Enhanced Flexibility and Stability in Perovskite Photodiode-Solar Cell Nanosystem Using MoS₂ Electron-Transport Layer

Hybrid organic-inorganic perovskites and MoS₂ are highly attractive as emerging materials for various kinds of optoelectronic devices. Here, we first report perovskite photodiode-solar cell nanosystems (PPSNs) by employing bilayer (BL) MoS₂ and triethylenetetramine-doped graphene (TETA-GR) as the electron-transport layer (ETL) and transparent conductive electrode (TCE), respectively. The rigid/flexible PPSNs exhibit 0.42/0.40 AW^-1 responsivity (R), 37.2/80.1 pW Hz^-1/2 noise equivalent power, 1.1 × 10¹⁰/5.0 × 10⁹ cm Hz^1/2 W^-1 specific detectivity at a zero-bias photodiode mode (i.e., self-power operation), similar to or even greater than those of previous reports, and 14.27/12.12% power conversion efficiency at a photovoltaic mode. The PPSNs show high long-term stabilities by maintaining more than 78% of the initial R for 30 days. The flexible PPSNs maintain about 80% of the original R during 1000 bending tests at 4 mm radius of curvature, indicating excellent mechanical properties. These high performances result from the enhanced TCE properties, well-matched band offsets at the cathode/ETL/active layer interfaces, and the reduced carrier recombination/charge-transfer resistance by the use of TETA-GR TCE and BL-MoS₂ ETL.