Laser assisted dye-sensitized solar cell sealing: From small to large cells areas

Abstract

The long-term stability problem of dye sensitized solar cells (DSCs) modules is essentially related to their sealing. Thermoplastic sealants are normally used to bond the two glass substrates of a DSC.However, these thermoplastic sealants, such as Surlyn ® , are permeable towards ambient water vapor, UV sensitive and they cannot be used above 60 °C [1]. Sealing is therefore the Achilles' heel of DSCs, which is presently preventing their commercialization.Laser assisted glass-frit sealing can be a very interesting alternative sealing technique, as it has been demonstrated on microelectromechanical systems (MEMS) assembly. However, for these applications the laser is shot around the sealing perimeter several times in a loop pattern. Nevertheless, for sealing large areas without heating the samples this method cannot be applied since the laser loop takes more than 1second, which is too long for an effective low-temperature glass-frit sealing.In the present work is described a laser assisted sealing technique that is independent of the sealing border path format applied to several cells' and modules' shapes and sizes. This technique is suitable for DSCs manufacture and can be implemented in an inline production plant. For the same cell format, efficiencies of the glass-sealed and conventional sealing were compared. Stability studies were also presented to evidence the effectiveness of the hermetic sealing obtained with the sealing assisted technique applied to DSCs.

Aqueous dye-sensitized solar cells

“…), UV curable glues 37 and glass frit (GF). 283,284 GF is believed to be one of the strongest candidate as a sealant material in DSSC glass modules, as it possesses the same characteristics of the substrate, thus optimum compatibility; moreover, it is non-permeable, stable under UV light and at elevated temperatures. [285][286][287] On the other hand, it has been quite difficult to find lead-free GF, 288 demonstrating at the same time low melting temperature and high chemical stability towards the redox mediator.…”

Laser Processing in the Manufacture of Dye‐Sensitized and Perovskite Solar Cell Technologies

“…In Refs. , a method of sealing DSSCs by means of a laser‐processed glass frit is reported (see Figure ). It consists of scanning the laser beam several times at high speeds along the glass frit cord (which, being dark, strongly absorbs the laser beam, whereas the glass substrates, being transparent, do not), inducing a quasi‐continuous temperature increase at every pass (see Figure , top).…”