Interlayer materials play a critical role in fabricating highly stable organic solar cells (OSCs). Here, we design a cross-linkable naphthalene diimide (NDI) derivative to prepare a robust and hydrophobic electron transporting interlayer for OSCs. A non-polar electron donor PCy₂ is elaborately selected to n-dope the crosslinked c-NDI:PCy₂ film, by which the doping density of c-NDI:PCy₂ is increased by five times to obtain a high conductivity of 6.51 × 10⁻³ S/m. Meanwhile, the strong hydrophobicity of c-NDI:PCy₂ effectively protects the device against water ingress, endowing OSCs with excellent water resistance. A power conversion efficiency of 17.7% is obtained with the c-NDI:PCy₂ interlayer, representing the highest value for OSCs with an inverted device architecture. Strikingly, this OSC can be used underwater. By immersing the non-encapsulated cell in water, 70% of its initial efficiency is maintained after 1,000 h in the dark or 4 h under continuous illumination (100 mW/cm²).

中间层材料在制造高度稳定的有机太阳能电池 (OSC) 中起着至关重要的作用。在这里，我们设计了一种可交联的萘二酰亚胺 (NDI) 衍生物，为 OSC 制备坚固且疏水的电子传输夹层。精心选择非极性电子供体PCy _{2对交联的}c -NDI:PCy _{2薄膜进行}n掺杂，使c -NDI:PCy ₂的掺杂密度提高5倍，获得6.51 × 10 ^-3秒/米。同时， c -NDI:PCy ₂的强疏水性有效防止设备进水，赋予OSC优异的防水性能。使用c -NDI:PCy ₂夹层可获得 17.7% 的功率转换效率，代表具有倒置器件架构的 OSC 的最高值。引人注目的是，这个 OSC 可以在水下使用。通过将未封装的电池浸入水中，在黑暗中放置 1,000 小时或在连续照明 (100 mW/cm 2) 下放置 4 小时后，其初始效率可保持 70 ^%。