Research Projects

In recent years, lead halide perovskite has achieved significant attention from the scientific community due to its exceptional performance in the field of optoelectronic device application. Excellent optical, electronic and charge transport properties have contributed to the highly efficient device performance of this class of materials. But it is also observed that exciton recombination is one of the limiting factors reducing the efficacy of the solar cell and other optoelectronic devices. Inspired from the understanding of doping mechanism and charge transport of organic solar cell, in recent years there were a few reports which are also aimed at improving the efficiency by molecular doping of the perovskite layer. It is expected that the molecular dopant can lead to the formation of charge transfer state resulting in the efficient dissociation of exciton, reduction in exciton recombination and trapping of charge carriers. Moreover, the built-in electric field due to the charge transfer can also assist in the formation of free charge carrier after photoexcitation. Thus, the effect of doping on the device performance and stability is of prime interest for the further progress of the suitable design of perovskite-dopant systems. In this respect, charge transfer with the dopant can lead to the p-n junction formation due to the suitable positioning of the host and dopant energy levels. The charge transfer from dopants to perovskite or vice-versa can shift the Fermi levels of the perovskite layer. In this project, halide perovskites will be doped with high mobility p-and n-type diketopyrrolopyrrole (DPP) based organic semiconductors to study the effect of the formation of charge transfer state on optoelectronic applications like photovoltaics and photodetectors. The doping of perovskite with DPP can control the nature of major charge carriers as well as tune the defect density which has great implications for the efficiency of photovoltaic devices. Thus, in summary, the project will investigate the effect of DPP-based p-and n-type molecular dopants on the electronic, optical and charge transport behaviour of perovskites and compare the device efficacy with the undoped devices.