Strategies of Perovskite Mechanical Stability for Flexible Photovoltaics

The market’s increasing demand for portable electronic products has made the research of flexible devices very attractive. Flexible solar cell is one of the most eye-catching existences in the field...

Demonstration of Solar Cell on a Graphite Sheet with Carbon Diffusion Barrier Evaluation

An amorphous Si (a-Si) solar cell with a back reflector composed of zinc oxide (ZnO) and silver (Ag) is potentially the most plausible and flexible solar cell if a graphite sheet is used as the substrate. Graphite supplies lightness, conductivity and flexibility to devices. When a graphite sheet is used as the substrate, carbon can diffuse into the Ag layer in the subsequent p-i-n process at 200–400 °C. To prevent this, we added an oxide layer as a carbon diffusion barrier between the carbon substrate and the back reflector. For the carbon diffusion barrier, silicon oxide (SiO2) or tin oxide (SnOx) was used. We evaluated the thermal stability of the back reflector of a carbon substrate using secondary-ion mass spectrometry (SIMS) to analyze the carbon diffusion barrier material. We confirmed the deposition characteristics, reflectance and prevention of carbon diffusion with and without the barrier. Finally, the structures were incorporated into the solar cell and their performances compared. The results showed that the back reflectors that were connected to a carbon diffusion barrier presented better performance, and the reflector with an SnOx layer presented the best performance.

Design of RF Rectenna on Thin Film to Power Wearable Electronics

This chapter reports a hybrid wearable energy harvesting system. Integration of microwave antenna on thin film amorphous silicon solar cell creates a hybrid system that can harvest both the solar and microwave energies. The antenna designed on solar cell will harvest the microwave energy at dual frequencies 1.85 GHz and 2.45 GHz with an effective return loss of 28dB and 27dB respectively. A complete hybrid harvesting system consist of a flexible solar cell, antenna, voltage doubler, and impedance matching dual band filter. The rectifier, designed on a rigid glass-reinforced epoxy substrate, is a voltage doubler and a matching circuit is designed by microstrip lines is used.

Advanced materials for flexible solar cell applications

The solar power is one of the most promising renewable energy resources, but the high cost and complicated preparation technology of solar cells become the bottleneck of the wide application in many fields. The most important parameter for solar cells is the conversion efficiency, while at the same time more efficient preparation technologies and flexible structures should also be taken under significant consideration [1]. Especially with the rapid development of wearable devices, people are looking forward to the applications of solar cell technology in various areas of life. In this article the flexible solar cells, which have gained increasing attention in the field of flexibility in recent years, are introduced. The latest progress in flexible solar cells materials and manufacturing technologies is overviewed. The advantages and disadvantages of different manufacturing processes are systematically discussed.

Development of Back and Front Contacts for CdTe Layer in Tandem Flexible Photoelectric Converters on Basis of CdTe/CuInSe2

By the method of nonreactive high-frequency magnetron sputtering on Upilex polyimide films, transparent and conductive layers of ITO were obtained. These layers, after high-temperature annealing, at temperatures typical for the solar cell formation, had a resistance of 11 ohm/□ and a transmittance of up to 72%. The use of such an ITO layer with the addition of a 100 nm thick layer of undoped zinc oxide, as the front contact, and Cu/ITO composition, as the back contact, made it possible to obtain a flexible solar cell polyimide/ITO/CdS/CdTe/Cu/ITO with an efficiency of 10.4%. With a thickness of the base layer of cadmium telluride 2.5 μm, the average transmittance of the SC in the 850-1100 nm wavelength range is 46.8%. The developed design of a flexible solar cell based on cadmium telluride due to the use of a transparent back contact with a comb metal electrode is easily interfaced with existing designs of flexible solar cells based on copper and indium diselenide, which allow the formation of flexible tandem photoelectric converters CdTe/CuInSe2.