主要內(nèi)容

在鈣鈦礦太陽能電池（PVSCs）的研究中，鈣鈦礦材料與電子傳輸層之間的界面復(fù)合和離子遷移問題一直是阻礙其效率和穩(wěn)定性進(jìn)一步提升的關(guān)鍵因素。為了突破這一瓶頸，香港城市大學(xué) Alex K.-Y. Jen（任廣禹）教授及其研究團(tuán)隊開創(chuàng)性地提出了一種創(chuàng)新的界面橋接策略。他們精心設(shè)計了一系列分子可調(diào)簇作為中間層，這些簇能夠同時與C60和鈣鈦礦材料形成強(qiáng)烈的相互作用。并且分子可調(diào)簇具備幾個顯著特性：結(jié)構(gòu)**可控、電荷載流子遷移率高、溶解度適宜以及能級匹配良好。這些特性使它們能夠有效地鈍化鈣鈦礦的表面缺陷，并在其表面形成一層緊密且均勻的覆蓋層，從而牢固地固定C60。特別值得一提的是，研究團(tuán)隊引入了含有不同氟取代基的團(tuán)簇，如CTOCPh-5F，其中五氟苯基不僅與鈣鈦礦表面的終止基團(tuán)產(chǎn)生了強(qiáng)烈的靜電相互作用，還表現(xiàn)出顯著的四極相互作用，進(jìn)一步增強(qiáng)了與C60的結(jié)合力。

采用這種創(chuàng)新設(shè)計后，研究團(tuán)隊所制備的反式PVSCs實現(xiàn)了高達(dá)25.6%的光電轉(zhuǎn)換效率（PCE），且這一高效性能是在未進(jìn)行額外表面鈍化處理的情況下取得的。更為關(guān)鍵的是，這些未封裝的器件在光照、加熱和偏置條件下展現(xiàn)出了出色的穩(wěn)定性。在**功率點跟蹤測試進(jìn)行了1500小時后，它們?nèi)员３至顺跏糚CE的98%。這一結(jié)果充分驗證了該界面橋接策略在提升鈣鈦礦太陽能電池效率和穩(wěn)定性方面的顯著成效。

綜上所述，本研究為開發(fā)高效鈣鈦礦光伏電池提供了全新的**界面材料設(shè)計思路和方法，展現(xiàn)出了廣闊的應(yīng)用前景。未來，通過不斷優(yōu)化分子可調(diào)簇的結(jié)構(gòu)和性質(zhì)，研究團(tuán)隊有望推動鈣鈦礦太陽能電池實現(xiàn)更高的效率和更**的穩(wěn)定性。

Fig. 1. Crystal structures and properties of the clusters.

(A) Molecular structure of the CTOCPh, CTOCPh-F, and CTOCPh-5F clusters with top and side views, extracted from the single-crystal files. Chartreuse, Ti; red, O; gray, C; green, F. (B) Electron mobility of the clusters. (C) Schematic representation of the band edge positions of the clusters and perovskite based on values from UPS results, referenced to the vacuum level. EF and EVAC represent Fermi and vacuum levels, respectively. (D) HAADF-STEM image coupled with the modeling of the CTOCPh-5F clusters.

Fig. 2. The interaction between clusters, perovskite, and C60.

(A to D) Calculated binding energy (Ebinding) for (A) PbI2-rich FAPbI3 (100)/CTOCPh, (B) PbI2-rich FAPbI3 (100)/CTOCPh-F, (C) PbI2-rich FAPbI3 (100)/CTOCPh-5F, and (D) CTOCPh-5F/C60. The green dashed circle marked the connection between the perovskite and the fluorine on the benzene ring. The DFT calculations were performed at the GGA/PBE+vdW level. (E and F) The XPS spectra of (E) Pb 4f and (F) I 3d of the perovskite films with and without CTOCPh-5F coating. (G) 19F solid-state NMR spectra of the pure CTOCPh-5F cluster, the mixture of CTOCPh-5F and perovskite, and the mixture of CTOCPh-5F and C60, respectively. The peaks corresponding to the pentafluorophenyl group are marked in stars. The dashed lines in (E), (F), and (G) are purely for visual guidance and do not convey any specific meaning.

Fig. 3. Device performance.

(A) Schematic illustration of the CTOCPh-5F interlayer in the device from the top view and side view. (B) Box plots of the PCE of bare perovskite and CTOCPh-, CTOCPh-F–, and CTOCPh-5F–coated PVSCs, respectively. (C) J-V characteristics of the champion devices. Inset is the stable power output (SPO) of the device. (D) Operational stability of the PVSCs under MPP tracking. (E) Evolution of the device performance under heating at 85°C.

Fig. 4. Stability assessment.

(A to D) AFM topography images of the pristine [(A) and (B)] and aged [(C) and (D)] films. (E and F) Surface potential mapping of the aged (E) perovskite/C60 film and (F) perovskite/CTOCPh-5F/C60 film. The red circles in (C) and (E) indicate examples of C60 aggregation after aging. (G and H) Pb 4f and I 3d XPS spectra of the (G) perovskite/C60 film and (H) perovskite/CTOCPh-5F/C60 film before and after aging. (I and J) XPS depth profile analysis of the aged devices (I) without and (J) with CTOCPh-5F coating layer.

文獻(xiàn)信息

Molecularly tailorable metal oxide clusters ensured robust interfacial connection in inverted perovskite solar cells

Fengzhu Li , Chaowei Zhao   , Yanxun Li , Zhen Zhang, Xiaofeng Huang, Yuefeng Zhang, Jie Fang, Tieyuan Bian , Zhiyuan Zeng , Jun Yin , and Alex K.-Y. Jen

https://www.science.org/doi/full/10.1126/sciadv.adq1150

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