Perovskite Solar Cells: A New Powerhouse for Home Electricity Generation?

1. The Unique Charm of Perovskite Cells

Perovskite solar cells are batteries that use perovskite-type crystals as the light-absorbing layer material, and their working principle is based on the photovoltaic effect. When sunlight shines on perovskite materials, it excites the formation of hole-electron pairs, which are transported to the cathode and anode respectively, forming an electric current.

Perovskite solar cells have many unique advantages. Firstly, they have high photovoltaic conversion efficiency; the current record for single-junction perovskite cell efficiency is 26.1%, set by the University of Science and Technology of China in July 2023. In terms of tandem cells, in November 2023, Longi Green Energy’s independently developed monocrystalline silicon-perovskite tandem cell efficiency was certified by NERL to reach 33.9%, the highest record for global monocrystalline silicon-perovskite tandem cell efficiency to date. Secondly, they are low-cost and easy to prepare; most perovskite cells use solvent processes, with raw materials mostly in liquid form, allowing for preparation at room temperature. In the future, printing technology can be used to prepare large-area flexible solar cells and for wearable smart devices. Additionally, perovskite materials have a high weak light effect, working in weak light environments such as overcast weather and dawn and dusk.

The perovskite cell industry is currently at an important stage of transitioning from the laboratory to industrialization. In 2023, the new capacity of perovskite cells in China is about 0.5GW, mainly from the successful completion and production of Ren Chao Photoenergy’s 150MW perovskite photovoltaic component project and the landing of Wandu Photoenergy’s 200MW class printable meso-perovskite solar cell pilot line and other project productions. Perovskite cells have reached a key point in commercialization, with a penetration rate of about 0.2% in China’s perovskite pool in 2023. With continuous technological improvements, the penetration rate of perovskite cells in China is expected to grow in the future.

The application prospects for perovskite cells are broad, with competitiveness in the distributed photovoltaic market, and can be widely used in fields such as BIPV facades and photovoltaic roofs. At the same time, the tunable bandgap of perovskite solar cells makes it an ideal broad bandgap for indoor photovoltaic cells, which can be extended to weak light and indoor photovoltaics, applied in fields such as industrial Internet of Things, smart homes, and smart travel. Relevant companies have already laid out research in this application field. Certified by the National Photovoltaic Industry Measurement and Test Center, the photovoltaic conversion efficiency of perovskite indoor photovoltaic cells developed by Guangdong Mai Luo Energy Technology Co., Ltd. reached 44.72% under the illumination of 1000luxU30 light source.

1. New Possibilities for Home Electricity Generation

(1) Impressive Energy Output

A case study of BIPV application of perovskite solar cells on a single-family home near Poznan, Poland, showed surprising energy output results. The home has an area of 92.8 square meters, and it is calculated that the annual energy output provided by the east-west roof alone is 12,377.95 kWh, which exceeds the average annual electricity consumption of a family of four. If all possible areas that can be covered by perovskite solar components are considered, such as walls (26,816.48 kWh) and windows (2,064.15 kWh), the total annual energy output is 41,258.58 kWh. This means that perovskite solar cells can not only meet the energy needs of a single house but also support the electricity needs of three other families.

(2) Technological Innovations Aid

New perovskite manufacturing technologies continue to emerge, laying the foundation for large-scale production and popularization in homes. For example, a Chinese research team has innovated the preparation process of perovskite photovoltaic materials, using a multifunctional ionic liquid as a solvent to replace traditional toxic organic solvents, with the advantages of high stability and simple preparation process. In addition, Phenomenal Photovoltaics has innovated the composition of perovskite precursor solutions from the perspective of simplifying cell structure, achieving photovoltaic conversion efficiencies of 25.9% and 21% on extremely small areas and large-area modules, respectively, greatly optimizing the preparation process of perovskite photovoltaic cells. At the same time, there are also studies that enhance the performance of perovskite solar cells by using antisolvents and caffeine, etc. Antisolvents can improve the crystallization quality of perovskite films, enhancing the stability and efficiency of the cells. Caffeine can be used as an additive to regulate the growth of perovskite crystals and improve photovoltaic conversion efficiency.

