All low-temperature processed carbon-based planar heterojunction perovskite solar cells employing Mg-doped rutile TiO2 as electron transport layer

• DOI: 10.1016/j.electacta.2018.07.044
• Publication Date: 2018-07-19T11:27:28Z
• Authors: Xingyue Liu; Zhiyong Liu; Bo Sun; Xianhua Tan; Haibo Ye; Yuxue Tu; Tielin Shi; Zirong Tang; Guanglan Liao
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract Electron transport layer (ETL), functioning as the electron transportation and extraction layer as well as hole-blocking layer, plays an important role in planar perovskite solar cells (PSCs). Majority of the state-of-the-art PSCs contain a TiO2 ETL always requiring a high temperature (500 °C) treatment, which is both energy-consuming and incompatible with flexible substrates, thus hindering large-scale application in flexible devices. Here, we demonstrated a low-temperature (70 °C) solution-processed Mg-doped rutile TiO2 as ETL in planar PSCs, while the thermal-evaporated copper phthalocyanine (CuPc) and doctor-bladed carbon were introduced as the hole transport layer (HTL) and counter electrode, respectively. The as-prepared PSC obtains a 15.73% power conversion efficiency (PCE), which is quite an excellent efficiency among carbon-based planar PSCs, getting an increase by 16% compared to the 13.56% PCE of the pristine TiO2-based device. The prominent increment is mainly attributed to the faster charge extraction, better electrical conductivity and suppressed charge recombination of Mg-doped TiO2. Besides, using highly stable CuPc and commercial carbon makes the as-prepared PSCs highly durable over 30 days when exposed to the ambient air with a relative humidity of 50%. Since all the processes are conducted under 100 °C, our work paves a way for developing cost-effective and highly stable PSCs compatible with flexible substrates.