Flexible and transparent MXene-platformed ultrafast photodetector for encrypted signal communication in self-powered operation

The record-high responsivity of 0.34 A W−1 is achieved by flexible and transparent Ti3C2Tx-platformed photodetectors (PDs) in self-powered operation. Transparent technology is suitable for future human electronic interface. The Ti3C2Tx/3D semiconductor (Tx = –F, –OH, –O, –Cl) structure has gained considerable attention in the design of high-performance optoelectronic devices. In particular, the unique mechanical and hydrophilic properties of Ti3C2Tx are favored for large-scale flexible photodetectors. However, the self-powered operation and transparency have remained unexplored for Ti3C2Tx/3D semiconductor-based flexible PDs. To access portable and implantable electronic devices, Ti3C2Tx was comprehensively utilized as an active electrical window and charge-transporting layer for transparent PDs. Density functional theory revealed the better charge-transporting channel due to the Ti3C2Tx-functional layer, resulting in the elevated pyro-phototronic current of Ti3C2Tx/Al2O3/ZnO/Ti3C2Tx/ITO/polyethylene terephthalate (PET) PDs. Based on the ultrafast photo-response of the PD (8 μs), an optically transparent (> 68 %) communication system was developed. The flexible and transparent PD (TPD) can process the incident Morse codes of encrypted optical signals to text ("MXENE TPD") information effectively. This study combines the transparency and self-reliant characteristics into a wearable MXene/bulk semiconductor-based PD, exhibiting great potential for applications in energy-efficient imaging, communication, and health monitoring systems.