Research Projects

In recent times, the discovery of metal-halide perovskites (MHP)having outstanding photophysical and optoelectronic properties has revolutionized the fields of photovoltaics as efficient photo absorbers in next-generation solar cells. Beyond the conventional three-dimensional MHPs (AMX3; A=Cs+, CH3NH3+; B=Pb2+, sn2+; X=Cl−, Br−, I−), the layered MHPs with lower dimensions (two-dimensional perovskites) have emerged as a more favourable alternative as a result of greater moisture stability and tunable photophysical properties by the inclusion of hydrophobic organic spacer moieties between the inorganic layers. Moreover, the presence of Pb2+ as environmentally hazardous metal centres in state of art perovskites is not recommended for their commercialization. As a result, the direction of perovskite research has been shifted towards more environment-friendly and stable lead-free layered MHPs. Despite the tremendous progress of perovskite halide materials and their structural properties related to their applications in the last decade, limited attention has been paid towards thermal transport properties which are essential for their applications in current technologies. Recent thermoelectric studies of 3D MHP ensure their remarkable seebeck coefficients and ultra-low thermal conductivities. However, the unique two-dimensional structures and anisotropy of the bonding environment of the 2D layered MHPs ensure their much low thermal conductivity and hence better thermoelectric materials. Although such beneficial properties of the 2D layered perovskites towards thermoelectrics, they have not been applied as thermoelectric materials expect very few reports.11 In this proposal, I plan to synthesize different types of lead-free hybrid layered double perovskites (HLDP) with the general formula ofR'4M(I)M(III)X8[Ruddlesden Popper (RP)] or R''2M(I)M(III)BX8 [R' and R'' are monoammonium and diammonium spacer cations; M(I) and M(III) are monovalentand trivalent metal cations; X is the halide anions] by the choice of either R' and R'' or metal centres [M(I) and M(III)] at the inorganic layer in the form of single crystals. The obtained HLDP materials will be applied for the measurements of transport properties i.e thermal conductivity, Hall measurement, heat capacity, electrical transport as well as dielectric measurements.