Tsai I-Hua, Narra Sudhakar, Bhosale Sumit S, Diau Eric Wei-Guang
J Phys Chem Lett. 2023 Mar 16;14(10):2580-2587. doi: 10.1021/acs.jpclett.3c00333. Epub 2023 Mar 7.
We report time-resolved spectral properties of highly stable and efficient red-emitting hybrid perovskite nanocrystals with the composition FAMAPbBrI (FAMA PeNC) synthesized by using the hot-addition method. The PL spectrum of the FAMA PeNC shows a broad asymmetric band covering 580 to 760 nm with a peak at 690 nm which can be deconvoluted into two bands corresponding to the MA and FA domains. The interactions between the MA and FA domains are shown to affect the relaxation dynamics of the PeNCs from the subpicosecond to tens of nanoseconds scale. Time-correlated single-photon counting (TCSPC), femtosecond PL optical gating (FOG), and femtosecond transient absorption spectral (TAS) techniques were employed to study the intercrystal energy transfer (photon recycling) and intracrystal charge transfer processes between the MA and the FA domains of the crystals. These two processes are shown to increase the radiative lifetimes for the PLQYs exceeding 80%, which may play a key role in enhancing the performance of PeNC-based solar cells.
我们报道了通过热注入法合成的具有FAMAPbBrI（FAMA钙钛矿纳米晶）组成的高稳定性和高效红色发光混合钙钛矿纳米晶的时间分辨光谱特性。FAMA钙钛矿纳米晶的光致发光光谱显示出一个覆盖580至760nm的宽不对称带，峰值在690nm，该峰可解卷积为对应于MA和FA域的两个带。结果表明，MA和FA域之间的相互作用会影响钙钛矿纳米晶从亚皮秒到几十纳秒尺度的弛豫动力学。采用时间相关单光子计数（TCSPC）、飞秒光致发光光学门控（FOG）和飞秒瞬态吸收光谱（TAS）技术研究了晶体中MA和FA域之间的晶间能量转移（光子回收）和晶内电荷转移过程。结果表明，这两个过程增加了光致发光量子产率（PLQY）超过80%的辐射寿命，这可能在提高基于钙钛矿的太阳能电池性能方面起关键作用。
