Ductile-Metal Ag as Buffer Layer for Flexible Self-Powered Ag2S Photodetectors

The rigid nature of inorganic semiconductors makes them rarely use in flexible devices till now. For the first time, ductile-metal Ag is used as buffering layer to bond the inorganic semiconductor thin films and polymer substrate forming a sandwich structure, which has outstanding flexible photoelectric character. The ductile thin Ag layer under Ag 2 S thin film acts as electrode and buffering material between the Ag 2 S and polyimide (PI) layers. The strong bonding interaction between Ag 2 S and Ag can reduce the stress force in Ag 2 S thin films that is generated during bending, which enhances its flexibility. The resulted Ag 2 S/Ag/PI film shows excellent electrical performance retentivity. After more than 10 4 cycles bending test, the conductivity of the Ag 2 S/Ag/PI films has almost not changed. The prepared Au/PEDOT:PSS/Ag 2 S/Ag/PI photodetectors are stable in air or N 2 . It can bear a small bending radius as low as 1.5 mm for ≈4000 bending cycles test without drastic performance decay. In addition, the Ag 2 S/Ag based flexible photodetectors show a wide spectral response from ultraviolet to near infrared.