Preparation of W/Zr co-doped VO2 with improved microstructural and thermochromic properties

•Successful preparation of Zr/W co-doped VO2 films.•Higher W concentration leads to a significant reduction in Tc.•Ideal Tlum and ΔTsol are obtained in V0.96Zr0.04O2 and V0.95W0.01Zr0.04O2 films. W/Zr co-doped VO2 nanoparticles were successfully synthesized via hydrothermal method with the aim of improving thermochromic properties. The phase transition temperature (Tc) is significantly reduced by an appropriate amount of W doping. The values of luminous transmittance (Tlum) and solar modulation ability (ΔTsol) of VO2 films were significantly improved by Zr doping. The addition of W and Zr has a remarkable influence on the microstructural properties of VO2 nanoparticles, and a dandelion and petals like morphology can be observed for V0.95W0.01Zr0.04O2 and V0.94W0.02Zr0.04O2 samples, respectively. The dandelion-like structure in V0.95W0.01Zr0.04O2 is attributed to the contacting and fusing of the villous structure, and the petals-like structure in V0.94W0.02Zr0.04O2 sample is ascribed to the shrinkage and crimping of the layered structure. V0.95W0.01Zr0.04O2 film has shown an excellent thermochromic properties with Tc, Tlum, and ΔTsol of 46.9 °C, 60.7%, and 10.6%, respectively. Further increase in W concentration has led to degradation in Tlum and ΔTsol values and Tc reduces to near room temperature. This work provides a feasible approach to design W and Zr doped VO2 films for primary application in smart windows.