The performance of ZnO-based dye-sensitized solar cells (DSSCs) has always been lower than that of TiO₂-based devices, however, the factors for this difference are still not entirely understood. Here we use current - voltage curves in combination with intensity-modulated photovoltage spectroscopy, charge extraction measurements, and surface photovoltage spectroscopy to gain insight in the photochemical charge separation in ZnO-based DSSCs. Devices were fabricated with electrodeposited nanostructured, mesoporous ZnO films, an organic fluorenyl-thiophene dye (OD-8) as sensitizer, and an electrolyte solution with either the I⁻/I₃⁻ or [Co(2,2′-bipyridyl)₃]^2+/3+ redox couple. Surface photovoltage measurements and scanning electron microscopy images show that Zn²⁺-dye aggregates are most likely the cause of a decrease in cell performance with sensitization times longer than 4 h, due to the relatively acidic acrylonitrile bonding moiety of the OD-8 dye. Charge extraction measurements combined with intensity-modulated photovoltage spectroscopy illustrate that a lower electron lifetime for the DSSCs with the [Co(2,2′-bipyridyl)₃]^2+/3+ redox couple prevents achieving the thermodynamically attainable photovoltage, thus limiting solar cell efficiency. It can be concluded that further improvements in ZnO-based DSSCs are possible by: (i) avoiding the formation of Zn²⁺-dye aggregates in the mesoporous structure; (ii) preventing back electron transfer from ZnO to the electron acceptor in the electrolyte solution.

ZnO基染料敏化太阳能电池（DSSC）的性能一直低于TiO ₂基器件的性能，但是，造成这种差异的因素仍不完全清楚。在这里，我们将电流-电压曲线与强度调制的光电压光谱，电荷提取测量和表面光电压光谱结合使用，以了解基于ZnO的DSSC中的光化学电荷分离。设备用电解制造纳米结构化的中孔氧化锌薄膜，有机芴基噻吩染料（OD-8）作为敏化剂，并与I电解液^- / I ₃ ^-或[Co（2,2'-联吡啶）₃ ] ^{2 + / 3 +}氧化还原夫妇。表面光电压测量和扫描电子显微镜图像显示，Zn 2 ^+-染料聚集体最有可能是导致细胞性能下降的原因，其感光时间长于4 h，这归因于OD-8染料的相对酸性的丙烯腈键合部分。电荷提取测量与强度调制的光电压光谱相结合表明，具有[Co（2,2'-bipyridyl）₃ ] ^{2 + / 3 +}氧化还原对的DSSC的较低电子寿命会阻止实现热力学上可达到的光电压，从而限制了太阳能电池效率。可以得出结论，通过以下方式可以进一步改善基于ZnO的DSSC：（i）避免形成Zn ²⁺-染料在中孔结构中聚集；（ii）防止在电解质溶液中从ZnO向电子受体的反向电子转移。