昆明理工陳江照Adv. Sci.：效率25.46%！小分子MSR多級調控策略實現高性能鈣鈦礦太陽能電池

發表時間：2024-12-16 13:32

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主要內容

鈣鈦礦太陽能電池（PSCs）被視為下一代光伏技術的理想候選者，然而，其廣泛應用卻面臨著諸多挑戰，包括無法控制的快速結晶、陷阱輔助的非輻射復合以及低效的電荷傳輸等。為了克服這些難題，昆明理工大學陳江照教授等帶領其團隊提出了一種創新的多級調控（MSR）策略。該策略的核心在于將具有多個活性位點的小分子——1-[雙(三氟甲磺酰)甲基]-2,3,4,5,6-五氟苯（TFSP）巧妙地引入鈣鈦礦薄膜的前驅體溶液中。通過加入TFSP，成功地延緩并精細調控了鈣鈦礦薄膜的結晶和生長過程，從而形成了更大的晶粒，顯著減少了缺陷，并大幅提高了自組裝分子的覆蓋率，進而實現了高效的電荷傳輸。此外，TFSP的多個活性位點使其與鈣鈦礦薄膜中未配位的缺陷產生了強烈的結合親和力，而其高氟含量則賦予了其強烈的電負性，進一步增強了鈣鈦礦薄膜與電子傳輸層之間的結合強度。

*終，采用MSR策略制備的鈣鈦礦太陽能電池展現出了高達25.46%的**光電轉換效率（PCE），并且在非封裝條件下、相對濕度為45%的環境中，經過長達3000小時的測試后，仍保持了初始PCE的91.16%。這一**的結果充分驗證了所提出的多級調控策略的有效性。它不僅顯著改善了鈣鈦礦太陽能電池（PSC）的結晶度、抑制了缺陷、增強了界面接觸并降低了能級失配，從而大幅提升了PSC的性能，還展現出了更優的質量和穩定性，降低了層間載流子損失和非輻射復合強度，并加快了界面載流子提取速度。因此，所提出的多級調控策略無疑為提升鈣鈦礦光伏器件的性能并推動其更廣泛應用提供了一種新穎且簡便的方法。

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 at V = 0.9 V. e) Dark I–V curves for hole-only (ITO/MeO-4PACz/perovskite/Ag) devices based on the control and target PSCs. f) Influence of the light intensity on VOCof 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.

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