南京大学谭海仁研究员团队在Nature Energy期刊发表题为“Scalable fabrication of wide-bandgap perovskites using green solvents for tandem solar cells”的研究论文，团队成员段晨阳为论文第一作者，谭海仁研究员为论文通讯作者。
核心亮点：本文提出了一种由二甲亚砜和乙腈组成的绿色溶剂体系，可有效地溶解铯和溴盐，并添加乙醇以防止前驱体降解并延长溶液处理窗口。所采用刮涂法所制备的宽带隙太阳能电池获得了功率转换效率分别为19.6% （1.78 eV）和21.5% （1.68 eV）。同时，面积为20.25 cm2的全钙钛矿串联太阳能组件功率转换效率为23.8%。
钙钛矿基串联的商业化需要环保溶剂来可扩展地制造高效的宽带隙（WBG） （1.65-1.80 eV）钙钛矿。然而，由于铯和溴盐的溶解度较低，导致WBG钙钛矿依赖于有毒的N，N-二甲基甲酰胺溶剂，因此开发的用于甲脒型铅碘~1.50 ev带隙钙钛矿的绿色溶剂不适合WBG钙钛矿。基于此，南京大学谭海仁研究员团队提出了一种高效环保的绿色溶剂体系，通过混合DMSO、乙腈和乙醇来溶解铯和溴化盐，以防止前驱体降解，并延长加工窗口，在大面积上形成致密和无空隙的钙钛矿薄膜，从而提高WBG钙钛矿制造的规模。使用这种绿色溶剂混合物，获得了功率转换效率分别为19.6% （1.78 eV）和21.5% （1.68 eV）的刮涂WBG钙钛矿太阳能电池。在1cm2的全钙钛矿和钙钛矿/硅串联太阳能电池中分别实现了26.3%和27.8%的PCE。全钙钛矿串联太阳能组件（孔径面积为20.25 cm2），实现了23.8%的PCE。此外，绿色溶剂系统还可以在环境空气中制造WBG PSCs， PCE下降可以忽略不计，20.25cm2的全钙钛矿串联模块的PCE达到了23.1%。最后，绿色溶剂系统被证明适用于NBG PSC制造，使我们能够仅使用绿色溶剂为WBG和NBG亚电池生产20.25 cm2的全钙钛矿串联模块，PCE为22.2%。
Fig. 1 | Solvents and colloid properties of the EtOH-incorporated perovskite precursor solution. a, Safety, health and environment impact of solvents outlined by CHEM21. b, Vapour pressure and AN of the three studied solvents and DN of iodide and bromide ions. c, Colloidal size distribution of WBG perovskite precursor solution in multiple solvent systems. d, UV–vis absorption spectra of PbI2 dissolved in DMF/DMSO and in DMSO/ACN with various volumes of EtOH. e, FTIR spectra of DMSO/EtOH solvent, perovskite in DMSO/EtOH solution, perovskite in DMSO solution. f, Schematic illustration of the colloidal components after adding EtOH into the perovskite precursor solution. g, Pictures of one-month-aged 1.78 eV WBG precursors dissolved in DMSO/ACN and DMSO/ACN/EtOH solvent systems. h, 1H NMR spectra of only solvents [DMSO-d6/ACN-d3/EtOH], DMSO-d6/ACN-d3-based perovskite solution and DMSO-d6/ACN-d3/EtOHbased perovskite solution. The H corresponding to the position is marked in red. δ is the chemicalshift.
Fig. 2 | Crystallization kinetics of blade-coated perovskite films. a, log(v) − log(t) plot of perovskite film deposition from three different solvent systems. Each error bar is statistically derived from three sets of experimental data. The dashed lines represent the fitted lines of each solvent systems. b, XRD patterns and FWHM of wet perovskite films fabricated by blade coating at 9.5 mm s−1 with 40 kPa gas blowing followed by natural drying for 180 s. The arrow shows the change of FWHM after EtOH existence. c–e, Microscopy photographs of the corresponding perovskite films as described in b and top-view scanning electron microscope (SEM) images (insets) of WBG perovskite films peeled off from indium tin oxide (ITO) glass substrate to evaluate perovskite–substrate interface.
Fig. 3 | Characterization of WBG perovskite films fabricated utilizing the three solvent systems. a, XRD patterns of FA0.65Cs0.35PbI1.8Br1.2 perovskite films. b,c, PL and time-resolved photoluminescence spectra excited from the perovskite side of blade-coated WBG perovskite films. PL counts (norm.) indicates normalized PL counts. d–f, PL mapping images of a 1.5-cm-by-1.5-cm area of blade-coated WBG perovskite films.
Fig. 4 | Photovoltaic performance of 1.78 eV and 1.68 eV WBG PSCs prepared utilizing different solvent systems. a–c, Comparison of PCE (a), J–V curves (b) and EQE spectra (c) of 1.78 eV bandgap perovskite devices. d–f, Comparison of PCE (d), J–V curves (e) and EQE spectra (f) of 1.68 eV bandgap perovskite devices. The fitted curve from a and d follows a Gaussian distribution.
Fig. 5 | Photovoltaic performance of all-perovskite tandem solar cells and large-area perovskite tandem modules. a, Histogram of PCEs for 30 allperovskite tandem devices and a picture of 1-cm2 monolithic all-perovskite tandem solar cells. The fitted curve follows a Gaussian distribution. b, J–V curves of the champion all-perovskite tandem solar cells based on 1.78-eV WBG subcells (aperture area of 1.05 cm2). c,d, J–V (c) and EQE (d) curves of the champion all-perovskite tandem module (aperture area of 20.25 cm2, eight subcells in series). e, J–V curves of champion all-perovskite tandem module with WBG fabricated in ambient air (30% RH, aperture area of 20.25 cm2, eight subcells in series). f, J–V curves of all green solvent-based champion all-perovskite tandem module (aperture area of 20.25 cm2, eight subcells in series).
本文来源：DOI: 10.1038/s41560-024-01672-x
https://doi.org/10.1038/s41560-024-01672-x