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

Abstract 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 × 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 ≈10 4 , and a high specific detectivity ( D *) of ≈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.