Charge-Selective Contact Materials for Perovskite Solar Cells (PSCs)

This chapter attempts to give a systematic introduction about the choices of both electron- and hole-selective contact materials for efficient perovskite solar cells (PSCs). A huge number of hole-selective electron-blocking materials (HTMs) have been synthesized for PSCs, which can be generally divided into organic and inorganic HTMs. In typical PSCs, the electron-selective contact material (ETM) is responsible for selective extraction of electrons at the anode contact, adopted from dye-sensitized solar cells (DSSCs) and blocking holes from recombination with injected electrons. Similar to its counterpart HTM, the ETM can be divided into inorganic ETM, organic ETM, and composite ETM depending on the nature of the material. It is desirable that selective contact materials have larger bandgaps than that of perovskite films to avoid the excitons from recombining at the electrode. Also, it is crucial to design and synthesize selective contact materials with high conductivity to reduce the series resistance of the PSCs.