JST New Technology Presentation Meeting
Efficiency of Sn series perovskite solar cell is enhanced by Ge ion doping

May 28th, JST New Technology Presentation Meetings was held by online method. In this here, oral presentation by Prof.Hayase of The University of Electro-Communications is picked up.

As you know, Pb series device has been mainly developed in the perovskite solar cell, however, considering environmental problem, Pb-free device instead of Pb series device is ideal. Its strong candidate is a Sn series device using Sn²⁺ perovskite. In principal, if crystal structure is perfect, incident photon-to-current efficiency (IPCE) of the device is almost same as that of Pb series device. However, in fact, its IPCE is greatly lower than that of Pb series device because of crystal defect and influence of impurities.

Therefore, the research group of The University of Electro-Communications succeeded to suppress influence of their defects by doping Ge ion into Sn perovskite layer, as a result, to increase IPCE from 5 % to 13.2 %.

Performance of PV device is greatly enhanced by full-encapsulation using cylindrical glass tube

Furthermore, the research group devised a cylindrical form device, in order to make use of flexible advantage of perovskite solar cell. Figure 1 shows its structure. First of all, a perovskite device is manufactured on a plastic film, and then, it is inserted into cylindrical glass tube, finally its both ends are encapsulated. In short, its structure is almost same as that of the fluorescent lamp.
Compared to the conventional flat device using two encapsulated films, there are some advantages, �@Light weight (4.2kg/m²), �AStable to wind and snow, �BSetting flame is light because of light solar cell, �CSetting cost is inexpensive. In fact, output of 90 × 100 cm Sn²⁺ device is 180 W, which is practical value.

Fig.2 Comparison of output per day

図Fig.1 Flat flexible device and cylindrical form device

And also, as figure 2, total output of the cylindrical device is 1.5 times compared to than that of the flat device. This is reason why angle dependency against solar light of the cylindrical device is smaller than that of the flexible device.