Green Chiral-Polar Halide Double Perovskite for Sensitive Self-Driven X-ray Detection

Abstract

The lead-free metal halide perovskites (MHPs) have emerged as prospective, environmentally friendly, and high-performance candidates for X-ray detection owing to their prominent X-ray absorption capacity and low toxicity. Nevertheless, the energy consumption caused by high external operational voltages and severe ion migration limit the stability of lead-free MHPs for X-ray detection. Here, through the incorporation of alternating chiral–achiral spacer cations, we synthesized a novel lead-free chiral-polar perovskite, (R-MPA)₂(PA)₂AgBiBr₈ (1R, R-MPA = R-methylphenethylammonium, PA = propylamine). The intrinsic spontaneous electric polarization yields an obvious bulk photovoltage (0.25 V), facilitating the separation and transport of photogenerated carriers, which makes self-driven detection possible. Consequently, the 1R-based X-ray detector achieves a high sensitivity (131 μC·Gy^–1·cm^–2) and a detection limit as low as 62.6 nGy·s^–1 at 0 V bias. This study indicates the huge potential of chiral-polar lead-free MHPs in realizing superior self-driven X-ray detection, and provides an approach to the design of highly promising self-driven X-ray detection materials.

Keywords

Bulk photovoltaic effect / Lead-free / Chiral-polar hybrid perovskite / Self-driven X-ray detection / 2D perovskites / Chirality

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2026 SIOC, CAS, Shanghai, & WILEY-VCH GmbH