Zhihui Feng

Effect of ZnCdTe-Alloyed Nanocrystals on Polymer–Fullerene Bulk Heterojunction Solar Cells

The photovoltaic properties of solar cell based on the blends of poly[2-methoxy-5-(2-ethylhexoxy-1,4-phenylenevinylene) (MEH-PPV), fullerene (C60), and ZnCdTe-alloyed nanocrystals were investigated. Comparing the spectral response of photocurrent of the MEH-PPV:C60(+ZnCdTe) nanocomposite device with that of the devices based on MEH-PPV:C60and pristine MEH-PPV, one can find that the nanocomposite device exhibits an enhanced photocurrent. In comparing the composite devices with different ZnCdTe:[MEH-PPV + C60] weight ratios of 10 wt% (D1–1), 20 wt% (D1–2), 40 wt% (D1–3), and 70 wt% (D1–4), it was found that the device D1–3exhibits the best performance. The power conversion efficiency (η) is improved doubly compared with that of the MEH-PPV:C60device.

Annealing effect on the carrier transport in (2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene): C60 bulk heterojunction

Using time-of-flight technique, the annealing effect on the carrier transport in (2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) and MEH-PPV:C60 bulk heterojunction (BHJ) is investigated. Hole mobility drops evidently for the annealed samples compared to the as prepared sample. By analyzing the temperature dependence of field dependent mobility in the Gaussian disorder model, the drop of hole mobility can be attributed to the large value of both positional disorder and energetic disorder, which are 4.47 and 0.132 eV, respectively. However, hole mobility is enhanced for the samples annealed after preparing Al electrodes. Although electron mobility is measurable for the as prepared MEH-PPV:C60 devices, it is below the measurable range as long as the devices experience thermal treatment. The morphology of the annealed samples is investigated by scanning electron microscope and atomic force microscopy. The results manifest that the enhancement of the efficiency for the annealed MEH-PPV:C60 BH...