Enhanced performance of perovskite solar cells using DNA-doped mesoporous-TiO2 as electron transporting layer

[Display omitted] •Deoxyribonucleic acid (DNA) is doped into meso-TiO2 electron transport layer in perovskite solar cells, and the meso-DNA:TiO2 is fabricated without anneal, which can simply the production process of devices.•Optimized band alignment, decreased trap state density and increased electron extraction after DNA doping are beneficial for improving the performance of the PSCs. Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted tremendous attention because of their rapid improvement in power conversion efficiency (PCE) over past couple of years. However, electron transporting material, as the necessary part of an integral PSC, is suffering from higher trap state density and mismatched band alignment level with perovskite absorber layer. The strategy of ion doping in electron transporting layer (ETL) is normally applied to enhance the qualities mentioned above. Herein, deoxyribonucleic acid (DNA) with various concentrations is used as dopant into mesoporous-TiO2 (meso-TiO2), which is manufactured by hydrothermal method. It is found that DNA-doping tremendously decreases the trap state density in meso-TiO2, and these traps are major non-radiative recombination centers for carrier in devices, therefore, the carrier recombination rate for PSCs is also decreased along with the reduction of the trap state. Moreover, when 0.2 mg/mL DNA is used as dopant into meso-TiO2, the meso-DNA:TiO2 exhibits optimized band alignment level with perovskite absorber layer, PCE of the cell based on 0.2 mg/mL DNA doped meso-TiO2 is remarkably boosted to 17.59% from 13.25%. These results demonstrate that meso-DNA:TiO2 as electron transporting material can not only improve the performance of PSCs but also exploit the enormous potential of DNA in the field of photovoltaic devices.