High-Performance and Stable Colloidal Quantum Dots Imager via Energy Band Engineering

Abstract

Solution-processed colloidal quantum dot (CQD) photodiodes are compatible for monolithic integration with silicon-based readout circuitry, enabling ultrahigh resolution and ultralow cost infrared imagers. However, top-illuminated CQD photodiodes for longer infrared imaging suffer from mismatched energy band alignment between narrow-bandgap CQDs and the electron transport layer. In this work, we designed a new top-illuminated structure by replacing the sputtered ZnO layer with a SnO 2 layer by atomic layer deposition. Benefiting from matched energy band alignment and improved heterogeneous interface, our top-illuminated CQD photodiodes achieve a broad-band response up to 1650 nm. At 220 K, these SnO 2 -based devices exhibit an ultralow dark current density of 3.5 nA cm −2 at −10 mV, reaching the noise limit for passive night vision. The detectivity is 4.1 × 10 12 Jones at 1530 nm. These SnO 2 -based devices also demonstrate exceptional operation stability. By integrating with silicon-based readout circuitry, our CQD imager realizes water/oil discrimination and see-through smoke imaging.

All-inorganic Sb2S3-based two-terminal tandem solar cells enable over 10.9% efficiency employing a concise interconnection layer

“…S2†), it became apparent that the energy band alignments among diverse functional layers within the device were well matched. The PbS-EDT layer operated as a strong p-type layer, while ZnO served as a typical n-type layer, 27,34 ensuring that our new developed ICL effectively extracts photogenerated charge carriers from the subcells. Nevertheless, in contrast to ZnO, ALD SnO 2 showed a lower φ .…”