Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Department of Chemistry, Columbia University , New York, New York 10027, United States.
ACS Nano. 2016 Aug 23;10(8):7963-72. doi: 10.1021/acsnano.6b03916. Epub 2016 Jul 25.
Lead halide perovskite nanowires (NWs) are emerging as a class of inexpensive semiconductors with broad bandgap tunability for optoelectronics, such as tunable NW lasers. Despite exciting progress, the current organic-inorganic hybrid perovskite NW lasers suffer from limited tunable wavelength range and poor material stability. Herein, we report facile solution growth of single-crystal NWs of inorganic perovskite CsPbX3 (X = Br, Cl) and their alloys [CsPb(Br,Cl)3] and a low-temperature vapor-phase halide exchange method to convert CsPbBr3 NWs into perovskite phase CsPb(Br,I)3 alloys and metastable CsPbI3 with well-preserved perovskite crystal lattice and NW morphology. These single crystalline NWs with smooth end facets and subwavelength dimensions are ideal Fabry-Perot cavities for NW lasers. Optically pumped tunable lasing across the entire visible spectrum (420-710 nm) is demonstrated at room temperature from these NWs with low lasing thresholds and high-quality factors. Such highly efficient lasing similar to what can be achieved with organic-inorganic hybrid perovskites indicates that organic cation is not essential for light emission application from these lead halide perovskite materials. Furthermore, the CsPbBr3 NW lasers show stable lasing emission with no measurable degradation after at least 8 h or 7.2 × 10(9) laser shots under continuous illumination, which are substantially more robust than their organic-inorganic counterparts. The Cs-based perovskites offer a stable material platform for tunable NW lasers and other nanoscale optoelectronic devices.
卤铅钙钛矿纳米线（NWs）作为一类廉价半导体，具有宽的带隙可调谐性，可用于光电等领域，如可调谐 NW 激光器。尽管取得了令人兴奋的进展，但目前的有机-无机杂化钙钛矿 NW 激光器受到可调谐波长范围有限和材料稳定性差的限制。在此，我们报告了简便的溶液生长方法，可制备出单晶 NWs 的无机钙钛矿 CsPbX3（X = Br，Cl）及其合金[CsPb（Br，Cl）3]，以及低温气相卤化物交换方法，可将 CsPbBr3 NWs 转化为钙钛矿相 CsPb（Br，I）3 合金和亚稳的 CsPbI3，同时保持钙钛矿晶格和 NW 形态完好无损。这些具有光滑端面和亚波长尺寸的单晶 NWs 是 NW 激光器的理想法布里-珀罗腔。通过光学泵浦，在室温下从这些 NWs 中实现了整个可见光谱（420-710nm）的可调谐激光，其激光阈值低，品质因数高。这种高效激光类似于有机-无机杂化钙钛矿所能实现的激光，表明有机阳离子对于这些卤铅钙钛矿材料的发光应用并非必需。此外，CsPbBr3 NW 激光器在连续照明下至少 8 小时或 7.2×10(9)次激光脉冲后，仍能稳定地发射激光，且没有可测量的退化，其稳定性远高于有机-无机钙钛矿。Cs 基钙钛矿为可调谐 NW 激光器和其他纳米尺度光电器件提供了稳定的材料平台。
