Dual Behavior of Transparent Conducting CuS Ultrathin Film

Charge carrier type interconversion in undoped semiconducting materials is challenging, as it is primarily directed by intrinsic defects with low formation enthalpies and ionization energy. Therefore, interconversion of p- to n-type materials without any external influence is very difficult, and no synthesis protocol is known to convert it. Overcoming this problem enables the formation of p-n homojunction-based solar cells. In this account, p- and n-type transparent, conducting ultrathin films of CuS have been developed by decreasing the thickness. Furthermore, these transparent p- and n-type conducting materials (TCMs) are used as optoelectronic devices, including light-emitting diodes and p-n homojunction solar cell applications.