Combined with silicon perovskites technology, the conversion efficiency of solar cells jumped to 27.2%

• Solar energy technology is changing with each passing day. The record of photoelectric conversion efficiency will be renewed every few weeks. For example, Oxford PV, a British solar company, recently improved the efficiency to 27.2% through the perovskite silicon solar energy technology. Silicon solar energy is the preferred technology in the current industry. The advantages of low cost, high efficiency and stability make solar photovoltaic the most popular renewable energy. However, for the technology that has been commercialized on a large scale.

  
  

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• Solar energy technology is changing with each passing day. The record of photoelectric conversion efficiency will be renewed every few weeks. For example, Oxford PV, a British solar company, recently improved the efficiency to 27.2% through the perovskite silicon solar energy technology. Silicon solar energy is the preferred technology in the current industry. The advantages of low cost, high efficiency and stability make solar photovoltaic the most popular renewable energy. However, for the technology that has been commercialized on a large scale, its conversion efficiency is expected to be difficult to exceed 25%. Therefore, scientists have been looking for another solar energy star. Perovskite is a rising star in the field of solar energy. The photoelectric conversion efficiency has increased to 22% comparable to that of silicon solar energy in 9 years. In recent years, in order to seek breakthroughs and new materials, scientists have combined perovskite with silicon solar energy one after another, making the solar cell materials that were originally in the market competition make peace and create new solar cells. Oxford PV in the United Kingdom has successfully developed a 1cm2 high efficiency perovskite silicon solar cell based on this technology. In addition to obtaining the certification of the Fraunhofer Institute of Solar Systems (ISE) in Germany, this efficiency has also broken the 26.7% record of single junction silicon solar cells.
  

  
  

• The company does not expect to maximize the efficiency of a single solar material. Instead, it tries to increase the conversion efficiency of perovskite silicon solar cells to more than 30% by taking advantage of their respective advantages and disadvantages and different energy gap characteristics. Theoretically, because the energy gap widths of perovskite and silicon crystal materials are different, their light absorption ranges do not overlap, so they can perform their respective duties: perovskite is responsible for absorbing green light and blue light and converting them into electrical energy, while silicon is used to absorb red light and near-infrared light, but the reality is often not so simple.

  
  

  The band gap overlap effect still cuts the efficiency of the bottom layer silicon solar cell in half, greatly affecting the overall solar efficiency. In order to develop efficient perovskite silicon solar cells, the company combined 17% and 22% of the conversion efficiency of perovskite silicon solar cells. However, due to the energy gap overlap effect, the final conversion efficiency is about 11% less than expected. However, compared with ordinary silicon crystal and perovskite batteries, the conversion efficiency of 27.2% is a breakthrough in the industry. Oxford PV is also currently trying to produce 156mmx156mm commercial size perovskite silicon solar cells in Germany, and is trying to sell its concept. Frank Averdung, CEO of Oxford PV, pointed out that the company's biggest challenge at present is not to improve the conversion efficiency, but to stabilize its performance. Perovskite made of methyl amino lead iodide (MAPbI3) will decline when encountering humidity. The company hopes to make breakthroughs one by one, and hopes to put it into testing in 2019 and launch its products in 2020. OxfordPV is not the first team in the world to develop perovskite silicon solar cells. In February 2018, Brown University and the University of Nebraska Lincoln (UNL) in the United States had developed this technology in full swing, and they also wanted to develop lead-free perovskite batteries; The team composed of the Federal Institute of Technology (EPFL) in Lausanne, Switzerland, and the Swiss Center for Electronics and Microtechnology (CSEM) also raised the conversion efficiency of this type of battery to 25.2% in the middle of this month, and perhaps the industry and research institutes will reach 30% efficiency in the near future.