Photo-active heterojunctions were prepared by growing thin La_0.9Sr_0.1CrO_3-δ films on SrTiO₃ (STO) single crystals substrates via pulsed laser deposition. The photo-electrochemical characteristics of these heterojunctions under UV illumination were investigated by DC measurements and electrochemical impedance spectroscopy (EIS). Under UV illumination, the photo-current produced by these junctions increases over time by almost an order of magnitude to 1 to 2 mA cm^-2 at 350 °C. Two effects governing this increase can be distinguished: A first process, independent of the surrounding atmosphere, is related to a stoichiometry polarization of the STO single crystal upon current flow. A second process is highly sensitive to contaminants in the surrounding atmosphere and is strongly accelerated in pure, synthetic atmospheres. We suggest that it is related to photo-oxidation of the STO single crystal. EIS revealed that both processes result in a decrease of both the electronic transport resistance through the STO single crystal and, to a lesser degree, the space charge resistance of the photo-active junction. Operando EIS under illumination and with DC bias was used to record the cells' photo-power characteristics and identify individual loss processes. Owing to the illumination induced strong increase of the STO single crystal conductivity, the photo-currents of such enhanced cells are limited by the space charge resistance.

通过脉冲激光沉积在SrTiO _{3 (STO)单晶基底上生长薄La 0.9} Sr _0.1 CrO _3-δ薄膜来制备光敏异质结。通过直流测量和电化学阻抗谱（EIS）研究了这些异质结在紫外线照射下的光电化学特性。在紫外线照射下，这些结产生的光电流随着时间的推移几乎增加了一个数量级，在 350 °C 时达到 1 至 2 mA cm ^-2。可以区分控制这种增加的两种效应：第一个过程与周围大气无关，与电流流动时 STO 单晶的化学计量极化有关。第二个过程对周围大气中的污染物高度敏感，并且在纯净的合成大气中强烈加速。我们认为这与STO单晶的光氧化有关。EIS表明，这两个过程都会导致通过STO单晶的电子传输电阻降低，并在较小程度上降低光敏结的空间电荷电阻。在照明和直流偏压下使用 Operando EIS 来记录电池的光功率特性并识别单个损耗过程。由于光照引起STO单晶电导率的强烈增加，这种增强型电池的光电流受到空间电荷电阻的限制。