Discovery of amantadine formate: Toward achieving ultrahigh pyroelectric performances in organics

Pyroelectrics are a class of polar compounds that output electrical signals upon changes in temperature. With the rapid development of flexible electronics, organic pyroelectrics are highly desired. However, most organics suffer from low pyroelectric coefficients or low working temperatures. To date, the realization of superior pyroelectric performance in all-organics has remained a challenge. Here, we report the discovery of amantadine formate, an all-organic pyroelectric with ultrahigh voltage figures of merit (F(v)), surpassing those of all other known organics and commercial triglycine sulfate, LiTaO(3) as well around room temperature. The key to the high F(v) is attributed to large pyroelectric coefficients in a favorable temperature range resulting from a ferroelectric-paraelectric phase transition of second order at 327 K, small dielectric constant, and moderate heat capacity. In addition, amantadine formate is relatively lightweight, soft, transparent, low-cost, and non-toxic, adding value to its potential applications in flexible electronics. Our results demonstrate that a new type of pyroelectrics can exist in organic compounds.