Tailoring Low-Dimensional Phases for Improved Performance of 2D–3D Tin Perovskite Solar Cells

Abstract

2D−3D tin perovskites are considered as promising candidates for realizing efficient lead-free perovskite solar cells (PSCs). However, the ultrathin 2D phases could unfavorably affect charge transport and device performance. In the present work, we demonstrate that the introduction of Dhomoserine lactone hydrochloride (D-HLH) can tailor the lowdimensional phases and improve the quality of 2D−3D tin perovskite films. The functional group in D-HLH can interact with FA + and I − as well as Sn 2+ in the precursor solution. These interactions not only affect the formation of tin perovskite film and favor the formation of thicker 2D phases but also decrease the defect density and suppress the nonradiative recombination. As a result, the efficiency of tin PSCs is significantly improved from 7.97 to 12.45%, and the stability of the device is also enhanced. This work provides a feasible strategy to regulate the lowdimensional phases in 2D−3D tin PSCs toward realizing high efficiency.

Carrier Transport in Low‐Dimensional Tin Perovskite Solar Cells

“…Therefore, Wang et al introduced D‐homoserine lactone hydrochloride (D‐HLH) into the perovskite. [ 82 ] It was found that D‐HLH can significantly promote the formation of n = 3 perovskite and reduced the formation of n = 2 phase. The corresponding PCE can be increased from 7.97% to 12.45%.…”

Modulating Nucleation and Crystal Growth of Tin Perovskite Films for Efficient Solar Cells

“…Figure d shows the PL evolution of the films without and with urea during spin-coating. For the film without urea, upon antisolvent dripping at 18 s, the PL intensity of the perovskite film rises immediately due to the supersaturation change of the precursor solution. − Then there is an instant PL intensity drop within the next 4 s (18–22 s), corresponding to the reduction of the supersaturation caused by the antisolvent spinning-off and solute consumption. After 22 s, solvent evaporation results in an increase in supersaturation, and a large number of perovskite nuclei are formed in the film and continue to grow, leading to the red shift of the PL signal and continuously increased PL intensity. , For the sample with urea, after a drop of PL intensity, the rebound appears earlier and the PL is continuously more intensive than the control film during the spin-coating process (Figure S3), probably implying a faster nucleation and denser nuclei produced in the film.…”