上转换发光量子点

Upconversion Luminescence in Quantum Dots

光子上转换是一种重要的非线性反斯托克斯发光现象,在激光、显示、光伏、信息安全以及生物成像与诊疗等领域具有应用前景。与研究较多的有机分子三重态-三重态湮灭和稀土掺杂纳米颗粒上转换发光材料相比,上转换量子点可以在宽光谱激发范围内实现上转换发光,具有频谱吸收宽、发光效率高、近红外可吸收、能带可调、尺寸小以及稳定性高等特点,引起了领域内的关注。本文介绍了上转换发光的种类及机理,对近年来上转换发光量子点的研究进展进行了总结,重点分析了基于激发态吸收的半导体双量子点的类型和设计原理,探讨了上转换发光量子点在发光二极管(LED)、光电探测、生物标记、太阳能电池等方面的应用潜力,特别是未来发展面临的挑战和前景。

Photon upconversion(UC),a nonlinear optical process that converts multiple low-energy photons into a single high-energy photon,is of significant importance in many fields,such as laser,display,photovoltaic,information security,bioimaging and diagnosis.In compare with the well developed lanthanide-doped nanocrystals and triple-triple annihilation,UC quantum dots can achieve UC luminescence under a wide spectral excitation range,which are emerging as promising candidates for many photonic applications due to their wide spectral absorption,high luminous efficiency,near-infrared absorption,tunable energy band,small size and high stability.In this short review,we summarize the progress of upconversion semiconductor quantum dots with the description of basic mechanisms,recent progress of different types of UC quantum dots,especially UC dual quantum dots that based on excited state absorption,discuss the application potential of UC quantum dots in light-emitting diodes,detectors,solar cells and biomarkers,then we conclude with a brief prespective about the challenges and future prospects in this field.