Hybrid Low‐Dimensional Phase Structure The presence of evenly distributed 3D‐like phases with vertical orientation can significantly facilitate charge transport and suppress charge recombination in the quasi‐2D perovskites‐based photodetector, outperforming the prevalent phase structure with a vertical dimension gradient. In article 2300216, Wanzhu Cai, Jian Qing, Guanhaojie Zheng, and co‐workers explore the correlation between quasi‐2D perovskites' phase structure and their charge transport properties. A combination of exceptional figures of merit is realized.

Quasi-two-dimensional (Q-2D) perovskites are emerging as one of the most promising materials for photodetectors. However, a significant challenge to Q-2D perovskites for photodetection is their insufficient charge transport ability, which is mainly attributed to their hybrid low-dimensional n-phase structure. This study demonstrates that evenly-distributed 3D-like phases with vertical orientation throughout the film can greatly facilitate charge transport and suppress charge recombination, outperforming the prevalent phase structure with a vertical dimension gradient. Based on such a phase structure, a Q-2D Ruddlesden−Popper perovskite self-powered photodetector achieving a combination of exceptional figures-of-merit is realized, including a responsivity of 0.45 AW −1 , a peak specific detectivity of 2.3 × 10 13 Jones, a 156 dB linear dynamic range, and a rise/fall time of 2.89 µs/1.93 µs. The desired phase structure is obtained by utilizing a double-hole transport layer (HTL), combining hydrophobic PTAA and hydrophilic PEDOT: PSS. Besides, the dependence of the hybrid low-dimensional phase structure is also identified on the surface energy of the buried HTL substrate. This study gives insight into the correlation between Q-2D perovskites' phase structure and performance, providing a valuable design guide for Q-2D perovskite-based photodetectors.

The 2D Ruddlesden–Popper perovskites (RPPs), consisting of alternating organic spacer layers and inorganic layers, are emerging photovoltaic materials because of their highly tunable optoelectronic properties and improved stability compared to their 3D counterparts. Nonhalide lead sources attract increasing attention in 3D perovskites, whereas the lead sources for RPPs are limited to lead halides. Herein, nonhalide lead source of lead acetate is investigated for high‐quality RPP films by a dimethyl sulfoxide (DMSO)‐assisted delayed annealing process. The incorporation of DMSO in the lead acetate–based precursor solution regulates the crystallization process, resulting in RPP films with distinctly enhanced crystallinity, reduced trap density, vertical crystal orientation, and graded phase distribution. Consequently, the optimized RPP solar cell with an inverted planar structure delivers a champion power conversion efficiency of 17.3%. Herein, future developments of nonhalide lead sources are spurred to fabricate RPP films with high device performance.