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arXiv · 2308.12250

Fast near-infrared photodetectors based on nontoxic and solution-processable AgBiS2

Yi-Teng Huang·Davide Nodari·Francesco Furlan·Youcheng Zhang·Marin Rusu·Linjie Dai·Zahra Andaji-Garmaroudi·Samuel D. Stranks·Henning Sirringhaus·Akshay Rao·Nicola Gasparini·Robert L. Z. Hoye
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Abstract

Solution-processable near-infrared (NIR) photodetectors are urgently needed for a wide range of next-generation electronics, including sensors, optical communications and bioimaging. However, there is currently a compromise between low toxicity and slow (<300 kHz cut-off frequency) organic materials versus faster detectors (>300 kHz cut-off frequency) based on compounds containing toxic lead or cadmium. Herein, we circumvent this trade-off by developing solution-processed AgBiS2 photodetectors with high cut-off frequencies under both white light (>1 MHz) and NIR (approaching 500 kHz) illumination. These high cut-off frequencies are due to the short transit distances of charge-carriers in the AgBiS2 photodetectors, which arise from the strong light absorption of these materials, such that film thicknesses well below 120 nm are adequate to absorb >65% of near-infrared to visible light. By finely controlling the thickness of the photoactive layer, we can modulate the charge-collection efficiency, achieve low dark current densities, and minimize the effects of ion migration to realize fast photodetectors that are stable in air. These outstanding characteristics enable real-time heartbeat sensors based on NIR AgBiS2 photodetectors. # equal contribution, * corresponding authors

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Yi-Teng Huang, Davide Nodari, Francesco Furlan, Youcheng Zhang, Marin Rusu, Linjie Dai, Zahra Andaji-Garmaroudi, Samuel D. Stranks, Henning Sirringhaus, Akshay Rao, Nicola Gasparini, Robert L. Z. Hoye. 2023-08-23. Fast near-infrared photodetectors based on nontoxic and solution-processable AgBiS2. https://doi.org/10.1002/smll.202310199

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