All-transparent tandem photovoltaic-powered photodetector

Can electronics operate independently and invisibly in designated places? If yes, the user would not recognize the existence of devices and this can be applied to various applications. The device should be optically transparent and simultaneously achieve transparent electric power to satisfy this invisible freedom. Herein, we propose a dual transparent platform consisting of a broad-range translucent photodetector powered by an invisible photovoltaic unit. Transparent photovoltaic (TPV) has a NiO/TiO2 heterojunction for high optical transparency of 79.7% and can produce a maximum voltage of 0.6 V at an efficiency of 13.4%. A transparent broadband photodetector (TBD) that comprises Co3O4/ZnO has high optical transparency (70%) and provides a broad wavelength photodetection. The TBD can be tuned in the reverse bias mode along with the separate power unit (TPV), which significantly enhances the responsivity to 6.8 mA W−1. In contrast to the self-powered operation mode, the dual system (TBD and TPV power units) can actively control the bias voltage to the TBD, supplied from the TPV (0 to 0.6 V). TPV and TBD have an overall transparency of 56.4% and long-term stability to allow a high degree of freedom in transparent human electronics, ensuring visional transparency and an independent power supply.