The research group of Professor Michael Gratzel of EPFL, the University of Oxford and the Yokohama University of Japan have independently developed a conversion efficiency of more than 15%. Solid-type dye-sensitized solar cells (DSSC). In about half a year, the conversion efficiency has increased by about 4 percentage points, greatly surpassing other organic solar cells (Figure 1). This DSSC uses a perovskite-phase organic-inorganic mixed crystal material CH3NH3PbI3 as a dye-sensitized material and a hole-transporting material (HTM) composed of an organic material in place of the electrolyte ( FIG. 2 ). The DSSC developed by the Federal Institute of Technology in Lausanne consists of glass, FTO, TiO2, CH3NH3PbI3, HTM and Au. The DSSC developed by Oxford University and others also uses aluminum (Al2O3) together with TiO2. As a solar cell made of organic materials and inorganic materials, both have achieved conversion efficiencies comparable to crystalline silicon solar cells for the first time. Use solid electrolytes to dramatically increase conversion efficiency The predecessor of the DSSC with this structure was a solar cell proposed by the research team of Professor Yosuke Miyako of the University of Yokohama, Japan in April 2009. At that time, many people tried to use quantum dots as sensitizers to fabricate quantum dot sensitized solar cells. Miyazaki pointed out that "quantum dots have low efficiency and there are many problems such as the reverse flow of current." Therefore, we turned our attention to CH3NH3PbI3. CH3NH3PbI3 not only efficiently absorbs broad-spectrum light from visible light to 800 nm in wavelength, but also has the feature of being directly chemically synthesized on porous materials such as TiO2. Ideal for coating processes. However, Miyazaki et al. used a traditional DSSC electrolyte during trial production in 2009, and the conversion efficiency was only 3.8%. Later, in 2012, researchers at the University of Oxford in Miyagaki Research Laboratory replaced the electrolyte with a "spirodioxime compound" that was generally used as a solid DSSC HTM. As a result, the conversion efficiency exceeded 10% for the first time, reaching 10.9%. Later, as the process was continuously optimized, the conversion efficiency jumped to 15.36% in only about six months. Future conversion efficiency may reach 21% Although this technology is based on DSSC, "someone pointed out that this is not DSSC" (Miyaji). Because of the material, component composition, and power generation principles, it has many characteristics similar to organic thin film solar cells and inorganic compounds CIGS (CuInGaSe) type solar cells (Fig. 3). Just because of the similarity, if it does not go beyond the original solar cell, its mixed material significance is not big, and the new solar cell has already surpassed the original DSSC and the organic thin film solar cell in the conversion efficiency. And, it is said that in the future it is possible to exceed the CIGS solar cell. The conversion efficiency of CIGS solar cells is currently at the highest of 20.4%, and Miyaji expressed that “this solar cell adopts current materials and technologies, and the conversion efficiency can reach 17%. In the future, it can reach 21%.†In addition, unlike solar CIGS solar cells, new solar cells do not use heavy metals such as indium (In) and gallium (Ga) and rare metals, and can be manufactured with very low cost materials. And, at the beginning, it was developed using a coating process, which is also a big advantage. On the other hand, there are still two major issues for new solar cells. One is that the current organic-inorganic hybrid material contains lead (Pb), which is harmful to the human body, although it has a low cost. Recently, attempts have been made to substitute tin (Sn) and copper (Cu) for lead. Another subject is the difference in component characteristics. Miyaji said that "some trials have conversion efficiency of about 11%, and some trials can only reach 5%." However, it is said that this can be solved by optimizing the manufacturing process in the future. In fact, the research team of Granzel et al. adopted a two-stage coating process to form CH3NH3PbI3, which not only achieved high conversion efficiency, but also drastically improved the characteristic differences. (Reporter: Nozawa Tetsuru, Nikkei Electronics) Smart Water Meter,Smart Home Water Meter,Smart Water Flow Meter,Residential Smart Water Meter Shandong Chenshuo Meter Co., Ltd. , https://www.chenshuometer.com
Figure 1: Far beyond other solar cells 
Fig. 2: Realization using materials with high light absorption rate 
Figure 3: Overlapping with Organic Thin Film Solar Cells
Dye-sensitized solar cells have dramatically increased conversion efficiency by 15%