We’ve said it before, and we’ll say it again. 2015 is going to be a huge year for the solar industry. A photovoltaic system is installed every four minutes in the US. There are now 142,000 jobs in the solar industry alone. Some experts are even saying that rooftop solar will reach grid parity in all 50 states by 2016.

The research behind solar energy is booming, too. Scientists are discovering new ways to decrease costs and increase efficiency of solar panels and coming up with creative, impressive ways to generate power. Here are eight examples.

1. Bionic leaf

Scientists at Harvard recently created a bionic leaf, which uses a catalyst to make sunlight split water into hydrogen and oxygen, then a bacteria engineered to convert carbon dioxide and hydrogen into a liquid fuel called isopropanol. They’re almost at a 1% efficiency rate of turning the sunlight into the fuel — in other words, they’ve found a way to recreate the efficiency of photosynthesis.

2. 3D printed solar powered trees

Researchers at the VTT Technical Research Centre of Finland created a solar powered electric forest with 3D printed trees. That’s quite a bit of buzzworthy tech in one project. The trunk of the trees are made from 3D printed wood biomaterials, and the leaves are the solar “panels.” They are much less efficient than traditional PV panels, but the research they’re doing for solar cells is promising as well.

3. Perovskites

Perovskites are materials with a specific crystalline structure. Stanford University researchers found that using lead, ammonia, and iodine, they could make a lot of it for cheap. Perovskites are more efficient than silicon in some ways, so the idea is using them to supplement rather than replace silicon may be a way to increase the efficiency of solar cells. At Stanford, a silicon solar cell with an efficiency of 11.4% increased to 17% with perovskite.

4. Thin film solar

New research from Cornell, published in Nature in January, showed that scientists are reporting better solar cells by changing the chemistry of the materials. Thin film solar, which is a photovoltaic material onto a substrate like silicon. The ones made by these researchers at Cornell are organic-inorganic metal halide perovskites, which the team has been studying for a while. The new solar cells use a liquid source and a simple coating, which can make it appealing for more commercial uses.

5. Carbon-based solar cells

Another cheap alternative to silicon that has emerged is printed carbon-based, or organic, solar cells. The efficiency is still relatively low compared to other materials, and the research surrounding it peaked about a decade ago. But, as perovskites gain popularity in reducing the cost and increasing efficiency of cells, carbon-based options are looking like contenders, too.

6. Colored solar panels

Scientists have found a way to make solar panels a little more aesthetically pleasing. They layered silicon dioxide, often used to make glass optical fibers, and titanium dioxide, used to absorb UV rays, to make a photonic crystal structure that can absorb sunlight. Colors appear when light is reflected and absorbed, and the colors change depending on the thickness of the materials.

The problem is, these panels are much less efficient than black solar panels, only reaching up to 9%. The blue, for instance, is only about 6%. The hope is that as the technology advances, the efficiency will increase — but for now, it’s a way to possibly mainstream the idea of solar even more.

7. Polymer solar cells

Polymer solar cells, called P1D2, may increase solar cell efficiency. The research comes from the University of Chicago’s chemistry department, the Institute for Molecular Engineering, and Argonne National Laboratory. The polymer breaks down easier and allows more electrons to travel faster. The researchers said in a test, it increased solar cell efficiency by 15%.

8. Solar concentration technology

Concentrating photovoltaic (CPV) systems are giant and have to be angled very accurately to get the right amount of sun during the day. They work great, but they’re not ideal for roofs. Now, a team of researchers is working on using that high-efficiency technology for rooftop PV systems by building them with miniaturized, gallium arsenide photovoltaic cells and 3D printed plastic lens arrays. The systems weigh less, cost less, and are much smaller than CPV systems, though, and can be optimized for rooftops.

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