New Technology Presentation Meetings!-Green Nano Technology
Washable ultra-thin type organic solar cell has been proposed

December 21, 2017, “New Technology Presentation Meetings!-Green Nano Technology” was held in JST. In this here, oral presentation by Fukuda of Riken is picked up.

Main aim of this R & D is to develop a thin film solar cell with water stability. It is required for outdoor use and wearable applications. Same as clothes, an ideal wearable solar cell is completed by washing in house repeatability. However, a device with ultra-thin type and water stability property has not been reported yet. As you can image, if device become to be thinner, gas barrier property of device is degraded.

Figure 1 shows structure and manufacturing process of prototype. Solar device is manufactured on the support glass substrate, and then, it is released from fluoro polymer release layer, as a result, a flexible device is completed. In short, CVD-deposited thin film polyparaxylene film (t = 1 μm) is used as a device substrate.

Figure 1. Structure and manufacturing process of organic film solar cell1)

Figure 2. Peel-off test result1)

Figure 2 shows test result of peel-off from the support glass substrate. Incident photon-to-current efficiency (IPCE) of the device was merely reduced from 8 % to 7.9 % after peel-off. In short, if device was peeled off, device property was not almost changed. On the other hand, as figure 3, atmospheric stability was relatively high. After 30 days, solar cell was stably operated.

As figure 4, above device was sandwiched by two transparent acrylic rubbers (t = 500 μm), to grant water stability. In this rubber sandwiched structure, stretchable property was not reduced compared to that of the initial device (without rubbers).

Figure 3. Comparison of atmospheric stability1)

Figure 4. Sandwich structure using rubber1)

Figure 5 shows estimate result of water stability by dipping this rubber sandwiched device into DI water. Water stability was greatly enhanced by rubber sandwiched structure; as a result, IPCE was not almost changed after 120 minutes. Furthermore, black ink was adhered to surface of the device by intent, and then, its device property was estimated. As a result, it was eliminated on the device by washing with a cleanser; ICPE of the device was recovered to the initial value. In short, if the device is washed repeatability, device property is not changed.

Reference
1)Fukuda：Washable ultra-thin type organic solar cell, New Technology Presentation Meetings!-Green Nano Technology, pp.3-7 (2017.12)

※This title is translated arbitrarily by Stella News Site because of without English edition of presentation material.