Open-circuit Voltage Exceeding 840 mV for All-Sputtered CdS/CdTe Devices

Sputtering is an efficient way to fabricate CdTe solar cells. However, the open-circuit voltage (Voc) of a sputtered device is low compared to close space sublimation or vapor deposited CdTe devices. Here, we report an outstanding Voc > 840 mV and fill factor (FF) > 71.0% for all-sputtered CdS/CdTe solar cells. These results were achieved by solution-based copper (Cu) doping of CdTe by copper (II) chloride (CuCl
₂
) in deionized water. Compared with evaporated Cu, solution-based doping increased the Voc and FF, and improved the optoelectronic properties of the sputtered CdTe thin films. Capacitance-voltage measurements indicated that the free hole concentration increased by two-fold for CuCl
₂
treated devices.