Picture a world where our windows could be part of the power grid. The first energy-producing window has come to America, being a shining example that even something that is colorless and flexible can produce energy while being powered by novel transparent solar cells (TSCs). We have entered the era of photovoltaics, as now windows not only allow light to seep through but turn the sun’s energy into electricity. Power can be generated through windows that are not in any way distorted or tinted, as were the earlier solar window prototypes. If an aesthetically pleasing solar power option is available, everyone is all for it. More so if it can live up to its promise of being attractive and efficient.
Energy-producing windows: A ray of hope and sunshine
While this may not be the very first energy-producing window, it is one of the first transparent energy-producing windows. Older TSCs that sought to achieve similar results focused on organic materials, dyes, or perovskites. While power conversion was no setback, the setback was the fact that they were of a tinted transparency, which was not at all as visually appealing when used for cars and office buildings. The brownish colored tint that was inevitable due to the materials used to create these windows made these solar windows a less attractive option.
In terms of this flaw, the Ulsan National Institute of Science and Technology (UNIST) was able to overcome this flaw. Rather than making use of films capable of absorbing only certain wavelengths, the UNIST team was able to utilize n-type silicon microwires in the form of a flexible yet transparent polymer sheet. By doing this, the microwires became hard to see due to the lack of clarity of the polymer matrix. UNIST accomplished an incredible feat by creating a window that looks like glass but is capable of harnessing energy from the sun.
A bonus was the slanted tip appearance of microwires, which is able to absorb light better. In actuality, this arrangement led to 8,07% PCE at 10% visible transparency, which is record-breaking for silicon-based TSCs
How did UNIST succeed whilst ensuring solar efficiency?
While we said goodbye to solar panels a long time ago and paved the way for the concept of our windows producing energy, the main difference of these solar-producing energy windows is the way they were meticulously engineered.
The wet etching method was enabled through the use of deep-reactive ion etching and a solvent. It was the silicon microwires that got the most attention and were created with precise spacing and slanted tips. This was done to ensure that the microwires acted as the photoactive layer, transforming sunlight into electricity.
Maximal charge is ensured by the heterojunction between the p-type polymer on top and the n-type silicon. The sides are further protected by an Al₂O₃ passivation layer, which makes these windows more durable. The researchers were able to accomplish a creation where reflected light is redirected rather than lost.
Stretchability is an added feature that makes these windows so attractive. The future of energy is surely in these transparent windowpanes.
Not as transparent is the road ahead for these solar windows
The promise offered by these solar windows is that offices and vehicles can contribute to generating power without even showing signs of this power generation in progress. For this promising energy-generating possibility, we have silicon to thank. Silicon is a stable material and is readily available, which reduces any setbacks for long-term stability. Silicon also vows to have no environmental impact.
Perhaps it’s becoming more transparent that buildings will now generate energy and no longer simply consume energy, and at the same time, buildings will still look normal while doing so. By transforming your understanding of what photovoltaics is, you can bring forward the possibility of harnessing infinite energy from your windows.
