太陽能板不再只能鋪設在住宅屋頂上發電，還能用於室內裝潢！芬蘭科技研究中心（Valtion Teknillinen Tutkimuskeskus，VTT）研發出可撓式有機太陽能板，有別於傳統太陽能板質地堅硬、且色調單一，VTT 的新型太陽能板不僅可彎曲，還可在上頭印製不同顏色與圖案，成為兼具發電與美觀的裝潢材料。
該有機太陽能板採用捲軸式製程，可大量且快速生產，每分鐘約可生產 100 公尺的壓印材料。VTT 研究團隊表示，材料的其中 1 層在塑膠底上採用旋轉式網版印刷（Screen Printing），另外 2 層以凹版印刷壓印，具蓄電功能的太陽能電池層則是夾在塑膠層中間。
研究人員在測試時，印製了 200 個葉片形狀的太陽能電池，組成 1 平方公尺的太陽能板，一共產生 10.4 瓦特的電力輸出，電流則為 3.2 安培。
VTT 所研發出的可撓式有機太陽能板厚度僅 0.2 釐米，內含電極及能收集太陽能的多層聚合物。可鋪設在室內或戶外的牆壁、窗戶、機器及裝置上，供應電燈等小型家電所需電力。
作者 林 薏茹 |21/01/2015
VTT Technical Research Centre of Finland Ltd has developed and utilized a mass production method based on printing technologies allowing the manufacturing of decorative, organic solar panels. Design freedom improves the range of applications of the panels on the surfaces of interior and exterior building spaces. VTT is also studying the feasibility of printing technology in the mass production of solar panels made from inorganic perovskite materials.
The new mass production method enables to create interior design elements from organic solar panels (OPV, organic photovoltaics) harvesting energy from interior lighting or sunlight for various small devices and sensors that gather information from the environment. The panels can, for example, be placed on windows and walls and on machines, devices and advertisement billboards. Until now, it has only been possible to pattern OPV panels into a form of stripes.
The solar panel manufactured with VTT's gravure and screen printing technologies is only around 0.2 mm thick, and includes the electrodes and polymer layers where the light is collected. Furthermore, graphics can be printed to improve its visual appearance.
VTT has proven the feasibility of the method in its own pilot manufacturing unit, using commercially available materials. VTT is commercialising this manufacturing technology with different operators, and is actively seeking new final-stage appliers of the technology.
The research scientists have tested the feasibility of the method by printing leaf-shaped photovoltaic cells. Active surface of a one leaf is 0.0144 m2 and includes connections and a decorative part. Two hundred OPV leaves make one square metre of active solar panel surface that generates 3.2 amperes of electricity with 10.4 watts of power at Mediterranean latitudes.
Flexible OPV cells
Organic solar panels are flexible and light, but their efficiency is lower compared to conventional, rigid silicon-based solar panels. The solar panels are manufactured with printing machines based on conventional printing methods using the roll-to-roll method, which enables the rapid mass production of the products: the printing machine can produce up to 100 metres of layered film per minute. The manufacturing of the OPV cells is affordable; the material consumption is low, and after use, the OPV panels can be recycled.
The market for organic photovoltaic cells is developing, with a market breakthrough expected within three years. The operating life of panel is few years which is enough for many applications.
VTT is developing roll-to-roll manufacturing methods for inorganic perovskite solar panels
VTT is also currently examining how well the roll-to-roll printing methods are suited to the manufacturing of inorganic solar panels made from perovskite materials. The first perovskite solar cells manufactured in the laboratory using solution-based processes have been promising. The performance of this solar cell is roughly five times better than that of an organic photovoltaic cell, and the material costs can be even ten times lower.
Freely designed decorative organic solar panels are applicable also in indoor use to harvest energy from indoor light. Production methods are cost-effective and materials can be recycled after the use. New materials such as perovskite can be printed with same methods and increase efficiency in future.
Using energy of light in data transfer
VTT is also developing a method to utilize light in wireless data transfer by using solar cells as data receivers. This will open new application possibilities to utilize printable solar cells e.g. in IoT (Internet of Things) type applications, in which the devices can also harvest energy from the ambient light. The first results have been very promising.