Applied Technology

Novel Nanostructured Coatings for Solar Cell Modules

On Dec. 25, 2012, a project entitled “Self-cleaning antireflective nanostructured coatings and their application in solar cell modules”, which was untaken by the Technical Institute of Physics and Chemistry, CAS, has passed check-acceptance. The project team, led by Prof. He Junhui, studied the regulation of surface wettability and light transmission by constructing novel nanostructures. They unveiled the mechanism and design strategy of self-cleaning broad-band antireflective nanostructured coatings, developed approaches to assembly/fabrication of self-cleaning antireflective hierarchically nanostructured coatings. The team has eventually realized both superhydrophilic and superhydrophobic self-cleaning functions on transparent substrates such as glasses, including solar cell module glass panels. The new technology promises great potentials for industrial applications.

Improvement of Novel Photovoltaic Materials

Recently, Prof. Huang Fuqiang's group (Photoelectric Conversion Research Group, Shanghai Institute of Ceramics), in collaboration with the Chemistry Department of Peking University, obtained important progress in the novel photovoltaic materials. The team successfully introduced a partially filled intermediate band to the forbidden band gap by doping Sn at the site of In/Ga in CuInS2 and CuGaS2, which are chalcopyrite-type solar cell materials (Sn doping in CuGaS2 reduces the band gap to 1.8 eV but extends the absorption to the infrared region of 1.0 eV, and Sn doping in CuInS2 reduces the band gap to about 1.0 eV). Such intermediate band acts as a springboard for the transition of the photons with small energy, and thus the restrictions of the optical band gap of the material in response to the solar spectrum were eliminated, and three electron transition channels excited by photons (VBM ? CBM, VBM ? IB, IB ? CBM) are realized. Thus, the response to most of the solar energy spectrum is available and the photocurrent can be apparently increased, which laid a base for the sharp increase of the conversion rate of the solar cells. With the strategy of adjusting the coordination of central ions to realize the reduction of the band gap (Eg), the team developed a new type narrow-band-gap ferroelectric photovoltaic material with a tetrahedral coordination framework, KBiFe2O5. Compared to octahedral coordination, tetrahedral coordination possesses smaller crystal field splitting energy which could effectively decrease the Eg. The photovoltaic performance of this sample is superior to the known optimal ferroelectric photovoltaic materials. Relevant results have already been published on Scientific reports (2013, 3, 1265；2013, 3, 1286) by the Nature Publishing Group (NPG).

Fire-Resistant Hydroxyapatite Paper Invented

Recently, the research team led by Prof. Zhu Yingjie of the Shanghai Institute of Ceramics, CAS has conducted research on hydroxyapatite nanostructured materials with controllable structure, size and morphology, and they have developed a new method for the synthesis of hydroxyapatite ultra long nanowires with adjustable ydrophilicity/hydrophobicity using calcium oleate as a precursor. By using hydroxyapatite ultralong nanowires as the building material, a new kind of highly flexible and fire-resistant hydroxyapatite paper has been developed by a simple vacuum filtration technology. The as-prepared paper has a high flexibility; it is bendable, nonflammable, and high-temperature-resistant. At present, the preparation of this highly flexible and fire-resistant paper is still limited to the laboratory scale, and the research team is working towards the direction of low-cost and large-scale production. This work was published in Chemistry-A European Journal 20, 1242 (2014), and it was also reported by international magazines such as Materials Today, the American Ceramic Society, ChemViews Magzine, Decoded Science, Materialy Inzynierskie