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Conceived by Iranian researchers, the new conductive adhesive ink is made of polymethyl methacrylate (PMMA) and is used as an intermediate layer between the hole transport layer of the cell and the carbon sheet. It reportedly ensures greater cell stability while providing remarkable efficiency.
A group of scientists led by Irans Sharif University of Technology has developed a new conductive adhesive ink that can be used as an interfacial adhesive layer in perovskite solar cells.
“The goal of the adhesive ink is to improve the stability and efficiency of the cells,” Nima Taghavinia, lead author of the research, explains to pv magazine . “We have developed a simple, low-cost process that is compatible with large surface applications.”
The adhesive is made of polymethyl methacrylate (PMMA), a polymer widely used as a substitute for glass in various industries due to its low cost, its excellent mechanical, electrical and optical properties, its thermal and environmental stability, its low weight and great light transparency. It is used as an interfacial layer between the hole transport layer (HTL) of the cell, made of copper indium sulfide (CuInS2) nanoparticles, and a carbon top sheet based on high conductivity carbon black (HCCB).
The adhesive was embedded in a cell formed by a fluorine-doped tin oxide (FTO) substrate, an electron transport layer (ETL) based on carbon dioxide and titanium (c/TiO2), a mesoporous TiO2 layer, the perovskite absorber, the CuInS2 based HTL and the carbon topsheet with HCCB.
The researchers noted that this cell configuration without the new adhesive had previously proven unstable, as the carbon electrodes frequently detached after measurements were made.
“The conductive adhesive ink was poured drop by drop onto the carbon sheet with a surface area of ??0.27 cm2,” the researchers explain, referring to the adhesive deposition process. “Next, the carbon sheet was transferred to the already prepared FTO/c-TiO2/mp-TiO2/perovskite/CuInS2 glass stack, so that the adhesive ink was in contact with the HTL.”
Through a series of tests, the research group discovered that PMMA is the key to achieving stable and reliable adhesion of the carbon sheet to the cell. He also explained that adding the CuInS2 nanoparticles to the ink makes the adhesive consistent with the underlying HTL, with the CuInS2 nanoparticles contributing to the hole transfer mechanism.
“Our results showed that the addition of 2 wt% HCCB nanoparticles to the PMMA/CIS mixture with a ratio of 1:3 leads to the maximum conductivity for the adhesive interfacial layer achieved, resulting in the maximum efficiency of the 17 .2%, which is comparable to that of homologous gold-based cells (18.2%),” the academics stated. “In addition, using the proposed carbon laminate electrode we achieved a long-term stability of around 92% after 54 days of storage, which is an improvement of around 17% compared to the stability of gold-based counterparts.”
Their findings are available in the study “ A conductive adhesive ink for carbon-laminated perovskite solar cells with enhanced stability and high efficiency ,” published in Solar Energy . |
