Organic semiconductors as hole transport materials (HTMs) often require additives, such as LiTFSI and tert-butylpyridine (TBP), in order to enhance their hole conductivities. However, the combination of lithium salts and TBP leads to significant HTM morphological deformation and poor device stability. Here we have successfully applied tetrabutylammonium (TBA) salts to replace both LiTFSI and TBP. A high power conversion efficiency of 18.4% has been achieved for the devices with TBATFSI, which is higher than the control devices with LiTFSI and TBP (18.1%). We also found that the anions in the TBA salts play important roles in the hole conductivity and uniformity of the HTM layer, as well as the hysteresis of the devices. More importantly, the devices with TBATFSI and TBAPF₆ demonstrated significantly enhanced environmental and thermal stability. This new strategy of using TBA salts is promising for developing stable organic HTM thin films for solar cell applications.

中文翻译：

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用于高效钙钛矿太阳能电池的4-叔丁基吡啶无空穴传输材料：提高环境和热稳定性的新策略

作为空穴传输材料（HTM）的有机半导体通常需要添加剂，例如LiTFSI和叔丁基吡啶（TBP），以增强其空穴电导率。但是，锂盐和TBP的组合会导致显着的HTM形态变形和较差的器件稳定性。在这里，我们成功地应用了四丁基铵（TBA）盐代替LiTFSI和TBP。具有TBATFSI的设备已实现了18.4％的高功率转换效率，高于具有LiTFSI和TBP的控制设备（18.1％）。我们还发现，TBA盐中的阴离子在HTM层的空穴电导率和均匀性以及器件的磁滞中起重要作用。更重要的是，带有TBATFSI和TBAPF ₆的设备表现出显着增强的环境和热稳定性。使用TBA盐的新策略有望为太阳能电池应用开发稳定的有机HTM薄膜。