Charge Transport Behavior and Ultrasensitive Photoresponse Performance of Exfoliated F₁₆CuPc Nanoflakes

Abstract Air‐stable, photosensitive copper hexadecafluorophthalocyanine (F₁₆CuPc) is a promising n‐type semiconductor for organic electronics and optoelectronics. However, the performance of F₁₆CuPc‐based devices is significantly limited by the poor crystallinity of thin films. Here, the charge transport and electrical contact behavior of F₁₆CuPc nanoflakes, mechanically exfoliated from needle‐like bulk single crystals, are probed by analyzing the temperature‐dependent carrier mobility and conductance, where the multiple‐trap/release‐ and band‐like transport mechanism govern the charge transport at different temperature ranges and carrier densities. F₁₆CuPc nanoflake‐based field effect transistors (FETs) exhibit high on‐state current and ON/OFF ratio, one‐order magnitude higher than those of reported F₁₆CuPc nanowires, thin films, and nanoribbons. Besides, F₁₆CuPc nanoflake‐based phototransistors exhibit attractive photoresponse performance in the spectral range of 300–750 nm even at quite low operating source–drain voltage (1 V), with maximum photoresponsivity of 19 A W⁻¹, detectivity of 8 × 10¹² Jones, and fast response speed of 36 ms, which is attributed to the single‐crystalline characteristic of nanoflakes, and the resultant efficiently exciton diffusion and charge transport. The work demonstrates that 2D organic nanoflakes with single‐crystalline feature will be promising candidates for flexible electronic and optoelectronic devices.