(Invited) Development of Ag- and Sn-Based Colloidal Quantum Dots for Near Infrared Photodetection

• DOI: 10.1149/ma2024-01231391mtgabs
• Publication Date: 2024-08-19T15:21:30Z
• Authors: Jianying Ouyang; Neil Graddage; Jianping Lu; Barbara Martin; Tyler Davidson-Hall; Ye Tao; Jianfu Ding; Patrick Malenfant
• Keywords: Photodetection

Low-cost photodetectors with sensitivity in the second near-infrared window (NIR-II, 1000–1700 nm) are highly demanded. Recently, we made first demonstration of an Ag 2 Se colloidal quantum dots (QDs) photodiode up to 1200 nm. By employing secondary phosphine elevate precursor reactivity, QDs a distinct excitonic absorption peak was achieved. These nanocrystals were deposited from solution into mesoporous TiO scaffold increase light and charge separation reduce exciton diffusion length. incorporating suitable hole-transporting layer between active anode, resulting devices showed responsivity 4.17 mA/W at 1 Also, Te excellent for advancing detection wavelength. Their synthesis desired particle sizes, narrow size distribution high photoluminescence yield (PL QY) is challenging. We systematically investigate critical parameters affecting organic phase. It shows that Ag/Te feed ratio leads smaller higher PL QY; under 4:1 molar ratio, addition narrower stability; 6:1 excess 1-dodecanethiol as strong ligand slows nucleation results fewer nuclei, leading broad poor optical properties; additional n-trioctyl weak provides better another n-tributylphosphine improves QD stability, focuses distribution, enhances QY. After optimization relatively large peaks (~1050 – 1450 emission 1.3 1.7 µm (QY 6.2%) obtained. NIR-II photodetection has been demonstrated ~1.5 1400 More recently, have developing Sn-based chalcogenide obtained preliminary results. demonstrate Sn offer low-toxicity route low-cost fabrication photodetection. Reference: [1] Graddage N, Ouyang J, Lu Chu TY, Zhang Y, Li Z, Wu X, Malenfant PRL, Tao Y. Near-Infrared-II Photodetectors Based on Silver Selenide Quantum Dots Mesoporous Scaffolds. ACS Applied Nano Materials 2020 , 3: 12209–12217. [2] Zhong Kodra O, Ding J. Colloidal Photodetectors. 2021 4: 13587–13601. Keywords: Environmentally Friendly; Near Infrared; Dots; Photodetection.