Fig. 4: Retainable photocurrent at ambience, large-scale sample preparation, and photodetector device.

a Comparison of ambient on-off photocurrent responses before compression (gray), after first (light red) and second (dark red) compression-decompresion cycles, showing notable generation and increase in the photocurrent after pressure treatments. b, Mean squared distances of the Rb, I, S, and Re atoms. The fluctuations stabilized with increasing time in the molecular dynamics simulations. c Scheme of the LVP utilized in applying pressure treatment to a large-scale Rb₆Re₆S₈I₈ sample. Scale bar, 1 mm. d Sketch of a Schottky-type thin-film Rb₆Re₆S₈I₈ photodetector device. e Good solution processability of the decompressed Rb₆Re₆S₈I₈ sample. The optical picture of LVP-treated Rb₆Re₆S₈I₈ dissolved in DMF confirmed that the material is dispersible, where the rubidium iodide ([Rb₆I₂]⁴⁺) framework is stable, rather than behaving as Rb⁺ and I^- in DMF. f Photograph of the LVP-treated Rb₆Re₆S₈I₈-based photodetector device and the on-device interdigitated Pt electrode imaged under a microscope. g The I-V curve of devices under 367-nm illumination. h On-off photocurrents under 367-nm illumination. i The I-V curve of devices under 520-nm illumination. j On-off photocurrents under 520-nm illumination. For all tests, no bias voltage is involved, and the devices are self-powered. k Response time and specific detectivity (D^*) with both 367 nm and 520 nm illuminations. Here, τ_r and τ_d denote the rise and decay response times, respectively. l Schematic diagram of the device ultraviolet and visible imaging device. The photocurrent mappings are observed with the specific pattern obtained by irradiating the device with the “HPSTAR” logo mask using the 367 nm ultraviolet and 520 nm visible lasers. “Max” and “Min” in the color scale denote the relative magnitudes of photocurrent activity. As such, the adoption of LVP in combination with permanent photocurrent generation from high-pressure treatment thus allows practical and scalable device applications.