(3) Changing Urban Power Generation Systems

The technology of semi-transparent solar cells that can be embedded in windows has brought huge potential impact on buildings, urban planning, and power generation. Australian scientists have created a new generation of perovskite solar cells that can generate electricity while allowing light to pass through. This semi-transparent cell has a conversion efficiency of 17%, but it can still transmit more than 10% of the incident light. The electricity generated by a solar window of two square meters is equivalent to that of a standard rooftop solar panel. This technology will transform windows into active power generators and may bring revolutionary changes to architectural design. Planners and designers may even have to reconsider how to arrange buildings on the site to optimize the way walls absorb sunlight.

(4) Prospects for Building Integration

Perovskite solar cells are expected to achieve building integration, with many advantages. Perovskite solar cells have the characteristics of high efficiency and adjustable transparency, providing more possibilities for architectural design. Their color diversity also makes the appearance of buildings more diverse. At the same time, perovskite cells are light in weight and flexible, facilitating installation on curved surfaces of buildings, providing new ideas for architectural aesthetic design. However, the long-term stability of perovskite solar cells is key to commercial application and requires further technological breakthroughs. Currently, to improve the stability of perovskite solar cells, in addition to replacing material components or chemical modification to inherently improve its moisture resistance, the most common methods are to use encapsulation protection and hydrophobic electrodes to prevent moisture erosion of the device. In addition, finding an effective method to suppress ion migration has become key to solving the stability problems of perovskite materials and devices. It is believed that with technological maturity and market recognition, the application prospects of perovskite solar cells in the field of building integration are broad.

III. Future Outlook

(1) Huge Potential

Perovskite solar cells have huge potential in promoting the popularization of home solar power generation systems. Firstly, their high photovoltaic conversion efficiency means that a large amount of electricity can be generated in a relatively small area, meeting the electricity needs of households. For example, the single-junction conversion efficiency of perovskite solar cells has already reached a high level, and with continuous technological progress, the efficiency is expected to be further improved in the future. Secondly, the tunability of perovskite materials allows solar cells to be customized according to different architectural needs, whether in color, transparency, or shape, they can be perfectly integrated with architectural design. In addition, the preparation process of perovskite solar cells is relatively simple, and the cost is low, which provides the possibility for large-scale production and application. According to statistics, the manufacturing cost of perovskite solar cells is only about half of that of traditional silicon-based solar cells, and with technological maturity and the expansion of mass production scale, the cost is expected to be further reduced.

(2) Challenges Remain

However, perovskite solar cells also face some challenges in popularizing home solar power generation systems. Firstly, stability issues remain a key factor restricting their development. Perovskite materials are extremely sensitive to water, heat, and oxygen environments, which can easily lead to structural instability, thereby reducing the performance and life of the cells. At present, although there are some methods that can improve the stability of perovskite solar cells, such as encapsulation protection, hydrophobic electrodes, and chemical modification, these methods still need further optimization and improvement. Secondly, the lead and other toxic elements in perovskite solar cells have also attracted people’s attention. Although lead-free perovskite materials are being studied, their performance and stability still need to be improved. In addition, the standardization and specification of perovskite solar cells is also an important issue. As perovskite solar cells are a new technology, there are currently no unified standards and specifications, which brings certain difficulties to product quality control and market promotion.

(3) Future Outlook

Despite some challenges, the prospects for perovskite solar cells in promoting the popularization of home solar power generation systems remain broad. With continuous technological progress, it is believed that stability issues and toxic element issues will be effectively resolved. At the same time, the formulation of standardization and specification will also provide strong protection for the market promotion of perovskite solar cells. In the future, perovskite solar cells are expected to become the mainstream choice for home solar power generation systems and make an important contribution to the realization of sustainable energy development. We can look forward to