Photocurrent density-voltage curves and variation of conversion efficiency. Photocurrent density-voltage curves of 3-D selenium ETA solar cells (a) and the variation of conversion efficiency (b) with different TiO2 particle sizes used for the porous TiO2 layer. The annotation numbers in Figure 6a suggest the sizes of the nanocrystalline TiO2 particle utilized for the electrodes.
Nguyen et al. Nanoscale Research Letters 2013 8:8 doi:10.1186/1556-276X-8-8