A high-performance self-powered photodetector based on solution-processed nitrogen-doped graphene quantum dots/all-inorganic perovskite heterostructures

In this work, a self-powered and high-performance vertical type photodetector based on solution-processed nitrogen-doped graphene quantum dots and all-inorganic perovskite nanocrystals heterostructure is achieved. The vertical type NGQDs/CsPbBr3 heterojunction photodetector was fabricated using two steps of standard lithography process and drop-casting method. The vertical type NGQDs/CsPbBr3 photodetector (VTPD) exhibited a nonlinear I-V curve with an extremely low dark current of 0.38 nA and 0.29 nA at forward and reverse bias voltage of 3 V, and - 3 V, respectively. Moreover, the vertical type NGQDs/CsPbBr3 photodetector exhibited superior figure of merits (high-performance) with a light current (257.71 nA), an on/off ratio (670), responsivity (R = 3.21 A/W), specific detectivity (D* = 2.9 x 10(12) J), and an external quantum efficiency (EQE = 270%) under illumination of light source with a wavelength of 520 nm and power intensity of 0.8 mW/cm(2) at bias voltage of 3 V. In addition, the vertical type NGQDs/CsPbBr3 photodetector is confirmed to operate without an external bias voltage demonstrating the obvious photovoltaic characteristics of the device at 0 V. The performance of vertical type NGQDs/CsPbBr3 photodetector (VTPD) is not only surpass the performance of planar type NGQDs/CsPbBr3 photodetector (PTPD) fabricated in this work but also the performance of recently reported self-powered PDs based on carbon/perovskite, and perovskite/perovskite heterostructure. These results pave the way for exploiting solution-processed NGQDs/CsPbBr3 heterojunction to fabricate low-cost, self-powered, and high-performance optoelectronics such as solar cells, light emitting diodes, lasers, and photodetectors.

Automated summary

A self-powered and high-performance vertical photodetector based on solution-processed nitrogen-doped graphene quantum dots and all-inorganic perovskite nanocrystals has been successfully achieved. The vertical photodetector exhibited an extremely low dark current and superior figure of merits under illumination, and it operated without an external bias voltage. Its performance surpassed that of planar photodetectors and recently reported self-powered photodetectors based on carbon/perovskite and perovskite/perovskite heterostructures. These results pave the way for the fabrication of low-cost, self-powered, and high-performance optoelectronic devices using solution-processed heterojunctions.