Photovoltaic performance of novel Perovskite/organic integrated solar cells with high efficiency and high stability

Perovskite/organic integrated solar cell possesses the perovskite active layer with wide band gap that can absorb high energy photons, while the lower energy photons can pass through the perovskite layer and be absorbed by the organic active layer with narrow band gap. By introducing a Bulk heterojunction (BHJ) consisting of perovskite materials and near-infrared (NIR) organic semiconductor materials in the visible light region, the enhanced short-circuit current density of organic cells can be obtained while maintaining the high open-circuit voltage of perovskite-type devices. We prepare perovskite/organic integrated solar cells by directly deposing the narrow band gap organic active layer PC20BDTDPP:PC71BM on CH3NH3PbI3. The CH3NH3PbI3/ PC20BDTDPP:PC71BM integrated solar cell can widen the perovskite absorption spectra, thereby increasing the near-infrared light absorption. The results show that the short-circuit current density of the integrated solar cell increases to 23.90 mA/cm2, the optical response is widened to 920 nm, the external quantum efficiency reaches 85% in the visible region, and is close to 55% in the near infrared region (800 -900 nm), and the energy conversion efficiency of the device increases up to 20.30%. The integrated current density, quantum efficiency, and energy conversion efficiency of the best device are the highest values ever reported in perovskite/organic integrated solar cells. At room temperature of 25 celcius and humidity of 30%, the efficiency of the device decreases to 95% of the original efficiency after 350 h, showing excellent device stability. The results show that it is an effective method to improve the near-infrared absorption of perovskite solar cells and improve the performance of perovskite/organic integrated solar cells through material combination and device structure optimization. The present research provides theoretical guidance and experimental basis for the development of perovskite/ organic integrated cells with high efficiency and stability in the future.