Photoresponsive characteristics of thin film transistors with perovskite quantum dots embedded amorphous InGaZnO channels

Photodetectors based on amorphous InGaZnO (a-IGZO) thin film transistor (TFT) and halide perovskites have attracted attention in recent years. However, such a stack assembly of a halide perovskite layer/an a-IGZO channel, even with an organic semiconductor film inserted between them, easily has a very limited photoresponsivity. In this article, we investigate photoresponsive characteristics of TFTs by using CsPbX₃ (X=Br or I) quantum dots (QDs) embedded into the a-IGZO channel, and attain a high photoresponsivity over 10³A·W^-1, an excellent detectivity in the order of 10¹⁶ Jones, and a light-to-dark current ratio up to 10⁵ under visible lights. This should be mainly attributed to the improved transfer efficiency of photoelectrons from the QDs to the a-IGZO channel. Moreover, spectrally selective photodetection is demonstrated by introducing halide perovskite QDs with different bandgaps. Thus, this work provides a novel strategy of device structure optimization for significantly improving the photoresponsive characteristics of TFT photodetectors.