Fully solution-processed semi-transparent, flexible, self-powered broadband photodetector based on two-dimensional PbI2 nanoplates

초록

The use of multiple detectors to recognize various wavelengths often complicates integration systems and reduces overall detection efficiency. Numerous key challenges exist in fabricating a single photodetector capable of broad-spectrum response under unbiased conditions while maintaining transparency, flexibility, and compatibility with high-density integration. These characteristics are particularly important for next-generation applications in the Internet of Things as well as in transparent and wearable optoelectronic devices. In this study, a broadband ultraviolet-to-visible photodetector based on PbI2 nanosheets was fabricated through a fully solution-processed approach using PEDOT:PSS as the transparent top electrode. This structure provides excellent optoelectronic performance and mechanical flexibility without compromising transparency. The intrinsic built-in potential enables self-powered operation. The fabricated photodetector exhibited a responsivity of 10.8 mA/ W, a specific detectivity of 1.86 x 1011 Jones, and external quantum efficiency of 2.54 % under 455 nm illumination in unbiased conditions. It also demonstrated excellent cycling stability under repeated light on/off switching, a rapid response speed of 200/110 ms, and wide spectral sensitivity in the 365-530 nm range. Furthermore, the flexible devices maintained stable performance under different bending angles (30 degrees, 60 degrees, 90 degrees, and 120 degrees) and continuous bending cycles (1200), confirming their potential for large-area flexible and wearable optoelectronic applications.

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