Yang Wei, Chen Xiangyu, Yuan Mingqian, Geng Zhiming, Zhao Hongyuan, Wang Huan, Zeng Zhongle, Chai Nianyao, Yue Yunfan, Zhao Fengyi, Li Sheng, Lu Minghui, Chen Yanfeng, Yan Xuejun, Wang Xuewen
Opt Lett. 2024 Sep 15;49(18):5316-5319. doi: 10.1364/OL.528447.
Two-dimensional (2D) perovskites exhibit enhanced thermal stability compared to three-dimensional perovskites, especially the emerging 2D Dion-Jacobson (DJ) phase perovskite. However, the heat transfer mechanisms in DJ phase perovskites are rarely reported. Herein, we determine thermal conductivities of (PDA)(FA)n PbnI films with n = 1-6 by time-domain thermoreflectance. The measured results indicate that the thermal conductivities of these films are extremely low, showing a trend from decline to rise with increasing n values, and reaching to the lowest when n = 2. We measure the propagation of acoustic phonons in films with n = 1-3 by time-domain Brillouin scattering and find phonon velocity plays a key role in the thermal conductivity, which can be explained by the mismatch of spring constants between the inorganic layer and the organic layer using the bead-spring model. The gradually increasing thermal conductivity for larger n values is attributed to the gradual transformation of the grain orientation from horizontal to vertical, which is demonstrated by the grazing-incidence wide-angle x ray scattering (GIWAXS) results. Our work deepens the understanding of the thermal transport process in 2D DJ phase perovskite films and provides insights into thermal management solutions for their devices.
与三维钙钛矿相比，二维（2D）钙钛矿具有更高的热稳定性，尤其是新兴的二维狄龙 - 雅各布森（DJ）相钙钛矿。然而，关于DJ相钙钛矿中的热传递机制的报道很少。在此，我们通过时域热反射法测定了n = 1 - 6时（PDA）（FA）n PbnI 薄膜的热导率。测量结果表明，这些薄膜的热导率极低，随着n值的增加呈现出先下降后上升的趋势，并且在n = 2时达到最低。我们通过时域布里渊散射测量了n = 1 - 3的薄膜中声子的传播，发现声子速度在热导率中起关键作用，使用珠簧模型可以通过无机层和有机层之间弹簧常数的不匹配来解释这一点。对于较大的n值，热导率逐渐增加归因于晶粒取向从水平到垂直的逐渐转变，掠入射广角X射线散射（GIWAXS）结果证明了这一点。我们的工作加深了对二维DJ相钙钛矿薄膜热传输过程的理解，并为其器件的热管理解决方案提供了见解。
