Solution-Processed Infrared Optoelectronics: Photovoltaics, Sensors, and Sources

The fabrication of optoelectronic devices via spin-coating onto an arbitrary substrate offers ease of integration, low cost, and physical flexibility. Reports of active optoelectronic devices operating in the IR, and made via solution-processing, emerged in the early 2000s. Here, we review progress in IR solar cells, image sensors, and optical sources based on solution-processed materials. The latest solution-processed photovoltaics (PV) now provide 4.2% power conversion efficiencies in the IR, placing them a factor of 3 away from enabling a doubling in overall solar power conversion efficiency of today's best visible-wavelength solution-processed PV. The best solution-processed photodetectors now provide sensitivities in the 10
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range, exceeding the sensitivity of the best epitaxially grown short-wavelength infrared photodetectors. Infrared optical sources, both broadband light-emitting diodes and, more recently, lasers, have now also been reported at 1.5 mum. We review the progress and future prospects of this rapidly advancing field.