Solar power technologies are the focus of voluminous research efforts, and now a team of scientists at the VTT Technical Research Centre of Finland Ltd. are developing a prototype 3D printed “tree” which also uses a novel gravure and screen printing process to collect solar energy.
The trees are capable of harvesting solar energy indoors or outdoors, storing it and creating enough electric power to run small devices such as mobile phones and LED lighting.
The VTT Technical Research Centre is the largest multi-technological applied research organization in Northern Europe and it’s a non-profit part of the Finnish innovation system under the domain of the Ministry of Employment and the Economy.
This came as a result of a new mass production method which enables designers to create fun
ctional objects from organic solar panels – or OPV, organic photovoltaics – which are sensitive enough to collect energy from interior lighting or sunlight.
The ultra-thin solar panels are around 0.2 mm thick, and they include electrodes and polymer layers along with graphics which provide them with visual appeal.
The team at VTT printed the leaf-shaped photovoltaic cells, each of which has a surface area of 0.0144 square meters and includes connections and the necessary wiring, and they say 200 of the OPV “leaves” can generate 3.2 amperes of electricity and 10.4 watts of power outdoors in sunnier climes in a one-square-meter formation.
Flexible, very light, and considerably lower in efficiency than rigid, silicon-based solar panels, the “leaves” are manufactured using a roll-to-roll method capable of producing up to 100 meters of layered film per minute.
Each “leaf” is affordable and consumes very little raw material. Once the working life of the leaves – likely a few years – is over, the OPV panels can be recycled.
VTT is also developing roll-to-roll manufacturing methods which use inorganic perovskite solar panels which may well open new applications for printable solar cells. The research work with 
methylammonium lead tri-iodide, derived from the crystal perovskites, offers a great deal of promise as well. Materials scientist Yang Yang at the University of California, Los Angeles, has built a solar collection cell from it which achieved more than 19% efficiency. That output rivals crystalline silicon solar cells which can currently achieve 17-23% efficiency.
“I don’t know any group that works on photovoltaics that isn’t looking at perovskites,” says Henry Snaith, a physicist at the University of Oxford.
The “leaves” of the tree, attached to 3D printed “trunks” made of a wood-based biomaterial also developed at VTT, are flexible and patterned to form an electronic system complete with wiring channels that conduct energy to a converter system.
Have you used 3D printing to create any solar powered devices? Let us know in the Electric Forest With 3D Printed Trees forum thread on 3DPB.com.
