Optical Learning and Reconfigurable Logic Utilizing Halide Perovskite Thin Film Transistors

Metal halide perovskites with their superior electronic properties, solution processibility, and scalability, are promising candidates for optoelectronic applications such as solar cells and LEDs. Although of importance for ubiquitous, intelligent electronics, reports on the application of thin film transistors (TFTs) fabricated from perovskites are sparse, primarily due to operational conditions limitations and stability issues. Precise control of composition, microstructure as well as novel chemical treatments have been proposed as solutions to this quandary. Here, a room temperature operational n-type solution-processed Cs_0.05(MA_0.15FA_0.7)Pb(Br_0.5I_2.4) triple cation transistor enabled using tin-doped indium oxide as source/drain contacts is reported. Optical learning is demonstrated by exploiting the inherent photo response of the perovskite channel and gate bias modulation capability of such perovskite TFT optical pixels. The pixels show modulatable learning and forgetting behavior as demonstrated by the training of alphabets. Noise-free optoelectronic relearning is also demonstrated. Finally, the intelligent transistor is also utilized to demonstrate reconfigurable logic, switchable between 'OR' and 'AND' states, demonstrating the versatility of the halide perovskite pixel.