A hybrid pyro-phototronic nanogenerator (HPyNG) for ultra-low light detection

Abstract

We report the fabrication of a hybrid pyro-phototronic nanogenerator (HPyNG) based on a heterojunction formed between two materials having different pyroelectric origins, viz. inorganic zinc oxide (ZnO) and an organic polyaniline–crystalline rubrene thin film. ZnO exhibits pyroelectric behaviour due to its non-centrosymmetric crystal structure, while the crystalline rubrene-containing organic matrix, a centrosymmetric material, demonstrates pyroelectric properties due to the surface layer polarization effect. The interface between these materials forms an efficient junction, which enhances photovoltage generation through synergistic pyroelectric and optoelectronic effects. However, the pyroelectric polarization effects generated in the ZnO film and the crystalline rubrene are found to oppose each other, introducing another unique dimension to this device's functionality. The figures of merit of the nanogenerator are highly competitive with existing technologies, and its ultra-low light detection sensitivity, down to 50 nW, further underscores its unique capabilities. This study transcends the mundane synthetic processes and involves a novel approach to nano-electronic device fabrication using multiple pyroelectric materials with promising applications in low-intensity light sensing.