Tuning photoconductive properties of organic–inorganic hybrid perovskite nanocomposite device via organic layer's thickness

Abstract

Two-dimensional (2D) layered organic–inorganic hybrid perovskite (CnH2n+1–NH3)2(CH3NH3)m−1PbmI3m+1 (abbreviated as CnPbmI3m+1; n=4, 8, 12; m=1, 2, 3), with its unique self-assembly and photoelectric properties, has been proposed to functionalize for applications in photoconductive integrated devices. Special devices with the heterostructure of ITO/TiO2/TiO2:CnPbmI3m+1/Pt were fabricated through a facile physical-chemical process. The relationship of the photoconductive performance of the devices and device structures was systematically investigated. The photoconductivity can be optimized by adjusting the alkyl chain length (n) or inorganic sheet thickness (m) of the hybrid perovskite. The photocurrent of the device shows a negative and positive dependence with n and m, respectively. Particularly, a high ratio value of 3.96×104 of the photocurrent and dark current (Ji/Jd) is achieved for the ITO/TiO2/TiO2:(C4H9NH3)2Pb3I10/Pt device at the bias voltage of 1.0V. That is due to the fact that both the shortened alkyl chain and thickened inorganic sheet can facilitate the exciton dissociation at the donor–acceptor interface and enhanced the carrier transport.