主要内容
钙钛矿太阳能电池（PSCs）被视为下一代光伏技术的理想候选者，然而，其广泛应用却面临着诸多挑战，包括无法控制的快速结晶、陷阱辅助的非辐射复合以及低效的电荷传输等。为了克服这些难题，昆明理工大学 陈江照教授等带领其团队提出了一种创新的多级调控（MSR）策略。该策略的核心在于将具有多个活性位点的小分子——1-[双(三氟甲磺酰)甲基]-2,3,4,5,6-五氟苯（TFSP）巧妙地引入钙钛矿薄膜的前驱体溶液中。通过加入TFSP，成功地延缓并精细调控了钙钛矿薄膜的结晶和生长过程，从而形成了更大的晶粒，显著减少了缺陷，并大幅提高了自组装分子的覆盖率，进而实现了高效的电荷传输。此外，TFSP的多个活性位点使其与钙钛矿薄膜中未配位的缺陷产生了强烈的结合亲和力，而其高氟含量则赋予了其强烈的电负性，进一步增强了钙钛矿薄膜与电子传输层之间的结合强度。
最终，采用MSR策略制备的钙钛矿太阳能电池展现出了高达25.46%的最佳光电转换效率（PCE），并且在非封装条件下、相对湿度为45%的环境中，经过长达3000小时的测试后，仍保持了初始PCE的91.16%。这一卓越的结果充分验证了所提出的多级调控策略的有效性。它不仅显著改善了钙钛矿太阳能电池（PSC）的结晶度、抑制了缺陷、增强了界面接触并降低了能级失配，从而大幅提升了PSC的性能，还展现出了更优的质量和稳定性，降低了层间载流子损失和非辐射复合强度，并加快了界面载流子提取速度。因此，所提出的多级调控策略无疑为提升钙钛矿光伏器件的性能并推动其更广泛应用提供了一种新颖且简便的方法。
Figure 1
a) Reaction coordinate diagram of formation paths for different perovskite intermediates in DMF. b) Binding energies of MeO–4PACz dimer, MeO–4PACz tetramer, and MeO–4PACz dimer with TFSP. c) Interactions of different configurations of TFSP with the perovskite surface: i) perpendicular to the perovskite surface with the benzene ring above, ii) perpendicular to the perovskite surface with the benzene ring below, and iii) parallel to the perovskite surface; iv) side view of the interactions of TFSP (dashed ovals) with the Pb/I terminated (001) FAPbI3 surface. PbI6octahedra are highlighted to show that major structural relaxation was mostly observed in the uppermost layer. Changes in the charge-density profile around all species involved in the TFSP–surface binding include prominent charge accumulation (yellow) and depletion (blue) regions indicating F─Pb and O─Pb interactions. d) Binding of perovskite layers with and without TFSP to PCBM in the ETL.
Figure 2
Comparison between control and target films: a, b) in situ PL maps, c, d) in situ UV-vis intensity of 700 nm, e, f) top-view Scanning electron microscopy (SEM) images.
Figure 3
ToF-SIMS of a) control and b) target films. c, f) GIXRD with different ψ angles (10–50°) at a depth of ≈200 nm. 2D GIWAXS maps of d) control and e) target films. cAFM maps of g) control and h) target films. (i) Current as a function of distance for the control and target films obtained from the cAFM maps.
Figure 4
a) Projected density of states of the VI defective perovskite slab passivated without and with TFSP. Transient absorption (TA) spectra at different delay times for the b) control and c) target films. d) Steady-state PL spectra and e) TRPL decay curves of the control and target films. f) Ultraviolet photoelectron spectroscopy (UPS) spectra of secondary-electron cutoff (left) and valence band (right) regions for the control and target films. g) Energy-level alignment of ITO/MeO-4PACz/perovskite with and without TFSP/PCBM/Ag. g) TPV and h) TPC decay curves of control and target films.
Figure 5
a) Photocurrent density−voltage (J−V) curves and b) steady-state output of control and target PSCs with an active area of 0.043 cm2. c) External quantum efficiencies (EQE) spectra of control and target PSCs. d) Nyquist plots of the Electrical impedance spectra (EIS) for control and target PSCs atV= 0.9 V. e) DarkI–Vcurves for hole-only (ITO/MeO-4PACz/perovskite/Ag) devices based on the control and target PSCs. f) Influence of the light intensity onVOCof PSCs. Energy profiles of Pb2+and I−ion migration in g) control and h) target PSCs. The structures of the nudged elastic band (NEB) images in the initial, transition and final states are shown. i) Normalized PCE decay of control and target PSCs stored in ambient air.
文献信息
Multistage Regulation Strategy via Fluorine-Rich Small Molecules for Realizing High-Performance Perovskite Solar Cells
Xiong Chang,Kunpeng Li,Yong Han,Guohua Wang,Zhishan Li,Dongfang Li,Fashe Li,Xing Zhu,Hua Wang,Jiangzhao Chen,Tao Zhu
https://onlinelibrary.wiley.com/doi/10.1002/advs.202412557
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