Nanomaterial-Based Capacitive Sensor for Dust Type Differentiation on Surfaces

Current surface dust sensors offer advanced measurement capabilities, especially in determining dust concentration and accumulation ratio using light-scattering mechanisms. However, these sensors are limited in their ability to identify the type or geographical origin of dust particles. Leveraging advances in nanomaterials, we report the fabrication of nanomaterial-based dust sensors capable of differentiating dust samples from different sources under controlled dust loading on the sensor surface. Furthermore, a readout circuit is designed and implemented on a PCB to form an end-to-end sensing platform. Dust samples collected from sand dunes, house roofs, construction sites, and desertified soil are characterized using SEM, XRF, FTIR, and XRD. The results revealed that the dust samples have different morphological structures and elemental distributions, which contribute to their dielectric constants. The sensor capacitance ranged from 1.75 pF to 4.08 pF, and the sensor sensitivity ranged from 8.12% to 118.57%, respectively, as a function of dust type and accumulation level, which varied from 20 mg to 100 mg. In addition, the readout circuit reported a voltage sensitivity of 26-99% at a low dust loading of 20 mg, depending on the dust type. The proposed surface dust sensor has the potential to be integrated into solar panel systems to optimize their performance by enabling automated cleaning initiation when critical dust accumulation thresholds are reached.