Figure 7.

Selected upconversion examples taken from the literature. a) Visible and upconverted image of a metal mask positioned behind turbid water, showing that turbid water is transparent to NIR light. Reproduced with permission from Ref. [26], Copyright 2015 Wiley; b) Photo, and c) emitted green light of a see-through all-organic upconversion device, including a transparent top and bottom electrode. Reproduced with permission from Ref. [25], Copyright 2018 ACS; d) Upconverter image of a human forearm with observable subcutaneous blood vessels. Reproduced with permission from Ref. [28], Copyright 2016 Nature; e) Example image made with a colloidal PbSe nanocrystal photodetector combined with a green-emitting OLED, light at 1300 nm was upconverted. Reproduced with permission from Ref. [44], Copyright 2011 ACS.