

With the aid of SEM and DTA, the microstructures of metal side of the interface between Ti48Al2Cr2Nb alloy and Y 2 O 3 , ZrO 2 (Y 2 O 3 stabilized), ZrO 2 (MgO stabilized), and Zircon sand were investigated, respectively. The initial reaction temperatures were measured for Ti48Al2Cr2Nb alloy and Y 2 O 3 , ZrO 2 (Y 2 O 3 stabilized), ZrO 2 (MgO stabilized) and Zircon sand, respectively. The results show that the microstructure is the coarsest with rosettes-like shape after Ti48Al2Cr2Nb alloy reacts with Zircon sand, and even the smallest with granular-like shape after Ti48Al2Cr2Nb alloy reacts with Y 2 O 3 . The order of the initial reaction temperatures between Ti48Al2Cr2Nb alloy and four oxide ceramic materials is non-reaction at 1500, 1400, 1380, and 820 °C, respectively.

In term of newly developed titanium alloys Ti-6Al-4V-4Zr-Mo (Ti6441) modified from the commercial Ti-6Al-4V alloys, the adiabatic shear behaviors of equiaxed and lamellar microstructures were investigated. Unlike the Ti-6Al-4V alloys, Ti6441 alloys with the lamellar microstructure are less susceptive to adiabatic shear bands (ASBs), compared with the equiaxed one. In particular, the ASBs branch off in the lamellar microstructure, requiring additional energy by consuming metal bulk plastic deformation work. Besides, forced shearing experiment results show the lamellar microstructure exhibits outstanding dynamic ductility in contrast with the equiaxed one, though both microstructures perform the same strength value.

Raman spectroscopy is used to monitor hydrogenation of graphene on polydimethylsiloxane (PDMS) as well as on SiO2/Si substrates. It is found that hydrogenation of graphene on SiO2/Si is much more feasible than that on PDMS. For graphene on PDMS substrates, hydrogenation of graphene is favored on very flexible substrates. The substrate (SiO2/Si and PDMS) and flexibility (PDMS with different flexibility) dependent hydrogenation behavior can be understood by different interactions between graphene and substrate. The interaction between graphene and SiO2/Si is relative weak (van der Waals force) and the interaction between graphene and PDMS is relative strong, where substrate induced prestrain in the graphene layer is observed. For graphene embedded on the PDMS substrate, the more flexible the substrate is, the weaker the interaction between PDMS and graphene. The understanding of the effect of PDMS's flexibility on hydrogenation of graphene will be helpful for graphene based flexible electronics.

Critical current densities of YBCO single crystal have been improved with ion implantation. The sample was implanted with 120keV, 1.4×1016 O+ ions/cm2, which made the surface layer amorphous. After ion implantation the sample was re-annealed at 5000°C for 80h and then cooled at of 0.82°C/min in flowing O2 gas. The critical current density of single crystal YBCO sample increased by about 100% as a result of ion implantation and crystallinity almost perfectly recovered as it was befor ion implantation by post annealing and exhibited Tc of 90K.