Research Projects

Halide Perovskites (HPs), with their tunable bandgap, strong light absorption, mixed ionic-electronic conductivity, long carrier diffusion lengths, and low-cost fabrication, are promising for next-generation flexible and portable optoelectronics. The mixed ionic-electronic conductivity of HPs makes the perovskite/electrolyte interface a crucial region for a wide range of applications. Due to the migration and polarization of ions and defects, tunable by external electric fields and light illumination, HPs are promising for three terminal electrolyte-gated transistors (EGTs), neuromorphic devices (NDs), self-powered photodetectors (SPPDs), switching memories, and logic gate devices (LGDs). Transistors serve as the fundamental building blocks of numerous electronic devices; however, high energy consumption and heat dissipation pose significant challenges, which can be resolved by reducing the contact resistance and employing dielectrics with high dielectric constants. Using an electrolyte as the gate insulator, offering high capacitance can help to overcome this problem to reduce operating voltage. The formation of an electric double layer (EDLC) at the interface can yield extremely high capacitance, reducing power consumption. The electrolyte/semiconductor interface holds great promise, as the ions in the electrolyte can be modulated by the polarity and strength of the applied voltage. The migration of ionic species and vacancies within the perovskite lattice can be effectively modulated by external electric fields and optical illumination. The concentration and dynamics of these mobile defects play a critical role in the resistive switching behavior and memory effects in perovskite-based memristive devices and are fundamental to enabling neuromorphic computing. Two-terminal neuromorphic devices (2TNDs) based on metal-semiconductor-metal architectures have been extensively investigated, where the resistive switching mechanism is primarily depends on the formation and rupture of conductive filaments, formed by the migration of ions and vacancies. Three-terminal neuromorphic devices (3TNDs) offer superior performance over 2TNDs by enabling independent control of channel conductance via the gate bias, thereby separating read and write operations. This reduces signal interference and allows more precise and stable modulation of synaptic weights. In this proposal, we introduce for the first time, a stable light controlled dual-gated, HPs-based NDs, incorporating a transparent dielectric layer (TDL) as bottom gate deposited below the perovskite layer to control the channel current by mitigating the ions movement and top electrolyte gate for additional control on channel current. A TDL enables photon-controlled channel conductivity, enhancing efficiency and processing speed beyond conventional electron-only devices. For the first time, we also propose a novel self-powered EGTs (SP-EGT) structure using monolithic integration of SPPD with the EGT.