Improving Performance of Organic-Silicon Heterojunction Solar Cells Based on Textured Surface via Acid Processing

Poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS) is widely applied in organic-photoelectronic devices due to its excellent transparency and conductivity. However, when it is used in the organic-silicon heterojunction solar cells with traditional pyramid texturing surface, the device performance is limited by the contact between the PEDOT:PSS and silicon wafer at the bottom of the pyramids. We optimized the structure of the bottom of the pyramids via acid isotropic etching (AIE) method with mixed acid solution to ensure that the silicon wafer is fully covered by the PEDOT:PSS. In addition, hydrogenated amorphous silicon thin films were deposited with PEVCD method as the passivation and back surface field (BSF) layer to decrease the rear surface recombination rate, thus increasing the long wavelength response. Finally, a power conversion efficiency of 13.78% was achieved after depositing MoO₃ on the front of the device as the antireflection layer

Novel Combination of Efficient Perovskite Solar Cells with Low Temperature Processed Compact TiO₂ Layer via Anodic Oxidation

In this work, a facile and low temperature processed anodic oxidation approach is proposed for fabricating compact and homogeneous titanium dioxide film (AO-TiO₂). In order to realize morphology and thickness control of AO-TiO₂, the theory concerning anodic oxidation (AO) is unveiled and the influence of relevant parameters during the process of AO such as electrolyte ingredient and oxidation voltage on AO-TiO₂ formation is observed as well. Meanwhile, we demonstrate that the planar perovskite solar cells (p-PSCs) fabricated in ambient air and utilizing optimized AO-TiO₂ as electron transport layer (ETL) can deliver repeatable power conversion efficiency (PCE) over 13%, which possess superior open-circuit voltage (Voc) and higher fill factor (FF) compared to its counterpart utilizing conventional high temperature processed compact TiO₂ (c-TiO₂) as ETL. Through a further comparative study, it is indicated that the improvement of device performance should be attributed to more effective electron collection from perovskite layer to AO-TiO₂ and the decrease of device series resistance. Furthermore, hysteresis effect about current density–voltage (<i>J</i>–<i>V</i>) curves in TiO₂-based p-PSCs is also unveiled