The CH3NH3PbI3-xClx has been emerged as one of the most promising materials for the photodetector based applications. In recent years, many device structures consisting of hole transporting material, electron transporting material, conducting polymers and noble metals as contact electrodes have been investigated which escort to the increased cost and complexity in the fabrication process. Hence, it is essential to explore low cost, simple processed and high-performance photodetectors. The effect of applied external bias on photodetector has been examined in order to investigate performance. It is important to mention that because of the ion migration phenomenon taking place across the junction at higher bias, an unsaturated photocurrent has been observed during ON time of the photoresponse which may be scope of study for furtherance in low cost and highly stable photodetector. Responsivity and detectivity has been increased by 40 and 32 times at 1.2 V. Similarly, LDR is increased by 8 times.