A study published in the International Journal of Technology (2018) brings promising findings from the materials laboratory at Universitas Indonesia: third-generation solar cells based on synthetic dyes\u2014known as dye-sensitized solar cells (DSSCs)\u2014can perform significantly better simply by changing how titanium dioxide (TiO\u2082) nanoparticles are prepared. Dr. drg. Bambang Priyono, S.U., and a team of researchers from the Department of Metallurgical and Materials Engineering, Faculty of Engineering, Universitas Indonesia, found that hydrothermal treatment at 120\u00b0C produced an open-circuit voltage (Voc) of 320 millivolts\u201415 times higher than the 21 millivolts produced by the conventional aerogel method. The research was conducted at the Universitas Indonesia campus in Depok and published in 2018, with the aim of identifying a more efficient and environmentally friendly preparation technique as an alternative to fossil-based energy.<\/p>\n\n\n\n
DSSC technology is not new, but it continues to attract attention for a simple reason: it is inexpensive and relatively easy to manufacture. Unlike conventional silicon solar panels, which require complex and costly fabrication processes, DSSCs work somewhat like photosynthesis\u2014dye molecules absorb light and then release electrons that flow as an electric current.<\/p>\n\n\n\n
A key component of the system is a TiO\u2082 semiconductor layer that acts as the photoelectrode. This layer captures electrons from the dye molecules and transfers them to the external circuit. The better the crystal structure of the TiO\u2082 and the larger its surface area, the more dye molecules it can absorb and the greater the voltage it can generate.<\/p>\n\n\n\n
The challenge is how to prepare TiO\u2082 with both high crystallinity and a large surface area. These two properties often work against each other: processes that improve crystallinity tend to reduce surface area.<\/p>\n\n\n\n
The research team tested two different approaches to address this challenge.<\/p>\n\n\n\n
The first approach used supercritical extraction (SCE) to produce TiO\u2082 aerogel. In this process, CO\u2082 under supercritical conditions is used to extract the solvent from the gel, leaving behind a highly porous network. The results were impressive in terms of surface area: 110.31 m\u00b2\/g, the highest value among all the samples tested. However, the crystallinity of this material was lower than that of the hydrothermally treated samples.<\/p>\n\n\n\n
The second approach involved hydrothermal treatment at three different temperatures\u2014100\u00b0C, 120\u00b0C, and 150\u00b0C\u2014followed by drying and multi-step calcination at 150\u00b0C, 300\u00b0C, and 420\u00b0C. This multi-step calcination process, rather than direct single-stage calcination, was specifically designed to prevent the porous network from collapsing due to sudden temperature increases.<\/p>\n\n\n\n
The results were quite surprising. The sample hydrothermally treated at 120\u00b0C had the lowest band-gap energy, at 3.29 eV, approaching the ideal value of 3.28 eV for the anatase phase of TiO\u2082. This indicated optimal crystallinity. When tested as a DSSC using a 50-watt projector lamp, this sample produced a Voc of 320 mV, far exceeding that of the other samples.<\/p>\n\n\n\n
\u201cPre-hydrothermal treatment can make stiff Ti\u2013OH networks become more flexible, leading to the formation of Ti\u2013O\u2013Ti arrangements after completion of the hydrolysis process. These Ti\u2013O\u2013Ti structures improve the crystallinity of TiO\u2082 and lead to a better performance of the material.\u201d \u2014 Bambang Priyono et al., International Journal of Technology, 2018<\/em><\/p>\n\n\n\n Why 120\u00b0C rather than 150\u00b0C, which would logically provide more heat?<\/p>\n\n\n\n The explanation lies at the molecular level. Hydrothermal treatment works by breaking down rigid Ti\u2013OH networks\u2014structures that can inhibit the growth of TiO\u2082 crystals. At 120\u00b0C, these networks are sufficiently softened to allow the formation of more orderly and flexible Ti\u2013O\u2013Ti bonds, resulting in optimal crystallinity.<\/p>\n\n\n\n At 150\u00b0C, although the crystallite size was larger (9.73 nm compared with 7.79 nm at 120\u00b0C), DSSC performance actually decreased to 160 mV. The research team suspected that this was related to variations in the thickness of the TiO\u2082 layer on the conductive glass, a random variable that needs to be more tightly controlled in future studies.<\/p>\n\n\n\n Analysis of scanning electron microscopy (SEM) images showed that particles treated at 120\u00b0C had smoother edges and sizes ranging from 127 to 233 nm, making them larger and more uniform than the particles treated at 100\u00b0C, which remained sharp and rough. This morphology contributed to a more uniform distribution of Ti\u2013O\u2013Ti structures, ultimately supporting better photoelectrochemical performance.<\/p>\n\n\n\n This research has not yet produced a ready-to-install rooftop solar panel. The Voc measurements were conducted using a projector lamp rather than full sunlight, and production remains at the laboratory scale. Nevertheless, the study addresses a fundamental question that has long challenged DSSC development: which preparation technique is the most promising?<\/p>\n\n\n\n Based on these data, the answer is hydrothermal treatment at 120\u00b0C combined with multi-step calcination. This method outperformed the aerogel approach in terms of Voc, although the aerogel still had the advantage in surface area. Combining the two approaches\u2014or further modifying them\u2014could hold the key to truly efficient next-generation DSSCs.<\/p>\n\n\n\n These nanoparticles, only a fraction of a micrometre in size, hold potential far beyond their physical dimensions. And from the materials laboratory in Depok, another small step toward more affordable solar energy has been taken.<\/p>\n\n\n\n Authors: Achmad Zam Zam Aghasy, DDS, M.Kes.; Hazra Alifia Muharam<\/p>\n\n\n\n Photo: Pexels<\/p>\n\n\n\n Sumber DOI: https:\/\/doi.org\/10.14716\/ijtech.v9i5.1067<\/p>","protected":false},"excerpt":{"rendered":" Sebuah penelitian yang diterbitkan dalam International Journal of Technology (2018) membawa kabar menarik dari laboratorium material di Universitas Indonesia: sel surya generasi ketiga berbasis pewarna sintetis \u2014 yang dikenal sebagai dye-sensitized solar cell (DSSC) \u2014 bisa bekerja jauh lebih baik hanya dengan mengubah cara nanopartikel titanium dioksida (TiO\u2082) disiapkan. Dr. drg. Bambang Priyono, S.U. bersama […]<\/p>\n","protected":false},"author":615,"featured_media":21008,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[359,136],"tags":[303,307,289,295,297],"class_list":["post-21000","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-artikel","category-berita-terbaru","tag-sdg-13-aksi-iklim","tag-sdg-17-kemitraan-untuk-mencapai-tujuan","tag-sdg-3-kesehatan-dan-kesejahteraan-yang-baik","tag-sdg-7-energi-yang-terjangkau-dan-bersih","tag-sdg-9-industri-inovasi-dan-infrastruktur"],"gutentor_comment":0,"yoast_head":"\nThe Secret Behind 120\u00b0C<\/h2>\n\n\n\n
Clean Energy Begins at the Nanoscale<\/h2>\n\n\n\n