Zn-alloyed MAPbBr₃crystals with improved thermoelectric and photocatalytic properties

The B-site doping of organic-inorganic lead halide perovskites of the form MAPbX3 is not only an effective way to improve energy conversion (solar-electrical, thermal-electrical, solar-chemical, etc.) performance, but it is also eco-friendly, reducing the toxic Pb content. To the best of our knowledge, there are few reports on the photocatalytic and thermoelectric properties after the partial doping of Zn2+ into the Pb2+ lattice sites of perovskite MAPbBr3 crystals fabricated through a solvothermal route (Zn-MAPbBr3). Systematic characterization, including XRD, EDS, XPS, UV-vis, PL, N2 adsorption/desorption, Hall measurement, time-resolved photoluminescence measurement (TRPL), and electrochemical analysis, showed that the smaller Zn2+ guests increase the Goldschmidt tolerance and octahedral tilting factor of MAPbBr3 and enhance the carrier concentration, carrier mobility and conductivity, active site number, and oxidation abilities of Zn-MAPbBr3. Finally, Zn-MAPbBr3 crystals exhibited an improved absorption capacity and better photocatalytic degradation performance toward RhB dye and improved thermoelectric transportation properties, including better electrical conductivity and a more positive Seebeck coefficient, compared with pristine MAPbBr3.