High‐Leakage‐Resistance and Low‐Turn‐On‐Voltage Upconversion Devices Based on Perovskite Quantum Dots.

In recent years, the remarkable optoelectronic characteristics exhibited by perovskite quantum dots (PQDs) have captured significant attention, which has spurred numerous investigations and novel applications. Nonetheless, the development of solution‐processed upconversion devices (UCDs) has predominantly centered around the utilization of organic materials, 3D perovskite films, and II‐VI quantum dots. In this work, PQDs are utilized for the first time as emission materials to enhance UCD performance. The stability of PQDs, synergistic coverage effect between PQDs and hole‐transporting layers (HTLs), and the interfaces of CGL/HTL are investigated in an attempt to identify the primary factor affecting UCD performance. The optimized UCD incorporating with effective TAPC HTLs demonstrate a maximum luminance of 463.9 cd m−2 at 520 nm (biased at 12 V and irradiated under 785 nm NIR light) accompanied by significant current gains of 167 times (at 3.4 V) and a noteworthy photon‐to‐photon conversion efficiency of 5.68% (at 12 V). The impressive performance is accompanied by a remarkably low turn‐on voltage of 1.4 V and a high leakage voltage of up to 12 V, making the highest record reported for solution‐processed UCDs. [ABSTRACT FROM AUTHOR]