Photodetection in the Infrared with heavy metal-free QUANTum dots – PIQUANT

Due to their unique and size-tuneable properties, quantum dots (QDs) have become established building blocks for diverse applications, in particular in display and biotechnologies. For the visible range alternative materials to highly toxic Cd-based QDs exist (e.g., InP, AgInS2), but the near infrared (NIR) and shortwave infrared (SWIR) range is still dominated by lead- and mercury-based QDs (e.g., PbS, HgTe). This range is of particular interest for numerous applications such as night vision, smartphones, wireless optical communication, photon up-conversion etc.

We identified indium antimonide (InSb) and silver chalcogenides (Ag2Se, Ag2Te) as highly promising materials for NIR QDs, combining wide spectral tunability and absence of toxic elements such as Cd, Hg and Pb. However, the synthetic chemistry of these materials is much more challenging than for more established QDs. We propose novel synthetic approaches aiming at high-quality InSb and Ag2X QDs as well as their core/shell structures (WP1). The electronic properties (energy level positions) of the obtained QDs will be assessed using photoelectron spectroscopy and they will be integrated into photoconductive devices to probe the spectral and temporal response and signal-to-noise ratio under near infrared illumination (WP2). To fully assess their potential as emerging NIR QDs, we will also investigate their stability, degradation mechanisms and toxicity profile in vitro (cell culture) and in vivo (plant models) (WP3).

The objectives of PIQUANT are threefold: first, we target the synthesis of monodisperse core and core/shell NIR QDs in a wide size range. Second, we will evaluate their performance as active layer in NIR/SWIR photodetectors. Finally, we will assess the (eco-)toxicity using in vivo (plants) and in vitro models of the main target organs in humans.