Perovskite compounds have attracted great attention in photovoltaic research recently. The devices are typically fabricated based on condensed or mesoporous TiO2 layer as the electron transport layer, and 2,2'7,7'-tetrakis-(N,N-dip-methoxyphenylamine)9,9'-spirobifluorene (spiro-OMeTAD) as the hole transport layer. However, high-temperature processing (450OC) requirement of the TiO2 layer could hinder the widespread adoption of the technology. In this report, we adopted a low-temperature processing technique to attain high-efficiency devices in both rigid and flexible substrates. The device structure substrate/ITO/PEDOT:PSS/CH3NH3PbI3-xClx/PCBM/Al was adopted, where PEDOT:PSS and PCBM are used as hole and electron transport layers, respectively. Mixed halide perovskite, CH3NH3PbI3-xClx, was used due to its long carrier lifetime and good electrical properties. All of these layers are solution processed under 120 oC. Based on the proposed device structure, in rigid substrates (glass/ITO), power conversion efficiency (PCE) of 11.5% is obtained, and a 9.2% PCE is achieved for polyethylene terephthalate/ITO flexible substrate.