Effect of Bromine Doping on Charge Transfer, Ion Migration and Stability of the Single Crystalline MAPb(BrxI1−x)3 Photodetector

National Science Centre

Organic-inorganic halide perovskites (OIHPs) have emerged as a promising semiconductor for the fabrication of efficient optoelectronic devices such as photodetectors (PDs). Among all perovskite composition, the mixed-halide MAPb(BrxI1−x)3 formulations have gained more attention for the photodetection application thanks to their tunable optoelectronic properties and great stability. However, there is still a lack of sufficient understanding of the Br doping on the stability and physical properties of MAPb(BrxI1−x)3 based PDs. In this work, we prepare a series of MAPb(BrxI1−x)3 (x = 0, 0.04, 0.08, 0.12, 0.16) single crystals (SCs) and investigate the influence of the Br content on the crystal structure, charge transport, ion migration, and recombination phenomena. Moreover, self-powered PDs with a structure of Pt/MAPb(BrxI1−x)3 SCs/Pt have been developed, and their optoelectrical properties under different wavelengths of light sources (blue, green, red, and white) have been studied. We found that all the PDs exhibit the highest photoresponse under white light indicating their potential for broad spectrum detecting applications. Particularly, the MAPb(Br0.16I0.84)3 SC PD exhibits highest responsivity of 2.41 mA/W under white light intensity, while the highest detectivity of 15.41 × 1010 Jones was observed for MAPb(Br0.12I0.88)3 SC PD due to the less amount of trap states and suppressed ion migration, as proved by impedance spectroscopy. Finally, photostability and one-year shelf-life stability of the corresponding PDs are demonstrated.