Spin-On-Patterning of Sn-Pb Perovskite Photodiodes on IGZO Transistor Arrays for Fast Active-Matrix Near-Infrared Imaging

Flat-panel imagers have wide applications in industrial and medical inspections. Nonetheless, large area infrared imaging remains a challenge due to the fact that the state-of-the-art infrared sensors are usually based on silicon or germanium technologies, which are limited by the wafer size. Recent advances in low bandgap Sn-Pb perovskite photodiodes (PDs) and indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) matrix backplane bring new opportunity for developing the large area near-infrared image sensor. As a proof of concept, a 12 x 12 pixels array with each pixel independently controlled by the gate voltage of a TFT are constructed. Arrays of Sn-Pb based perovskite PDs are spin deposited onto the IGZO TFT drain electrode via self-assembled patterning process. The low bandgap perovskite PD exhibits a broad spectral response for wavelength from 300 to 1000 nm, featuring a high light to the dark current ratio of approximate to 10(4), and a high specific detectivity (D*) of approximate to 10(11) Jones at 850 nm (biased at -0.1 V). The integration takes advantage of the high mobility of IGZO transistors and the high infrared sensitivity of low Sn-Pb perovskite materials, which enables the next generation near-infrared flat-panel imager with high frame rate and low operating voltages.