Thin‐film solar cells: an overview

Abstract

Thin film solar cells (TFSC) are a promising approach for terrestrial and space photovoltaics and offer a wide variety of choices in terms of the device design and fabrication. A variety of substrates (flexible or rigid, metal or insulator) can be used for deposition of different layers (contact, buffer, absorber, reflector, etc.) using different techniques (PVD, CVD, ECD, plasma‐based, hybrid, etc.). Such versatility allows tailoring and engineering of the layers in order to improve device performance. For large‐area devices required for realistic applications, thin‐film device fabrication becomes complex and requires proper control over the entire process sequence. Proper understanding of thin‐film deposition processes can help in achieving high‐efficiency devices over large areas, as has been demonstrated commercially for different cells. Research and development in new, exotic and simple materials and devices, and innovative, but simple manufacturing processes need to be pursued in a focussed manner. Which cell(s) and which technologies will ultimately succeed commercially continue to be anybody's guess, but it would surely be determined by the simplicity of manufacturability and the cost per reliable watt. Cheap and moderately efficient TFSC are expected to receive a due commercial place under the sun. Copyright © 2004 John Wiley & Sons, Ltd.

Effect of hydrogen on surface texturing and crystallization of a-Si:H thin film irradiated by excimer laser

“…However, crystalline silicon suffers from the disadvantage of high material cost since relatively large thicknesses are required primarily due to its low absorption coefficient. Recently, thin film absorbers are becoming more attractive based on their potential for low-cost modules, possibility to create tandem junctions and large-scale manufacturability [1][2][3]. a-Si:H is the most popular material for use in thin film form due to its low energy economy (cost/watt).…”

Nanostructuring methods for enhancing light absorption rate of Si-based photovoltaic devices: A review

“…14 Although a-Si:H solar cells are subject to the Staebler-Wronski effect, which is caused by light-induced degradation related to a creation of defect acting as non-radiative recombination centers, it is also partially overcome by reducing the thickness of the a-Si:H layer in solar cells. 1,14,16 However, as in the case of the a-Si:H thin film solar cells, it has no chance to have less than 1 µm of thickness in order to absorb sufficient light spectrum unlike the minority carrier diffusion length has the typical length of the 300 nm. 17 This difference of the length for sufficient light absorption and diffusion length causes significant reduction of the Si-PV power generation due to a lack of light absorption and the loss of the carrier collection in the electrodes.…”

“…Therefore, the development of the doping techniques for hydrogenated amorphous silicon (a-Si:H) has received great attention since it has higher absorptivity than bulky Si based solar cell by help of thin film process with conventional thin film deposition techniques. 14,15 This high absorption of light in a varied spectrum resulted from the high structural disorder in the material allowing all optical transition, while the disorder simultaneously served as core part of recombination which highly reduces the carrier lifetime. 10,14 However, during the deposition of a-Si:H, 10% of the hydrogen incorporated greatly reduced the density of disorder, so it is considered that a-Si:H is the most suitable materials itself for substrate of thin film solar cells as well as substrate for nanostructure.…”

“…14,15 This high absorption of light in a varied spectrum resulted from the high structural disorder in the material allowing all optical transition, while the disorder simultaneously served as core part of recombination which highly reduces the carrier lifetime. 10,14 However, during the deposition of a-Si:H, 10% of the hydrogen incorporated greatly reduced the density of disorder, so it is considered that a-Si:H is the most suitable materials itself for substrate of thin film solar cells as well as substrate for nanostructure. 14 Although a-Si:H solar cells are subject to the Staebler-Wronski effect, which is caused by light-induced degradation related to a creation of defect acting as non-radiative recombination centers, it is also partially overcome by reducing the thickness of the a-Si:H layer in solar cells.…”

Pentacene/K12 solar cells formed by organic vapor phase deposition

“…2 However, the efficiency and stability of organic solar cells still have to be improved to compete with other photovoltaic thin film technologies such as CdTe, copper indium gallium selenide, or copper zinc tin sulphide. 3 To date, the combination of the polymers P3HT∕PC 61 BM is one of the most well researched. [4][5][6] To surpass current efficiency limits and to ease mass production, 7 new molecules that can be processed by low-temperature evaporation and/or by solution-based processes have to be evaluated.…”