Mechanical energy harvesting is a green technology with great potential for applications in self-powered portable electronics, wireless sensing, implanted devices, and security systems. We have previously reported a triboelectric nano generator (TENG) fabricated from poly(vinylidene fluoride) (PVDF) electrospun nanofibers. This device enabled harvesting of mechanical energy and exhibited an output voltage of 210 V. Here we report doping of the PVDF nanofibers with silica (SiO2) nanoparticles, which increased the output performance of the resultant TENG devices. The output peak to peak voltage was increased to 370 V as the SiO2 nanoparticles content was increased to 0.6 wt % and then declined with further increases in SiO2 content. Hydrophobic SiO2 nanoparticles (mSiO(2)) were prepared by an octanol treatment and markedly increased the performances of the resulting TENG devices. An output peak to peak voltage of up to 430 V was achieved with 0.8 wt % mSiO(2) representing a 48% increase over the value obtained from a PVDF-0.8 wt % SiO2 nanofiber-based TENG. On the basis of our high performance TENG devices, we developed a self-powered digital thermometer for temperature measurement without a battery.