Toshiba's transparent Cu2O tandem solar leading cell accomplishes 8.4% efficiency

• Toshiba Corporation today introduced that it has successfully raised the power conversion effectiveness (PCE) of its transparent Cu2O solar cell to 8.4 percent, the world's highest degree for a reported Cu2O solar cell.

With the cell positioned as the top cell over a 25 percent PCE silicon cell (Cu2O-Si tandem cell), Toshiba estimates that a general PCE of 27.4 percent can be achieved, especially above the 26.7 percent highest PCE reported for any basic silicon cell.

Under the test criteria specified by Japan's New Energy and Industry Technology Development Organization (NEDO), Toshiba estimates that the Cu2O-Si tandem cell will lug an EV 35km without any need of recharging. Looking in advance, Toshiba expects the brand-new cell to boost development of EVs without any requirement for plug-in charging, and to progress various other wheelchair applications, such as the High Altitude Platform (HAPS), the telecom platform in the stratosphere.

The tandem solar cell provides the pledge of extra efficient solar modules by combining leading and lower cells that create power at various wavelengths (Figure 3). Tandem cells that accomplish a general effectiveness near 30 percent have been reported, far more than any kind of standard crystalline silicon cell, however they are fabricated with III-V materials, such as gallium arsenide, and their really high production prices ─ several hundred to a number of thousand times greater than for crystalline silicon solar cells ─ severely limit application.

Toshiba has focused its R&D on transparent Cu2O cells. They are formed from naturally plentiful products, which lowers expenses, and use light passage that breaks the ice to outstanding power generation efficiency. Toshiba created the initial transparent Cu2O solar cell in 2019, and demonstrated a Cu2O-Si tandem cell supplying 23.8 percent PCE in the very same year, a time when the typical PCE of stand-alone silicon solar cells was 22 percent.

The firm's newest advance in PCE is the outcome of exact control of CuO and Cu impurities throughout the construction of the cell's Cu2O layer. These contaminations are produced in the present responsive sputtering deposition approach as a result of the nature of the Cu2O, and they are the significant source of diminished PCE and transparency.

Commenting on the innovation, Kazushige Yamamoto, Fellow at Toshiba's Corporate Research & Development Center, said: "X-ray diffraction analysis allows us to identify and measure the degree of the CuO and Cu, providing us information that helps us to identify the very best deposition approach to control the impurities to the lowest level. Our targets are 10 percent PCE for the top Cu2O cell, and 80 percent of transmittance. This development brings us an action more detailed to those goals".

With assistance from NEDO, Toshiba will proceed research to attain the 10% PCE target for leading Cu2O cells. Toshiba is likewise cooperating with Toshiba Energy Systems & Solutions Corporation in the development of massive Cu2O solar cells that are the same size as mass-produced silicon solar cells. The two firms aim to supply samples for outside analyses by FY2023, with a roadmap to finishing manufacturing technologies for industrial products by FY2025.