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Squeezing out more juice – Innovations for improving solar panel efficiency

The solar industry has come a remarkably long way in recent decades. Since the first photovoltaic modules emerged in the 1950s, solar technology has progressed by leaps and bounds. Today’s solar panels are drastically more powerful and reliable than their predecessors.

Refining silicon solar cells

The photovoltaic market has long been dominated by first-generation silicon solar cells, which have capped out at around 22% efficiency to date. This conversion rate refers to what percentage of the sun’s photons hitting the solar cell get converted into usable electrical current. Recently, more advanced silicon cell prototypes from manufacturers like Panasonic have exceeded 25% efficiency in laboratory testing. This efficiency edge comes from implementing more sophisticated device architectures, smarter optical enhancement coatings, and quality-control improvements during fabrication. As these enhanced silicon production techniques grow more cost-effective, conventional solar tech is poised to take another big jump.

Thinner wafers and bigger returns

As manufacturers have scaled up production, they’ve also managed to slim down the wafers to around 150 microns or less compared to the 300+ micron standard a decade ago. These thinner silicon slices reduce internal electrical resistance and allow better light absorption across the cell. When paired with higher-purity silicon, wafer thinning enables efficiency improvements. Expect even thinner wafers moving forward, especially as automated production brings down costs. However, handling such delicate substrates without breakage becomes an escalating challenge.

Prospecting with perovskites

This emerging PV technology relies on a class of materials with a perovskite crystal structure, like methyl ammonium lead halides. Not only are perovskite-based solar cells projected to reach higher conversion efficiencies than silicon, but they should also be much cheaper and simpler to produce at scale. Recent perovskite solar prototypes have sailed past 25% efficiency in the lab, some even flirting with 30% conversion rates. Early real-world testing of perovskite cells in modules indicates they maintain 85% of their peak efficiency after thousands of hours of operation. There are still unanswered questions around toxicity and stability left to address before perovskites hit the mainstream. But the fundamentals appear robust enough to shake up the solar panel efficiency
landscape in the next 5-10 years if development stays on track.

Squeezing out more juice with multi-junctions

Thus far, you have focused on innovations targeting single-junction solar cells made of one light-absorbing material like silicon or perovskites. But stacking different materials together into multi-junction solar cells also pays big efficiency dividends. With this approach, each junction absorbs a separate slice of the solar spectrum, making better use of all available wavelengths. Multi-junction solar cells based on gallium arsenide and related semiconductors currently dominate the efficiency leaderboards, hitting demonstrated conversion rates of over 45%. Their triplicate cost keeps them restricted to niche applications like satellites and spacecraft for now. However, introducing cheaper materials like perovskites into these layered multi-junction designs offers a path to efficiency ratings above 50%. Better solar spectrum splitting and light management will help push the limits too. Even in standard panels, you soon see dual-junction cells hitting 30%+ efficiency if research continues progressing favorably.