Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.
Key Laboratory of Flexible Electronics and Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing, 211816, China.
Adv Mater. 2018 Jun;30(23):e1707235. doi: 10.1002/adma.201707235. Epub 2018 Apr 30.
At the heart of electrically driven semiconductors lasers lies their gain medium that typically comprises epitaxially grown double heterostuctures or multiple quantum wells. The simultaneous spatial confinement of charge carriers and photons afforded by the smaller bandgaps and higher refractive index of the active layers as compared to the cladding layers in these structures is essential for the optical-gain enhancement favorable for device operation. Emulating these inorganic gain media, superb properties of highly stable low-threshold (as low as ≈8 µJ cm ) linearly polarized lasing from solution-processed Ruddlesden-Popper (RP) perovskite microplatelets are realized. Detailed investigations using microarea transient spectroscopies together with finite-difference time-domain simulations validate that the mixed lower-dimensional RP perovskites (functioning as cladding layers) within the microplatelets provide both enhanced exciton and photon confinement for the higher-dimensional RP perovskites (functioning as the active gain media). Furthermore, structure-lasing-threshold relationship (i.e., correlating the content of lower-dimensional RP perovskites in a single microplatelet) vital for design and performance optimization is established. Dual-wavelength lasing from these quasi-2D RP perovskite microplatelets can also be achieved. These unique properties distinguish RP perovskite microplatelets as a new family of self-assembled multilayer planar waveguide gain media favorable for developing efficient lasers.
电驱动半导体激光器的核心是其增益介质，通常由外延生长的双异质结构或多量子阱组成。与这些结构中的包层相比，活性层具有更小的带隙和更高的折射率，这为载流子和光子的同时空间限制提供了条件，有利于光增益增强，从而有利于器件的运行。通过模拟这些无机增益介质，实现了具有高度稳定的低阈值（低至≈8µJ cm）线性偏振激光的溶液处理的 Ruddlesden-Popper（RP）钙钛矿微板的优异性能。使用微区瞬态光谱学和有限差分时域模拟的详细研究验证了，微板内混合的低维 RP 钙钛矿（作为包层）为高维 RP 钙钛矿（作为活性增益介质）提供了增强的激子和光子限制。此外，建立了结构-激光阈值关系（即，关联单个微板内低维 RP 钙钛矿的含量），这对于设计和性能优化至关重要。这些准二维 RP 钙钛矿微板也可以实现双波长激光。这些独特的性质将 RP 钙钛矿微板区分开来，成为一类新的自组装多层平面波导增益介质，有利于开发高效的激光器。
