Tip-Induced Strain Engineering of a Single Metal Halide Perovskite Quantum Dot
Hyeongwoo Lee, Ju Young Woo, Dae Young Park, Inho Jo, Jusun Park, Yeunhee Lee, Yeonjeong Koo, Jinseong Choi, Hyojung Kim, Yong‐Hyun Kim, Mun Seok Jeong, Sohee Jeong, Kyoung‐Duck Park
Abstract
Strain engineering of perovskite quantum dots (pQDs) enables widely tunable photonic device applications. However, manipulation at the single-emitter level has never been attempted. Here, we present a tip-induced control approach combined with tip-enhanced photoluminescence (TEPL) spectroscopy to engineer strain, bandgap, and the emission quantum yield of a single pQD. Single CsPbBrxI3–x pQDs are clearly resolved through hyperspectral TEPL imaging with ∼10 nm spatial resolution. The plasmonic tip then directly applies pressure to a single pQD to facilitate a bandgap shift up to ∼62 meV with Purcell-enhanced PL increase as high as ∼105 for the strain-induced pQD. Furthermore, by systematically modulating the tip-induced compressive strain of a single pQD, we achieve dynamical bandgap engineering in a reversible manner. In addition, we facilitate the quantum dot coupling for a pQD ensemble with ∼0.8 GPa tip pressure at the nanoscale estimated theoretically. Our approach presents a strategy to tune the nano-opto-electro-mechanical properties of pQDs at the single-crystal level.