Imagine a material that is lighter than air, yet capable of capturing light and converting it into electricity. This is the remarkable potential of aerogel, and a research team from the Department of Metallurgical and Materials Engineering, Universitas Indonesia, successfully synthesized it from titanium dioxide (TiO\u2082) using a supercritical CO\u2082 extraction technique.\nThe study, published in Advanced Materials Research Vol. 789 (2013), was led by Dr. drg. Bambang Priyono, S.U., together with Prof. Dr. Ir. Akhmad Herman Yuwono, M.Phil.Eng., and several collaborators.\nThe results were remarkable: solar cells based on TiO\u2082 aerogel achieved an open-circuit voltage (Voc) of 21.40 mV, nearly 20 times higher than solar cells made from the comparison material, xerogel, which produced only 1.10 mV.<\/p>\n\n\n\n
To understand why the results were so significant, it is necessary to briefly explore the world of nanoscale materials.<\/p>\n\n\n\n
TiO\u2082, or titanium dioxide, is not an unfamiliar material. It can be found in white wall paint, sunscreen products, and even toothpaste. However, at the nanometer scale, its properties change dramatically: its surface area increases substantially, allowing it to function as a photoelectrode in dye-sensitized solar cells (DSSCs), a type of third-generation solar cell that imitates the process of photosynthesis.\nThe working principle is as follows: dye molecules attached to the surface of TiO\u2082 absorb sunlight and inject electrons into the semiconductor material, generating electrical current.<\/p>\n\n\n\n
The challenge is that the larger the surface area of TiO\u2082, the more dye molecules can attach, and the greater the potential electrical output. This is where aerogel demonstrates its advantage.<\/p>\n\n\n\n
The production of aerogel begins with the sol-gel process, a wet chemical technique in which a solution of titanium tetra-n-butoxide in ethanol is gradually transformed into a gel. The gel is then dried not through conventional heating, but using supercritical CO\u2082, a condition in which CO\u2082 exists simultaneously between liquid and gas phases at 100 bar pressure and 50\u00b0C.\nThis technique preserves the pore structure of the gel, preventing collapse as commonly occurs during conventional drying methods.<\/p>\n\n\n\n
The result?\nThe surface area of freshly dried aerogel reached 1,975 m\u00b2\/g. In comparison, xerogel (gel dried through conventional methods) had only 272 m\u00b2\/g of surface area.\nThe difference was more than sevenfold.<\/p>\n\n\n\n
A large surface area alone is not sufficient. Newly dried TiO\u2082 remains amorphous, meaning its crystal structure has not yet developed properly. Electrons move with difficulty through amorphous materials, reducing solar cell performance.<\/p>\n\n\n\n
The research team therefore applied a multi-step calcination process: Heating at 150\u00b0C for 3 hours to evaporate solvents. Heating at 300\u00b0C for 3 hours to remove remaining organic compounds. Heating at 420\u00b0C for 2 hours to promote crystallization of TiO\u2082 into the anatase phase.\nThe first two stages were performed under an inert atmosphere (without oxygen), while the final stage was conducted in open air.<\/p>\n\n\n\n
This gradual approach proved significantly more effective than direct one-step calcination at 450\u00b0C.\nAfter multi-step calcination, the aerogel maintained a surface area of 72 m\u00b2\/g, slightly higher than xerogel, which retained 68 m\u00b2\/g.\nX-ray diffraction (XRD) analysis confirmed the formation of anatase crystals, with crystallite sizes of 9.21 nm in aerogel and 14.40 nm in xerogel.<\/p>\n\n\n\n
\u201cThe higher open-circuit voltage of DSSCs using TiO\u2082 aerogel was attributed to the larger surface area, which facilitated synergistic interactions between the sensitizing dye solution and the semiconductor material.\u201d<\/em><\/p>\n\n\n\n This was the conclusion presented by the research team, emphasizing that surface area is a major determining factor in DSSC performance.<\/p>\n\n\n\n Indonesia receives abundant solar radiation throughout the year, a natural resource that remains largely underutilized. DSSCs provide an alternative pathway that may be cheaper and easier to manufacture compared with conventional silicon solar cells because they do not require extremely sterile production environments.<\/p>\n\n\n\n Although this research only produced a prototype with a voltage level that remains low for large-scale applications, the achievement of TiO\u2082 aerogel in producing a Voc of 21.40 mV, far exceeding xerogel performance, demonstrates a clear direction for future development:\nSupercritical extraction combined with stepwise calcination represents a promising approach for further advancement.<\/p>\n\n\n\n The measured band-gap energy of the aerogel was 3.10 eV, slightly lower than bulk TiO\u2082 (3.20 eV). This indicates the presence of a quantum confinement effect caused by the extremely small crystal size.\nThis means the material may absorb light at slightly longer wavelengths, creating opportunities for broader solar spectrum utilization.<\/p>\n\n\n\n In a tropical country like Indonesia, where sunlight is available almost throughout the year, a material measured in nanometers may hold a promise far greater than its physical size.<\/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 Source DOI: https:\/\/doi.org\/10.4028\/www.scientific.net\/AMR.789.28<\/p>","protected":false},"excerpt":{"rendered":" Bayangkan sebuah material yang lebih ringan dari udara, namun mampu menangkap cahaya dan mengubahnya menjadi listrik. Itulah aerogel, dan tim peneliti dari Departemen Teknik Metalurgi dan Material Universitas Indonesia berhasil mensintesisnya dari titanium dioksida (TiO\u2082) menggunakan teknik ekstraksi superkritis CO\u2082. Penelitian yang dipublikasikan dalam Advanced Materials Research Vol. 789 (2013) ini dipimpin oleh Dr. drg. […]<\/p>\n","protected":false},"author":615,"featured_media":21189,"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-21178","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":"\nFrom Laboratory Research to Tropical Energy Dreams<\/h2>\n\n\n\n