Modulating CsPbl₃ crystallization by using diammonium agent for efficient solar cells

Abstract

Cesium lead triiodide (CsPbI3) perovskite receives tremendous attention for photovoltaic applications, owing to its remarkable thermal stability and optoelectronic properties. However, realizing the CsPbI3 perovskite with high black‐phase stability and optoelectronic properties remains a significant challenge, which largely affects the photovoltaic performance of perovskite solar cells (PSCs). Herein, aromatic ammonium agents are used to modulate the crystallization of the CsPbI3 perovskite to improve its black‐phase stability and optoelectronic properties for efficient PSCs. Systemically experimental studies and comprehensively theoretical calculations are performed, which reveal that histammonium dihydrochloride (HACl2) could strongly couple with the perovskite during its crystallization, leading to faster nucleation and slower perovskite growth, and thus modulating the crystallization dynamics of the perovskites. Moreover, the residual diammonium cations (HA2+) distributed at the grain boundaries and on the surface of the perovskites can effectively passivate defects through electrostatic interactions, substantially suppressing trap‐assisted nonradiative recombination, and prompting more matched perovskite surface energetics. Consequently, the photovoltaic performance of CsPbI3 PSCs is largely improved because of a combination of enhanced crystallinity and optoelectronic properties of the perovskites. This work offers a new avenue to prepare inorganic perovskites with high optoelectronic properties for photovoltaics.

Influence of Donor Skeleton on Intramolecular Electron Transfer Amount for Efficient Perovskite Solar Cells

“…Upon the incorporation of additives, the recombination resistance (R rec ) in the low-frequency region increases (Figure 5f), with a more pronounced effect for benzenebridging molecule, indicating the suppressed defect-assisted nonradiative recombination owing to the reduced defects. [55,56] This can be further confirmed by the ideality factors closer to unit under open-circuit and short-circuit conditions simultaneously, [57] which are obtained by plotting V oc and J sc as a function of light intensity (Figure S16). As evidenced from Mott-Schottky measurements in Figure 5g, the built-in electric field (V bi ) of control device is determined to be 0.97 V, which is gradually increased to 1.23 V for the optimal device, an indicator of the enlarged driven force for charge extraction rather than annihilation in PSC.…”