The semiconductor nature of chemiresistive gas sensors renders their detection accuracy highly vulnerable to operational temperature fluctuations, where even minor thermal fluctuations trigger baseline resistance drift, leading to unreliable readings. Researchers have sought a material-level breakthrough—integrating gas sensitivity and temperature stability into a single platform—to overcome this critical limitation.

In a study published in Nature Communications, a research group led by Prof. XU Gang and Prof. WANG Guan'e from Fujian Institute of Research on the Structure of Matter of the Chinese Academy of Sciences designed and synthesized a novel organic-inorganic hybrid covalent superlattice material, AgBDT (BDT = 1,4-benzenedithiol), and proposed a ratiometric sensing mechanism to combat temperature drift.

The distinctive structure of AgBDT integrates a two-dimensional inorganic [AgS]_n layer with organic benzene rings, forming a multi-quantum well superlattice that synergistically enhances photoelectric and gas-sensing functionalities. This design significantly amplifies the photoelectric response, achieving a record on/off ratio of 1770 among conductive coordination polymers.

Concurrently, the surface-anchored sulfhydryl groups furnish abundant NO₂ adsorption sites through Lewis acid-base interactions and hydrogen-bonding, facilitating strong electron transfer (0.27 e⁻ per NO₂ molecule) as confirmed by density functional theory (DFT) calculations, which explains the high sensitivity with a response value of 15000% towards 100 ppm NO₂.

These calculations elucidate p-type semiconductor characteristics of AgBDT, demonstrating how dynamic modulation of photoinduced hole concentration governs its photoelectric response, thereby establishing an electronic structure-level theoretical framework for its exceptional performance.

Researchers innovatively introduced a ratiometric-gas sensing detection strategy, using the photoelectric response (R_ph) as an internal reference to gas-sensitive signals (R_gas). By calculating the ratio R_gas/R_ph, they effectively eliminated the influence of temperature-induced baseline drift. Experimental results confirmed the exceptional stability of NO₂ detection across a broad temperature range of 25–65°C, slashing temperature-induced variability by 64% (CV: 7.81% vs. 21.81%).

This study pioneers the integration of ratiometric sensing with organic-inorganic hybrid superlattices, which resolves the challenge of temperature drift and opens up new avenues for “self-correcting” sensors.