ZnO layer was modified with the addition of Cationic dyes including Crystal Violet (CV)/Ethyl violet (EV) in sol–gel process for an electron transport layer in inverted polymer solar cells (PSCs). X-ray photoelectron spectra showed the presence of CV/EV at the top of ZnO surface. Besides, oxygen defect was significantly reduced by CV/EV modification due to the chloride occupation. Furthermore, the amount of CV/EV decreased progressively from ZnO surface to bottom, being evidenced by depth profile. With modification, the ZnO surface became smoother and more hydrophobic to improve the contact with active layer. Meanwhile, CV/EV participated in the crystallization which resulted in the larger ZnO crystal grain size. Interface dipole after modification would slightly reduce the work function of ZnO and the energy barrier between ZnO and active layer via Ultraviolet Photoelectron Spectroscopy and External Quantum Efficiency analysis. Accordingly, inverted PSCs possessed better morphology, better electron extraction ability with ZnO modified by CV and EV respectively, rendering the power conversion efficiency up to 8.80% and 9.06% in comparison to the pristine ZnO (7.59%). In conclusion, we demonstrate a facile way to improve morphological and electrical properties of ZnO layer by simply adding CV/EV in sol–gel ZnO to fabricate high performance PSCs.

ZnO层在溶胶-凝胶工艺中加入了包括结晶紫（CV）/乙基紫（EV）在内的阳离子染料进行了改性，以用于倒置聚合物太阳能电池（PSC）中的电子传输层。X射线光电子能谱显示ZnO表面顶部存在CV / EV。此外，由于氯化物的占用，通过CV / EV改性显着减少了氧气缺陷。此外，CV / EV的量从ZnO表面到底部逐渐减小，这由深度分布证明。经过修饰，ZnO表面变得更光滑，更疏水，从而改善了与活性层的接触。同时，CV / EV参与了结晶，这导致了更大的ZnO晶粒尺寸。通过紫外光电子能谱和外部量子效率分析，改性后的界面偶极子会稍微降低ZnO的功函数以及ZnO与活性层之间的能垒。因此，分别用CV和EV改性的ZnO，倒置的PSC具有更好的形态，更好的电子提取能力，与原始ZnO（7.59％）相比，功率转换效率高达8.80％和9.06％。总之，我们证明了通过简单地在溶胶-凝胶ZnO中添加CV / EV来制备高性能PSC的方法，即可轻松改善ZnO层的形貌和电学性能。分别用CV和EV改性的ZnO具有更好的电子提取能力，与原始ZnO（7.59％）相比，功率转换效率分别高达8.80％和9.06％。总之，我们证明了通过简单地在溶胶-凝胶ZnO中添加CV / EV来制备高性能PSC的方法，即可轻松改善ZnO层的形貌和电学性能。分别用CV和EV改性的ZnO具有更好的电子提取能力，与原始ZnO（7.59％）相比，功率转换效率分别高达8.80％和9.06％。总之，我们证明了通过简单地在溶胶-凝胶ZnO中添加CV / EV来制备高性能PSC的方法，即可轻松改善ZnO层的形貌和电学性能。