Iron Pyrite (FeS₂) Broad Spectral and Magnetically Responsive Photodetectors

Earth‐abundant iron pyrite (FeS₂) nanocrystals show great potential in broad photosensing applications due to their high photoabsorption coefficient (>10⁵ cm⁻¹) and ideal bandgap (0.95 eV). However, broad spectral photodetectors using the FeS₂ nanojunctions and external stimuli‐driven photoresponse have not been demonstrated yet. Here, broad spectral FeS₂/CdS bulk nanojunction photodetectors are demonstrated, covering the UV‐Vis‐NIR wavelength range. This is the first time shape‐dependent FeS₂ nanocrystals and a dilute magnetic semiconductor phase exhibiting fast photoresponse time (10 ms) and high responsitivity (174.9 A/W) is demonstrated. Tunable photocurrent (73% change) is observed under the magnetic field effect due to the interdiffusion‐controlled diluted magnetic semiconductor CdFeS phase. The broad spectral FeS₂‐based photodetectors open up a new tactic for solution‐processed next generation efficient and sustainable photosensing devices.