Perovskite grain wrapping by converting interfaces and grain boundaries into robust and water-insoluble low-dimensional perovskites

Abstract

Stabilizing perovskite solar cells requires consideration of all defective sites in the devices. Substantial efforts have been devoted to interfaces, while stabilization of grain boundaries received less attention. Here, we report on a molecule tributyl(methyl)phosphonium iodide (TPI), which can convert perovskite into a wide bandgap one-dimensional (1D) perovskite that is mechanically robust and water insoluble. Mixing TPI with perovskite precursor results in a wrapping of perovskite grains with both grain surfaces and grain boundaries converted into several nanometer-thick 1D perovskites during the grain formation process as observed by direct mapping. The grain wrapping passivates the grain boundaries, enhances their resistance to moisture, and reduces the iodine released during light soaking. The perovskite films with wrapped grains are more stable under heat and light. The best device with wrapped grains maintained 92.2% of its highest efficiency after light soaking under 1-sun illumination for 1900 hours at 55°C open-circuit condition.

Critical role of 1D materials in realizing efficient and stable perovskite solar cells

“…In order to ameliorate the situation, Jiao and co-authors introduced tributyl(methyl)phosphonium iodide (TPI) into a 3D perovskite precursor solution to convert perovskite GBs to 1D perovskite. 80 As exhibited in Fig. 2a and b, the TPPbI 3 powder had no clear color change aer 12 h water soaking, while the MAPbI 3 changed to yellow just within 10 s, which demonstrated that the 1D TPPbI 3 perovskite had strong water resistance, which could protect the 3D perovskite from the moisture invade.…”

“…Fig.2(a) Picture of 3D perovskite powder before and after soaking in water for 10 s. (b) Picture of 1D/3D perovskite powder before and after soaking in water for 12 h 80. Copyright 2022, Science.…”

Spidermen Strategy for Stable 24% Efficiency Perovskite Solar Cells

“…[16,17] Therefore, the interface engineering strategy is an effective idea to improve photoelectric performance. [18,19] The nonradiative recombination affects the carrier mobility and PCE of devices, owing to both charge transport layer and perovskite surface defects. [20] Therefore, the process of carrier transport is extensively studied at each layer.…”

“…[ 16,17 ] Therefore, the interface engineering strategy is an effective idea to improve photoelectric performance. [ 18,19 ]…”

Surface lattice enhancement of red-emitting fluorides enabled by embedding small cations

“…[18][19][20][21][22][23][24] For example, Huang et al transformed the surface and grain boundaries of chalcogenide particles into a few nanometer thick, high mechanical strength and water-insoluble low-dimensional perovskite, which showed a significantly enhanced moisture-proof property and photothermal stability. 25 In recent years, a lot of work has been reported on the construction of core-shell structures to address the problem of low moisture resistance of Mn 4+ doped fluorides. [26][27][28][29][30][31] The direct reduction method can remove Mn 4+ from the surface and thus form a very thin Mn-free host shell on the fluoride particles.…”