Highly Efficient Top‐Emitting Infrared‐to‐Visible Up‐Conversion Device Enabled by Microcavity Effect

Abstract

Infrared (IR)-to-visible up-conversion device allows a low-cost, pixel-free IR imaging over the conventional expensive compound semiconductor-based IR image sensors. However, the external quantum efficiency has been low due to the integration of an IR photodetector and a light-emitting diode (LED). Herein, by inducing a strong micro-cavity effect, a highly efficient top-emitting IR-to-visible up-conversion device is demonstrated where PbS quantum dots IR-absorbing layer is integrated with a phosphorescent organic LED. By optimizing the optical cavity length between indium tin oxide (ITO)/thin Ag/ITO anode and semi-transparent Mg:Ag top cathode, the up-conversion device yields 15.7% of photon-to-photon conversion efficiency from the topemission. The high efficiency can be achieved under a low IR transmission through the semi-reflective anode. Finally, pixel-free IR imaging is demonstrated using the up-conversion device, boosting the effect of micro-cavity on the brightness and the contrast of an IR image.

A high-performance dual-functional organic upconversion device with detectivity approaching 1013 Jones and photon-to-photon efficiency over 20%

“…Consequently, the combination of the two high-performance subunits not only breaks free from the dependence on heavymetal emitters, but also enables the UCD to realize outstanding performance, that is, a D* approaching 10 13 Jones and Z p-p of over 20% were achieved for the electron and photon readout, respectively. This performance is one of the best among reported UCDs with various material systems [11][12][13][14][15][16][17][18]20 (listed in Table 1). Thanks to the high D* and Z p-p , the detectable light power is as little as 0.29 mW cm À2 and the display contrast is over 70 000 : 1 under 850 nm light, making the UCD a good platform for NIR detection and imaging in real applications.…”

“…1b). 11–20 Amongst them, organic NIR-UCDs, owing to the superior characteristics of organic materials, have attracted notable attention because of their unique advantages of low cost, large area, solution-processable preparation and flexibility. 10–15,17…”

“…1b). [11][12][13][14][15][16][17][18][19][20] Amongst them, organic NIR-UCDs, owing to the superior characteristics of organic materials, have attracted a School of Optoelectronic Science and Engineering, University of Electronic Science notable attention because of their unique advantages of low cost, large area, solution-processable preparation and flexibility. [10][11][12][13][14][15]17 A typical organic UCD is mainly constructed by connecting an NIR organic detecting subunit with an organic emitting subunit.…”

P‐Type PbS Quantum Dot Solar Ink via Hydrogen‐Bonding Modulated Solvation for High‐Efficiency Photovoltaics

“…PbS colloidal quantum dots (CQDs) are promising solutionprocessable optoelectronic materials with the advantages of tunable bandgap, broad spectral response, and multi-exciton generation effects, [1][2][3] which are widely used in various optoelectronics, such as the sensors, [4,5] photodetectors, [6,7] field-effect transistors (FETs) [8,9] and solar cells. [10][11][12] Research efforts on stable and functionalized CQD inks have encouraged the development of various solution-processed deposition technologies of CQD including printing, roll-to-roll, and spray coating.…”

Realizing an Optical Micro‐Cavity in a CuCo2O4‐W‐CuCo2O4 Thin Film Stack for Spectrally Selective Solar Absorbers

“…Also, they can be an alternative to the nitrides [ 19 ] and oxy‐nitride coatings [ 20 ] in the multilayer absorbers because of the ease of fabrication. Recently optical micro‐cavity‐based structures have gained immense attention due to their ability to achieve and tune spectral selective absorption leading to better photovoltaic efficiency, [ 21 ] energy upconversion, [ 22 ] transparent optical devices, [ 23 ] extremely low reflectance, [ 24 ] and also new physics phenomena. [ 25 ] Quasi‐optical micro‐cavities (QOMs) are reported for their increased absorption in the solar spectrum range by modifying the optical constants of each layer.…”