Hole-Conductor-Free, Metal-Electrode-Free TiO₂/CH₃NH₃PbI₃ Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode

Abstract

Low cost, high efficiency, and stability are straightforward research challenges in the development of organic-inorganic perovskite solar cells. Organolead halide is unstable at high temperatures or in some solvents. The direct preparation of a carbon layer on top becomes difficult. In this study, we successfully prepared full solution-processed low-cost TiO2/CH3NH3PbI3 heterojunction (HJ) solar cells based on a low-temperature carbon electrode. Power conversion efficiency of mesoporous (M-)TiO2/CH3NH3PbI3/C HJ solar cells based on a low-temperature-processed carbon electrode achieved 9%. The devices of M-TiO2/CH3NH3PbI3/C HJ solar cells without encapsulation exhibited advantageous stability (over 2000 h) in air in the dark. The ability to process low-cost carbon electrodes at low temperature on top of the CH3NH3PbI3 layer without destroying its structure reduces the cost and simplifies the fabrication process of perovskite HJ solar cells. This ability also provides higher flexibility to choose and optimize the device, as well as investigate the underlying active layers.

Free-standing flexible carbon electrode for highly efficient hole-conductor-free perovskite solar cells

“…Recently, several research groups reported PSCs with carbon materials [25][26][27][28][29][30][31][32][33][34]. Han et al post-deposited perovskite materials into the mesoporous TiO 2 /ZrO 2 /carbon monolithic structure of the HTM-free PSC, and achieved a high PCE of 12.8%, however, the carbon layer needs to be sintered at 400°C, which limited their fabrication on a plastic substrate [26].…”

Highly Efficient 3rd Generation Multi-Junction Solar Cells Using Silicon Heterojunction and Perovskite Tandem: Prospective Life Cycle Environmental Impacts

“…The production of the PSC layer causes only between 5 and 12% of the greenhouse gas emissions of the mono-Si wafer (and between 11 and 18% of the poly-Si wafer). The 30-year lifetime with degradation of 0.7% per year used for the underlying calculations of the results shown in Figure 5 is very optimistic for single-junction PSC compared to the current lifetime [6][7][8][9][10][11][12][13]. However, per kWh of electricity produced, a relevant share of the life cycle greenhouse gas emissions is caused by the production of the module and the balance-of-system components like the inverter and the mounting system.…”

Progress of interface engineering in perovskite solar cells

“…Typically, there are two main methods of implanting carbon electrodes. One is the direct printing on the as-prepared substrates with perovskite layers, which needs a low-temperature processed carbon electrodes paste [69,70]. The other is the construction of carbon electrodes based mesoscopic substrates followed by the infiltration of the perovskite materials, and the carbon layers are normally prepared with high temperature annealing [71,72].…”